Processes doi: 10.3390/pr14111796

Authors: Yu Kang Yang Guo Jinchao Zhu

To clarify the effect of water immersion duration on the spontaneous combustion behavior of high−sulfur coal, coal samples with a sulfur content greater than 3% were immersed for 15, 30, and 45 d. Mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), Fourier−transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) were used to characterize the pore−fracture structure, surface micromorphology, functional−group distribution, and thermal response of the samples. The results show that, with increasing immersion duration, the pore−fracture system gradually evolved from local opening to enhanced connectivity, while the coal surface became rougher and more porous. The 45 d sample exhibited the most pronounced pore−fracture openness. FTIR analysis indicated staged changes in oxygen−containing functional groups after immersion, with the strongest hydroxyl (−OH) response occurring in the 45 d sample. TGA results showed that the main reaction stage of the immersed samples shifted toward a higher temperature region; the 30 d sample showed relatively prominent mass−loss and heat−release intensities, whereas the 45 d sample exhibited more evident pore−fracture openness, functional−group activation, and a stronger tendency for heat accumulation. Overall, prolonged water immersion strengthened coal–oxygen contact conditions and self−heating sensitivity in high−sulfur coal, and the 45 d sample showed the highest potential spontaneous combustion propensity.

Processes doi: 10.3390/pr14111798

Authors: Kun Li Xue Lian Hanqiao Che Jiansheng Bai Bin Liu

Particle-laden pipe flows are ubiquitous in food, chemical and pharmaceutical processes, where solid particles significantly alter fluid deformation and mixing. Understanding these transport mechanisms is critical for process optimisation. A Lagrangian analysis framework based on a SPH-DEM simulation is proposed to compute finite-time Lyapunov exponent (FTLE) fields and extract Lagrangian coherent structures (LCSs) for non-Newtonian particle-laden pipe flows. The method directly exploits the inherently Lagrangian particle trajectories and computes the FTLE fields using the SPH interpolation scheme, avoiding the costly numerical integration required by conventional Eulerian approaches. Subsequently, LCSs are extracted via a ridge detection algorithm and the combined FTLE is introduced to quantify mixing intensity. The framework is validated against the Kármán vortex street benchmark, showing good agreement with experiment and numerical results. Then the validated framework is applied to non-Newtonian particle-laden pipe flows for a wide range (0 vol.%~30 vol.%) of particle loading. Results reveal a critical concentration range of 20 vol.%~30 vol.%, where the cross-sectionally average combined FTLE increases with concentration up to 20 vol.%, indicating enhanced mixing, but decreases beyond 30 vol.% as particle–particle interactions suppress near-wall fluid deformation. These findings provide a robust Lagrangian tool and new quantitative insights for optimising mixing and transport in industrial particulate flows, such as in food processing pipelines and chemical reactors.

Processes doi: 10.3390/pr14111797

Authors: Yuan Tian Yinghua Zhang Jia Liu Yukun Gao Shengjie Teng

Efficient capture of respirable dust remains difficult in fully mechanized excavation roadways because fine particles readily migrate with airflow beyond the effective spray region. Here, a wind-assisted negative-pressure dust suppression device was developed by integrating annular Venturi entrainment with a mechanical air duct, enabling coupled airflow induction and droplet transport. The device was optimized using nozzle atomization tests, CFD-based orthogonal simulations, and laboratory-scale validation. The results show that an SK508 solid-cone nozzle provides suitable atomization for Venturi-induced suction. Using induced air inlet velocity and diffuser-inlet static pressure as evaluation indicators, the optimal Venturi unit was obtained at 0.1 MPa water pressure, 0.4 MPa air pressure, a 15° diffuser angle, and a throat-center nozzle position. For the integrated device, the best configuration was ten Venturi tubes, an impeller rotational speed of 2400 r/min, and an impeller position of 300 mm from the air duct inlet. In laboratory-scale tests, the complete wind-assisted negative-pressure mode outperformed fan-only, spray-only, wind-assisted spray, and negative-pressure secondary dust suppression modes, achieving maximum total and respirable dust suppression efficiencies of 87.39% and 86.68%. The results demonstrate the feasibility of coupling mechanical airflow with Venturi entrainment and support subsequent field-scale validation.

Processes doi: 10.3390/pr14111795

Authors: Mia-Andree El Jaouiche Eliane Dahdah Yorgo Farah Mantoura Nakad Bilal El Khoury Dayan Chlala Jean Claude Assaf Jane Estephane

This study focuses on the design, optimization, and evaluation of a biodiesel production process involving the transesterification of waste cooking oil (WCO) using a heterogeneous calcium oxide (CaO) catalyst derived from waste eggshells. The work is divided into two main parts. The first focuses on the laboratory preparation, characterization, and performance of the CaO catalyst, while the second translates the experimentally optimized conditions into a process-scale model using Aspen HYSYS to assess industrial feasibility. Waste eggshells were cleaned, dried, ground, and calcined at high temperature to produce the CaO heterogenous catalyst. The catalyst was characterized by Simultaneous Thermogravimetric-Differential Scanning Calorimetry (TG-DSC) and Fourier Transform Infrared Spectroscopy (FTIR). Transesterification experiments were conducted in a batch round-bottom flask reactor where CaO was added to sunflower oil and methanol, and multiple operating parameters were varied to determine the optimal conditions. The catalyst exhibited its best performance after calcination at 900 °C for 2 h. A maximum biodiesel yield of 95 wt.% was obtained at a methanol-to-oil molar ratio (MOMR) of 9:1, reaction time of 2 h, stirring speed of 700 rpm, temperature of 60 °C, and catalyst amount of 3 wt.%. In addition, the eggshell-derived CaO catalyst maintained a biodiesel yield close to 95% over three consecutive reuse cycles, demonstrating good reusability and catalytic stability. The produced biodiesel complied with ASTM standards. Based on these results, the process was then scaled up by simulating a continuous industrial biodiesel production plant using Aspen HYSYS. The model proved practical, achieving a biodiesel purity of 99.85%. Further process optimization, including methanol recovery and heat integration, reduced fresh methanol consumption by 60% and overall energy requirement by 25%. The combined experimental and simulation results demonstrate that energy efficiency and waste valorization enable a biodiesel production pathway that is both environmentally and economically sustainable and aligned with circular economy principles and sustainable development goals.

Processes doi: 10.3390/pr14111794

Authors: Kang Li Daizong Shi Weibin Wang Chaofei Nie Dongxu Han

Traditional inter-station crude oil heating processes rely heavily on fossil fuels, leading to high energy consumption and environmental pollution. To address this issue, this paper develops a dynamic thermal simulation model for a novel pipeline heating system that couples geothermal and solar energy. The model synergistically utilizes abundant solar energy and abandoned geothermal well resources in the Jilin region, and is applied to analyze the thermal performance of the Xinmiao Station on the Qingtie Fourth Line pipeline. The results show that the system achieves approximate thermal stabilization during long-term operation: the produced water temperature stabilizes at approximately 30.85 °C, and the average coefficient of performance (COP) of the heat pump remains above 4.79, demonstrating good stability. Solar energy contributes about 23.5% of the total annual heat supply (7.0 × 106 kWh) over 1600 effective hours, significantly reducing the annual electricity consumption of the heat pump and water pumps. The integration of solar energy effectively mitigates the decline in the average soil temperature; after 25 years, the soil temperature remains at approximately 54.43 °C. Through optimized configuration, the system reduces its life-cycle cost and levelized cost of heat (annual cost reduced by about 4.35%), showing excellent economic performance. Comprehensive analysis indicates that the coupled system exhibits outstanding energy efficiency and sustainability, providing technical support for the optimized design and engineering application of clean heating systems for crude oil pipelines. This paper contributes four novelties: first application of a coupled geothermal–solar system to a crude oil pipeline (Xinmiao Station, Qingtie Fourth Line); reuse of abandoned deep oil wells as geothermal boreholes to cut drilling costs; a 25-year dynamic simulation quantifying long-term soil temperature evolution and proving sustainability gains over a standalone geothermal system; and multi-scenario economic optimization identifying the optimal collector area under site land constraints. Based on these, a dynamic thermal simulation model is developed and its synergistic operation strategy is investigated, aiming to provide theoretical and technical support for clean-energy-driven crude oil heating.

Processes doi: 10.3390/pr14111793

Authors: Junjie He Qian Li Xuyong Liu Hehong Deng Tongyi Li Siwei Wei

(Objective) To improve the accuracy and efficiency of lithology identification and formation parameter prediction during drilling, the study used drilling parameter data and implemented SVM, XGBoost, random forest, LightGBM and an ensemble of five algorithms for comparative experiments under baseline, noise interference (10% and 20% noise levels) and data imbalance scenarios. (Results) In lithology identification, the stacking ensemble achieved accuracies of 86.80% and 83.10% under 10% and 20% noise scenarios respectively. The accuracy of the random forest algorithm was 91.15% for the baseline scenario, and for the imbalanced scenarios (10% and 5%), the accuracies were 88.9% and 88.1%, respectively. In formation parameter prediction, random forest achieved mean absolute errors (MAEs) of 3.45, 0.0019, 0.0008 and 0.0004 for seismic velocity, pore pressure, fracture pressure and overburden pressure in the baseline scenario and performed best under noise and imbalanced data conditions. (Conclusions) An adaptive hybrid model was ultimately established: stacking ensemble is used for lithology prediction in noisy environments, while random forest is used for lithology prediction in non-noisy environments and for formation parameter prediction across all environments.

Processes doi: 10.3390/pr14111792

Authors: Xinxin Chen Yanjun Ma Duanjiao Li Wenxing Sun Junjun Zhang Dejun Ba Lijun Hang Xiaofeng Lyu

This paper addresses the capacitor voltage balancing issue of submodules (SMs) in Modular Multilevel Converters (MMCs) operating under low switching frequencies by proposing a voltage balancing control strategy based on dynamic threshold adjustment. First, a dynamic model of SM capacitor voltage in MMCs is established, and the causes of capacitor voltage imbalance are analyzed. Then, based on the coupling relationship between switching frequency and voltage balancing, and the imbalance model under dynamic operating conditions, a dynamic threshold adjustment strategy is designed. A Fuzzy Logic Controller (FLC) is employed to dynamically adjust the voltage imbalance threshold in real time, ensuring capacitor voltage balance while optimizing the switching frequency and reducing system losses. Simulation results show that the proposed strategy can effectively maintain SM capacitor voltage balance under low-switching-frequency conditions, thereby improving system stability.

Processes doi: 10.3390/pr14111789

Authors: Fabiano A. N. Fernandes Sueli Rodrigues

The global food system faces high pressure to sustain a growing population amid climate constraints and shifting consumer demands, making the traditional trial-and-error development methodologies inadequate. Artificial Intelligence (AI) has transitioned from a simple optimization tool into a structural enabler across the entire food chain. This review examines the integration and evolution of computational architectures in food technology between 2006 and 2026, tracing the paradigm shift from the early fuzzy logic and rule-based systems to modern deep learning and generative frameworks. This review highlights breakthroughs achieved over the last five years, demonstrating how Graph Neural Networks, Transformers, and Variational Autoencoders and other architectures are accelerating the in silico discovery of bioactive ingredients, predicting complex molecular flavors, and autonomously synthesizing optimal culinary formulations. The transition to Industry 5.0 is also explored, emphasizing the integration of collaborative robotics, process-level digital twins, and federated learning to enable autonomous manufacturing and privacy-preserving precision nutrition. Finally, this review addresses critical barriers to commercialization, including severe data fragmentation, the “Innovation Paradox” in fundamental academic research, and the urgent need for multidisciplinary teams capable of translating digital predictions into physically stable, strictly regulated food matrices.

Processes doi: 10.3390/pr14111790

Authors: Fernanda Ribeiro Figueiredo Roymel Rodríguez Carpio Diego Martinez Prata Argimiro Resende Secchi

Purification of isobutane remains a fundamental step in the production of a cleaner alkylated gasoline, and the distillation operation employed for this separation is notoriously energy-intensive and a significant contributor to environmental impacts. To address these challenges, this work proposes vapor recompression (VR) as an intensified alternative process to fully electrify the conventional column–reactor configuration used in n-butane isomerization and separation. An external VR scheme was designed and globally optimized with the objective of minimizing total annualized cost. The optimized VR configuration showed a clear economic advantage, achieving an approximate 13.83% reduction in costs over a 10-year horizon with a break-even time of 7.13 years. Additionally, overall energy demand was reduced by 74%, and operational safety was enhanced, as the boiler is required only during plant start-up and shutdown. To account for economic uncertainty, a sensitivity analysis was conducted to evaluate the effects of fluctuations in electricity and steam prices. Environmental performance was further assessed through CO2 emissions using different national electricity emission factors. While emission reductions depend strongly on grid carbon intensity, regions with low-carbon electricity mixes show significant mitigation potential. Overall, VR emerges as a promising strategy to improve the economic and environmental sustainability of industrial processes.

Processes doi: 10.3390/pr14111791

Authors: Icaro B. Boa Morte Israel Bernardo S. Poblete Cláudia R. V. Morgado José Luiz de Medeiros Ofélia de Queiroz Fernandes Araújo

Carbon taxes and credits (CT&C) accelerate global deployment of carbon capture, utilization and storage (CCUS) technologies to enable energy transition. This study investigates the economic performance and resilience of floating gas-to-wire with CCUS (f-GTW-CCUS), deployed at the wellhead of stranded CO2-rich offshore oil and gas reservoirs. The f-GTW-CCUS platform integrates a natural gas combined cycle power plant with monoethanolamine post-combustion capture (PCC-MEA), producing low-carbon electricity (23 kgCO2e/MWh, competitive with renewables) while monetizing captured CO2 via enhanced oil recovery (EOR). The mass and energy balance data from the proposed process configuration were obtained in the literature. Critically, f-GTW-CCUS operates on wellhead-sourced in situ-associated gas, eliminating exposure to volatile natural gas markets, and achieves a levelized cost of electricity (LCOE) of USD 67.15/MWh. Monte Carlo analysis (10,000 Gaussian iterations, 30-year lifetime, 10% discount rate, three CT&C scenarios, namely, low/medium/high) is used to quantify economic feasibility across three stochastic variables: oil, natural gas, and electricity prices, starting in the 5th year. The results demonstrate the following: (1) Case A (f-GTW without CCUS) remains economically infeasible (NPV < 0) under all price volatility scenarios due to insufficient electricity-only revenue and carbon taxation penalties; (2) Case B (f-GTW-CCUS with immediate CCUS deployment) maintains positive NPV across all scenarios, with EOR monetization contributing 43% of total revenue; (3) the critical CCUS deployment-delay threshold is 6 years under high carbon taxation, extending to 10 years when carbon credits are included. Gate-to-gate environmental assessment (carbon intensity, water footprint, land transformation) shows f-GTW-CCUS superiority versus alternative power systems, with minimal water–land nexuses due to offshore desalination. An empirical consistency assessment based on the 2026 geopolitical energy crisis demonstrates the structural resilience of the f-GTW-CCUS plant: the wellhead sourcing provides resilience to global natural gas price shocks, while the concurrent crude price escalation amplifies EOR revenues by 43–57%, improving project feasibility during commodity disruptions. These findings position f-GTW-CCUS as a critical decarbonization pathway for O&G producers exploiting stranded gas reserves. The technology combines carbon intensity reduction with economic resilience under volatile energy market conditions and mandatory climate policies.

Processes doi: 10.3390/pr14111788

Authors: Rojiar Pishkari Achim Kienle

Efficient and accurate simulation methods are essential for analyzing and optimizing chromatographic processes, which are governed by partial differential equations (PDEs) and characterized by the propagation of steep concentration fronts. These fronts often cause numerical dispersion and high computational costs in conventional finite-volume or finite-difference schemes. In this paper, a fast and accurate simulation method for highly efficient chromatographic columns with negligible axial dispersion, linear and nonlinear non-competitive adsorption isotherms is proposed. The simulation approach is based on the propagation of discrete concentration values using characteristic velocities. In the linear case, the method is exact, and only the graphical representation of the solution depends on the discretization of the concentration coordinate. In the nonlinear case, an approximation is proposed to capture the possible formation of discontinuities efficiently. Nevertheless, it is shown that good agreement with reference solutions is achieved even for a relatively low number of discrete concentration values. Applications of the proposed methods are demonstrated for different multi-column simulated moving bed processes. The results show that the computational effort can be significantly reduced compared to the popular cell model, which represents a first-order finite-volume approximation of the underlying PDEs. The proposed approach thus enables rapid process design and parameter exploration for both linear and nonlinear non competitive adsorption isotherms for SMB chromatography separations with highly efficient columns.

Processes doi: 10.3390/pr14111787

Authors: Zhenghua Gao Cheng Meng Fei Wu Tengfei Guo Chun Xu Tiancai Yang

In the process of ascending repetitive extraction of multilayer coal seams, the evolution and expansion of excavation-triggered cracks dominate the structural instability of overlying rock layers and the deterioration of overall rock mass quality. In this study, a similar material model containing two coal seams (No. 2 upper coal seam and No. 4 underlying seam) was constructed. Through model excavation, the entire process of overburden movement was captured, and a box-counting program was developed for quantitative analysis to investigate the dynamic evolution law of overlying strata fractures under upward repeated mining disturbances. The results show that during the mining of the No. 4 coal seam, the fractal dimension of mining-induced fractures initially increases and then decreases, with the peak value occurring at an excavation distance of approximately 40 cm. For the No. 2 coal seam, the fractal dimension exhibits fluctuating evolution characteristics, with the global peak appearing at approximately 55 cm and a local peak at approximately 70 cm. The rate of change in fractal dimension during coal seam mining exhibits alternating fluctuations of increase and decrease. The initially mined No. 4 coal seam, subject to higher in situ stress, exhibits rapid fracture development with an earlier peak, while the No. 2 coal seam, influenced by pressure relief, presents progressive fracturing characteristics with a delayed peak. The fractal dimension can effectively characterize the evolution characteristics of the mining-induced fracture network in overlying strata and provide reference for strata control and disaster prevention.

Processes doi: 10.3390/pr14111786

Authors: Nazym Alzhaxina Anar Kurmanbayeva Mukhtar Tultabayev Inkar Aubakirova Magzhan Mantay Askhat Dalabayev

This study comprehensively assesses the effect of ultrasonic treatment on the physicochemical, nutritional, and rheological properties of mung bean (Vigna radiata) milk. Ultrasonic treatment (24 kHz, 200–300 W, 5–20 min at 25 ± 2 °C) was applied after preliminary aqueous extraction (60–70 °C, 15–20 min) and compared with conventional aqueous extraction (control). Ultrasound significantly increased protein extractability (from 0.11% to 0.15%, p = 0.008) and improved the amino acid profile (8–18% increase without signs of degradation). The content of potassium, phosphorus, and magnesium increased by 6–12% (p < 0.001 for K and P, p = 0.001 for Mg), indicating more efficient release of intracellular components. B-group vitamins remained stable, while fat-soluble vitamins (A, E) were not detected. Total mesophilic microflora was reduced to 1.2 × 104 CFU/mL (p = 0.021), with no pathogenic microflora detected. Rheological measurements confirmed pseudoplastic behavior (n < 1), an increase in viscosity up to 20.0 cP, and the formation of a more homogeneous dispersion. Thus, ultrasonic treatment performed under controlled non-thermal conditions after preliminary aqueous extraction effectively improves the structural, functional, and nutritional quality of mung bean plant-based milk.

Processes doi: 10.3390/pr14111785

Authors: Feng Wang Tong Zhang Yu Tang Yuxuan Liu

Contact sensor-based stress monitoring of transmission towers under strong winds is often limited by complex installation and maintenance procedures and the risk of local structural damage. With the development of non-contact displacement monitoring technologies, such as laser measurement and machine vision, this study proposes a wind-induced stress surrogate model for transmission towers using MISSA-BPNN, aiming to rapidly calculate stresses in vulnerable regions from macroscopic displacement responses. First, finite element analysis is conducted to investigate the wind-induced responses of a tower-line system under different operating conditions, identify vulnerable regions, and construct a dataset using displacement and stress responses. Then, a multi-strategy improved sparrow search algorithm (MISSA) is developed to optimize the initial weights and biases of the BP neural network, thereby establishing the MISSA-BPNN model. The constructed dataset is used to train the model and build the wind-induced stress surrogate model. Results show that the vulnerable regions are mainly located at the leeward tower foot and the middle-lower tower body. Compared with the conventional BPNN model, the proposed MISSA-BPNN surrogate model reduces the MAE, RMSE, and MAPE by 22.43–24.33%. This method provides a new approach for health monitoring of transmission lines under strong winds.

Processes doi: 10.3390/pr14111784

Authors: Na Sun Hongxu He Yunyun Yun Shuaibing Li

The presence of multiple uncertainties in integrated electricity–heat energy systems (E-HIES) poses significant challenges to system dispatch. To achieve an effective balance between economy and robustness, this paper proposes an optimal scheduling method based on fuzzy chance-constrained Information Gap Decision Theory (Fuzzy-IGDT), accounting for uncertainties in wind power output, photovoltaic output, electrical load, and thermal load. The method employs trapezoidal fuzzy numbers to model the four types of uncertain variables and constructs a fuzzy robust model (F-RM) for conservative decision-makers and a fuzzy opportunity model (F-OM) for aggressive decision-makers. An Adaptive Step Ratio (ASR) optimization method is then developed to solve the proposed models. Case studies demonstrate the effectiveness of the proposed methodology. Results show that: compared with conventional IGDT, pure fuzzy and stochastic programming, Fuzzy-IGDT simultaneously optimizes economy, stability and reliability: daily operating cost is reduced by 12.7%, the standard deviation of cost volatility shrinks by 34.5%, and the loss-of-load probability is only 0.3%. Relative to the traditional Weighted Offset Coefficient (WOC) method, ASR directly coordinates the deviation ratios of multiple variables through its step-ratio mechanism, cutting system risk cost by 21.3%, raising solution efficiency by 42%, and improving convergence stability by a factor of 3.8. This research provides new theoretical support and practical tools for optimal scheduling of E-HIES under multiple uncertainties.

Processes doi: 10.3390/pr14111783

Authors: Jian Shi Xiaodong Chen Jinsheng Zhao Jun Yang Xingang Zhang Dong Hao Chen Yang Lin Chen Mingyong Xu

Fracability evaluation is essential for hydraulic fracturing interval selection and stimulation optimization in ultra-low permeability sandstone reservoirs. Conventional brittleness-based methods derived from shale reservoirs are insufficient for characterizing fracture initiation difficulty, fracture propagation resistance, natural fracture interaction, and post-fracture conductivity in tight sandstone formations. In this study, the Chang 6 ultra-low permeability sandstone reservoir in Block H was investigated by integrating triaxial rock mechanical testing, Kaiser acoustic emission stress measurement, FMI/MCI image-log interpretation, and logging-based dynamic-to-static mechanical parameter conversion. The results show that the reservoir is characterized by relatively high stiffness and strength, with an average static Young’s modulus, Poisson’s ratio, and compressive strength of 24.05 GPa, 0.21, and 131.97 MPa, respectively. The all-sample average maximum and minimum horizontal principal stresses are 35.70 MPa and 29.91 MPa, respectively. After excluding the anomalous C6-19 stress-memory response, the representative average σH and σh  are 37.06 MPa and 30.95 MPa, respectively, with a representative stress difference of 6.12 MPa. A multi-factor integrated fracability index was established by considering brittleness, natural fracture development, compressive strength, equivalent fracture propagation resistance, and effective confining pressure. The average fracability indices of Wells L7 and L26 are 0.624 and 0.596, respectively, indicating relatively favorable fracturing potential. The proposed workflow provides a geomechanically constrained method for relative sweet-spot ranking and preliminary hydraulic fracturing design in ultra-low permeability sandstone reservoirs.

Processes doi: 10.3390/pr14111782

Authors: Alejandra Silvina Román Edgar Rolando Ibañez Claudia Marcela Méndez Natalia Silvina Zadorozne Alicia Esther Ares

In the present study, the influence of microstructural morphology and dendritic refinement on the electrochemical corrosion behavior of directionally solidified aluminum-based structures (columnar and equiaxed) with Si contents between 6 and 12.6 wt. % was investigated in a 0.5% NaCl solution at room temperature. Corrosion resistance was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The directional solidification process was repeated for each of the alloy compositions at different cooling rates, yielding different secondary dendritic spacing values. The columnar-to-equiaxed transition (CET) was observed to occur when the temperature gradient in the melt decreased to values between −1.85 and 0.75 °C/cm. In addition, a small increase in the microhardness values was observed as a function of the Si content. The same applies to tensile strength values. The values of the polarization resistance are used as a basic criterion for the evaluation of the corrosion resistance of alloys. The columnar grain zone presents higher corrosion resistance than the equiaxed grain zone, despite presenting coarser dendritic spacing. This behavior contrasts with the commonly expected improvement in corrosion resistance associated with microstructural refinement and indicates that passive-layer stability and cathodic phase distribution play a dominant role in the electrochemical behavior. When the polarization resistance decreases with the increase in the distance from the base, the grain size and secondary dendritic arm spacings increase. In addition, when the polarization resistance increases, the critical temperature gradient decreases. This work allows us to conclude that the modification of thermal parameters in the solidification process can be used for the development of an optimized microstructure morphology and to optimize corrosion resistance in Al–Si alloys through control of dendritic spacing and passive film formation mechanisms.

Processes doi: 10.3390/pr14111780

Authors: Huige Shi Ruiling Fu Zihao Li Guizhou Cao Bingnan Li Zhenlong Wu

Circulating fluidized bed boilers (CFBBs) are widely applied in energy, metallurgy, the chemical industry and other fields, mainly due to their high combustion efficiency and low pollution emissions. However, the CFBB combustion system, as a typical third-order plus time delay (TOPTD) system, has inherent characteristics: large inertia, significant time delays and strong coupling. Coupled with the difficulty in establishing an accurate mathematical model, traditional control methods struggle to achieve the desired control performance. Active disturbance rejection control (ADRC) has prominent advantages, such as low dependence on the controlled plant’s accurate model and strong disturbance rejection ability, but it has obvious limitations in dealing with systems with large inertia and large time delays. To address this problem, this paper proposes an input-compensated active disturbance rejection control (ICADRC) method. An input-compensated part composed of a second-order inertial link and a time delay link is introduced into the ESO input channel, which is specially optimized for the characteristics of TOPTD systems. A set of quantitative parameter tuning rules unique to ICADRC is established via the equivalent approximation method, and a dedicated MATLAB auto-tuning toolbox for ICADRC is developed for TOPTD systems. Simulation experiments are conducted on the CFBB combustion system, and the results show that the proposed ICADRC exhibits superior setpoint tracking performance, disturbance rejection performance and robustness compared with ADRC, DADRC, and SIMC-PI. Under nominal operating conditions, the IAEsum of ICADRC is reduced by 36.2% relative to DADRC and by 54.3% relative to SIMC-PI. Specifically, under fixed parameter perturbations, the variation amplitude of ICADRC’s performance index is only 2.1%, significantly lower than the 5.1% for DADRC, 6.1% for ADRC, and 7.3% for SIMC-PI.

Processes doi: 10.3390/pr14111781

Authors: Wencheng Lin Qingpeng Chen

The tension of a marine winch rope depends on the hydraulic pressure supplied to its input hydraulic motor. Traditionally, winches employ a relief valve to control the oil pressure of hydraulic motors. Owing to the inherent control characteristics of the relief valve, this control mode leads to continuous fluctuations in the system oil pressure, causing severe variations in the rope tension during operation. In this study, a direct-acting three-way proportional pressure-reducing valve was used to control the oil pressure of the winch, ensuring that the input pressure to the hydraulic motor was maintained at a set value, thereby mitigating the risk of drastic fluctuations in rope tension during vessel mooring. However, proportional pressure-reducing valve control exhibits shortcomings, such as static nonlinearities, insufficient dynamic response, and poor anti-interference stability, leading to oscillations in the outlet oil pressure and resulting in rope tension fluctuations in the winch. Based on the force and flow balance equations of the proportional pressure-reducing valve and in conjunction with the load characteristics of the winch, a mathematical model of the winch control system was established. An operating point for the pressure-reducing valve was determined, and the control system model was linearized. According to the Bode plot and frequency-domain index analysis, four key parameters affecting the outlet pressure fluctuation of the pressure-reducing valve were identified (valve port flow gain coefficient, viscous damping coefficient, transient hydraulic damping coefficient, and hydraulic spring stiffness). From the perspective of winch operation management, the working parameters of the hydraulic system were adjusted accordingly, and their effects on the four key parameters were analyzed. The results, in combination with model linearization and Bode plot analysis, indicate that appropriately lowering the operating temperature of the hydraulic oil can effectively improve the frequency-domain indices and stability margin of the control system, significantly enhancing the relative stability of the marine winch rope tension.

Processes doi: 10.3390/pr14111779

Authors: Jin Wang Ming Zhang Wei Huang Chi Zhao Yu Wang

Accurate prediction of pore pressure is crucial for ensuring drilling safety and improving the efficiency of oil and gas development. However, regarding feature selection, most existing studies focus primarily on the correlations among features, with little consideration given to inter-well distribution differences; this may result in insufficient model generalization capabilities for cross-well prediction tasks. To improve cross-well prediction accuracy, this paper introduces the DASP (Domain Adaptation with SHAP-guided Particle Swarm Optimization) method for feature selection. Using 20 logging and rock mechanical parameters as input features, a four-stage selection process reduces the number of features to 12, achieving approximately 40% feature dimensionality reduction. In terms of model performance comparison, models such as RF (Random Forest), XGB (eXtreme Gradient Boosting), LGB (Light Gradient Boosting Machine), and CNN (Convolutional Neural Network) were constructed for comparative analysis. The results indicate that LGB performs better during the validation phase, while in the cross-well testing phase, RF achieves the best prediction accuracy among the base models, demonstrating strong generalization stability. Addressing the issue that CNNs still have room for further optimization in cross-well prediction, this study further refines their architecture by introducing an attention mechanism to enhance the model’s adaptive weighting capability for key features and combining it with a physical constraint mechanism to suppress non-physical prediction fluctuations, thereby improving the model’s stability and geological plausibility. Experimental results demonstrate that the improved model shows significant improvements in both error metrics and fitting capabilities. The combination of the DASP-based feature selection method and the improved CNN model effectively enhances the accuracy of cross-well pore pressure prediction, providing new technical insights and data support for intelligent pore pressure prediction and drilling safety decision-making.

Processes doi: 10.3390/pr14111778

Authors: Xianglong Fang Yidong Cai Longyong Shu Zhonggang Huo Ping Gao Yujing Qian Qixian Li

Organic-rich shales in China’s deep-water shelf environments possess significant shale gas resource potential. To investigate the reservoir development characteristics of deep-water shelf shale, 143 shale samples were collected from the low-maturity Xiamaling Formation in the Zhangjiakou area and the high to over-mature Wufeng–Longmaxi Formations in the southeastern margin of the Sichuan Basin. Basic analytical methods, including X-ray diffraction (XRD), total organic carbon (TOC) analysis, rock pyrolysis, and solid bitumen reflectance measurements, were employed alongside advanced reservoir characterization techniques such as field-emission scanning electron microscopy (FE-SEM), low-pressure CO2/N2 physisorption, mercury intrusion porosimetry (MIP), and focused ion beam scanning electron microscopy (FIB-SEM). This study focuses on the petrographical, geochemical, and microscopic pore structure characteristics of these marine shales. The results indicate that the mineral composition of deep-water shelf sedimentary shale is dominated by quartz, clay minerals, feldspar, calcite, dolomite, apatite, and pyrite, with quartz being the most abundant. The Xiamaling Formation shales, at low maturity, are relatively rich in siliceous components, while the high to over-mature Wufeng and Longmaxi Formation shales are richer in carbonate components. The kerogen type of organic matter in the Xiamaling Formation is primarily Types II1 and II2, whereas the Wufeng–Longmaxi shales are predominantly Types I and II1. TOC content is highest in the Wufeng Formation, followed by the Longmaxi Formation, with the Xiamaling Formation exhibiting the lowest TOC levels. Pore development in the Wufeng and Longmaxi shales is significantly superior to that in the Xiamaling shales. Overall, the Wufeng and Longmaxi Formations demonstrate more favorable pore characteristics and hydrocarbon generation potential compared to the Xiamaling Formation. The Wufeng and Longmaxi Formations’ shales will be the key targets for shale gas exploration in the future. The findings of this study contribute to the understanding and development of theories of marine shale gas accumulation in China and hold both theoretical and practical significance for the efficient and rational exploitation of shale oil and gas resources.

Processes doi: 10.3390/pr14111777

Authors: Yenifer González Pablo Salgado Nikole Guerrero Gladys Vidal

The disinfection process in wastewater treatment is key to the discharge and/or reuse of high-quality effluent. However, disinfection using ultraviolet (UV) light may be inefficient because bacteria possess mechanisms for repairing damaged DNA. This study aimed to assess the photoreactivation and dark repair of total coliform (TC) in wastewater effluent after UV-C disinfection treatment. Four UV-C doses (28.8, 53.1, 57.6, and 106.2 mJ/cm2) and two post-irradiation conditions (light vs. darkness) were applied. Reactivation was monitored after 2, 4, 6 and 24 h (25 °C). Similar TC inactivation efficiencies were observed for the three lowest UV-C doses, whereas the 106.2 mJ/cm2 dose achieved the greatest reduction (1.1 Log of TC), decreasing TC concentrations from 3.1 × 105 ± 3.5 × 105 to 1.2 × 105 ± 1.4 × 105 MPN/100 mL. Reactivation assays revealed substantial bacterial recovery after UV treatment, with 24 h survival rates up to 2.3 × 103 under light and 9.2 × 102 in darkness. Photoreactivation and dark repair assays revealed substantial variability in bacterial recovery after UV treatment depending on UV-C dose, post-irradiation condition and incubation time. In general, bacterial recovery was still detected even at the 106.2 mJ/cm2 dose, particularly after 24 h of incubation (178–604%). These findings suggest that effective organic matter removal before UV-C disinfection is critical to improve UV transmittance, reduce shielding effects, and limit subsequent bacterial recovery.

Processes doi: 10.3390/pr14111776

Authors: Mohd Faheem Khan

Soil biofilms are structured, dynamic microbial consortia embedded within extracellular polymeric substances that regulate microscale physicochemical heterogeneity and drive biogeochemical transformations in soils. Despite increasing interest in biofilm-mediated remediation, current reviews have largely examined microbial ecology, engineered biofilm functions, and predictive modelling independently, limiting systems-level understanding of pollutant fate in complex soils. This review, therefore, proposes a revised conceptual framework integrating biofilm ecology, synthetic biology, and AI-driven predictive modelling to improve mechanistic and predictive understanding of emerging pollutant detoxification. Emerging pollutants, including pharmaceuticals, pesticides, per- and polyfluoroalkyl substances, micro- and nanoplastics, and heavy metals, exhibit persistence, bioaccumulation, and mixture-dependent effects that challenge conventional remediation strategies. Biofilm matrices function as reactive interfaces facilitating adsorption, sequestration, and enzymatic transformation, while steep redox and nutrient gradients support metabolically diverse processes such as cometabolism, syntrophic degradation, and biomineralisation. Increasing evidence indicates that quorum sensing, horizontal gene transfer, and low-abundance microbial taxa contribute significantly to adaptive responses and functional plasticity within biofilms. Advances in high-resolution imaging, spatial multi-omics, and microfluidic platforms have resolved previously inaccessible biofilm architectures and processes; however, integration with machine learning and process-based modelling remains limited, restricting field-scale prediction of pollutant behaviour and remediation outcomes. Synthetic biology enables targeted optimisation of biofilm functions, whereas AI-driven models enhance prediction of contaminant transport, transformation, and detoxification. Soil biofilms function both as sinks and catalytic hotspots, and resolving this duality through a predictive, systems-level framework represents a major advance beyond existing descriptive reviews.

Processes doi: 10.3390/pr14111775

Authors: Juan Hou Jiajun Liu

Hydraulic conductivity tests and numerical simulations were conducted to evaluate the leakage through a geosynthetic clay liner (GCL)–geomembrane composite liner with a geomembrane defect under mechanical–chemical coupled conditions. A circular geomembrane defect with a diameter of 2 to 7 mm was created in the geomembrane to simulate different defect sizes that may be encountered in the field. Hydraulic conductivity tests were conducted on 155-mm-diameter specimens under an average effective stress of 40 or 240 kPa to simulate different layers of waste placed and permeated with the 100 or 250 mM CaCl2 solution to simulate the aggressive waste leachates that could increase the hydraulic conductivity of GCLs. The maximum leakage rate that can be observed in the field was calculated using the equivalent hydraulic conductivity of the composite liner or predicted using finite-element modeling. The results show that the leakage rate of the composite liner with a geomembrane defect was consistently lower than the leakage rate of the GCL alone. The decrease in the size of geomembrane defects, the decrease in leachate concentration, and the increase in effective stress resulted in a decrease in the leakage rate. Nevertheless, the leakage rate of the composite liner was only up to 17× lower than the leakage rate of GCL alone. The composite liner with a geomembrane defect was not able to achieve an equivalent or lower leakage rate than a standard compacted clay liner alone, suggesting that GCLs need to maintain low hydraulic conductivity even with the protection of geomembranes.

Processes doi: 10.3390/pr14111772

Authors: Jingbo Wu Ruoling Dong

Shock-induced gas/water interfacial instability is important in multiphase flow processes involving rapid deformation, mixing, and breakup. In this study, the evolution of shock-impacted gas/water interfaces was investigated using high-speed images from previously conducted shock-tube experiments and two-phase numerical simulations. Interface contours were extracted through digital image processing, and spatial Fourier analysis was used to describe the modal evolution of interfacial perturbations. A numerical model based on the VOSET interface-capturing method and the SST k − ω turbulence model was established, with the compressibility of both phases considered. A mode number–amplitude–time (K-L-t) diagnostic framework was proposed. The results show that this framework can distinguish the dominant stages associated with Richtmyer–Meshkov (RM), Rayleigh–Taylor (RT), and Kelvin–Helmholtz (KH) instabilities. In the double-liquid-column case, the downstream interface exhibits a delayed transition, which may be associated with shielding and wake interference. Increasing the shock Mach number accelerates modal growth and advances the transition times, whereas increasing the liquid-column diameter delays the instability evolution because of larger inertia. A modified RM dispersion equation incorporating compressibility and finite-thickness effects was further proposed, showing improved agreement with the CFD-extracted initial growth rates.

Processes doi: 10.3390/pr14111774

Authors: Jinglei Li Ziran Jiang Xiao Li

Porosity is a key parameter controlling reservoir storage capacity and fluid flow behavior, and its accurate prediction remains a major challenge in complex reservoirs with limited well control. Traditional methods based on well logs and rock physics modeling are often restricted by sparse spatial coverage, while purely data-driven approaches lack physical interpretability and geological consistency. To address these limitations, this study proposes a model–data coupled framework for seismic porosity prediction in sandstone reservoirs. The approach integrates rock physics constraints into a deep learning architecture by embedding relationships derived from the Gassmann equation and critical porosity model into an LSTM-UNet network. This design enables the model to simultaneously capture spatial features and temporal dependencies from seismic data while maintaining physical consistency. Synthetic experiments based on the SEAM model demonstrate that the proposed method achieves stable and accurate porosity predictions under both noise-free and noisy conditions. Application to field data from a real-world study area further demonstrates the effectiveness of the proposed method, with predicted porosity showing strong agreement with well-log data and improved lateral continuity relative to conventional approaches. The results indicate that the proposed framework effectively combines the flexibility of data-driven learning with the interpretability of physics-based modeling, providing a robust and reliable solution for porosity prediction in complex sandstone reservoirs.

Processes doi: 10.3390/pr14111773

Authors: Maha Dassouki Dit Tahan Nada Hosni Meagan Morrow Abir Hamze Meni Mancini Dimitris Chrysochoou Elsayed Elbeshbishy

Anaerobic digestion (AD) of thickened waste-activated sludge (TWAS) is widely applied for sludge stabilization and renewable energy recovery; however, hydrolysis of complex organics often limits fermentation performance. This study evaluated the effects of multiple pretreatment strategies on solubilization, volatile fatty acids (VFAs) production, and extracellular polymeric substances (EPS) during 80 h mesophilic batch fermentation. Pretreatments included hydrothermal treatment (HTP; 70, 90, and 170 °C), ultrasonication (US; 3000, 5000, and 10,000 KJ/kg TS), chemical pretreatment (acidic pH 4 and alkaline pH 10), and biological augmentation using YDRO Process® (YDRO®; 5%, 10%, 15% v/v). Across feedstock pretreatments, HTP generated the greatest improvements in solubilization, increasing SCOD by 56–113-fold and producing substantial acetate levels, particularly at 70 °C, alongside substantial phosphorus release. Ultrasonication resulted in moderate solubilization (28–56-fold) and elevated soluble phosphorus and ammonia. Acidic pretreatment maximized soluble phosphorus, but showed limited VFAs production, whereas alkaline pretreatment rapidly increased soluble EPS due to pH-induced cell disruption. Bioaugmentation achieved the highest total COD but yielded comparatively low soluble fractions. Following fermentation, HTP 170 °C consistently outperformed other treatments, maintaining elevated soluble COD and producing the highest acetate concentration. EPS analysis revealed extensive protein and polysaccharide degradation in thermal and bioaugmented systems, indicating active utilization during fermentation. Overall, the results demonstrate that targeted pretreatment strategies significantly enhance organic solubilization, EPS disruption, and VFAs yields, with thermal pretreatment showing the greatest potential to accelerate hydrolysis and acidogenesis. These findings provide valuable insights for optimizing the pre-methanogenic stages of AD and improving the efficiency of sludge treatment and resource recovery.

Processes doi: 10.3390/pr14111769

Authors: Yutong Wang Tao Li Can Yang Hua Chai Wangshui Hu Ping He Chenglin Wang Su Lyu

This paper explores the internal rock plugging rules induced by oily sludge profile control systems in oilfields. Three typical sludges including wastewater tank bottom sludge (WTBS), crude oil tank bottom sludge (CTBS) and floating scum sludge (FSS) are adopted. Combined with micro-CT scanning and digital core technology, this paper systematically investigates the pore–throat structure evolution and damage mechanism before and after sludge injection into rock cores. Key parameters such as plugging rate, average pore radius, throat radius, coordination number, shape factor, pore–throat ratio and pore–throat volume are quantitatively characterized macroscopically and microscopically, which reveal diverse damage modes and plugging mechanisms of the three sludges. The results indicate that pores of 10–50 μm are preferentially blocked by all sludges. CTBS causes the severest core damage with an average plugging rate of 79.67%, and the average coordination number decreases from 4 to 1, governed by the mechanism of adsorption diameter reduction and structural destruction. WTBS leads to uniform jamming of fine particles. Its average parameters change slightly, yet permeability declines due to broken critical throats. It follows the mechanism of uniform filling and weak adsorption with an average plugging rate of 56.75%, showing mild reservoir modification capacity. FSS causes moderate damage. Retained emulsion droplets trigger uniform slight shrinkage of pore throats under partial and overall selective filling mechanism, with an average plugging rate of 63.36% and favorable selective plugging performance. This study clarifies the inherent correlation between macroscopic damage and microscopic behaviors of oily sludge, offering microscopic theoretical references for differentiated management of sludge reinjection and oil displacement with composite sludge profile control agents.

Processes doi: 10.3390/pr14111771

Authors: Zhipeng Yu Xingyu Wang Tengrui Qu Ting Pan Kai Liu Siyan Hong Xiao Cen Zhenglong Li Zhanghua Yin Minjuan Wang

Buried-pipeline leakage poses significant safety risks, yet traditional CFD (Computational Fluid Dynamics) simulations are too slow for real-time diagnosis. This study integrates machine learning with interval sampling to develop a fast and interpretable prediction method. From 1.4 billion CFD-generated data points, 140 million representative samples were extracted via 1:10 interval sampling. Using 17 physical features as inputs, we trained and compared XGBoost, LightGBM, and a Multi-Layer Perceptron (MLP). The MLP model demonstrated exceptional performance (R2 (R-squared) = 0.9988, RMSE (Root Mean Square Error) = 0.0153), significantly outperforming the tree-based models (R2 ≈ 0.93). Three independent sampling runs confirmed its robustness (R2 coefficient of variation~0%). SHAP (Shapley Additive Explanations) analysis identified spatial coordinates and leak aperture as the most critical factors, while also revealing the nonlinear influence of soil particle size. This approach offers a high-precision, interpretable, and efficient surrogate model for buried-pipeline leakage warning systems.

Processes doi: 10.3390/pr14111770

Authors: Claire K. Sanders Taraka Dale Erika Y. Quezada Bruno C. Klein Sara L. Pacheco Nilusha Sudasinghe John McGowen Jessica Forrester

The development of large-scale microalgae growth for biofuel production is currently limited by the cost of biomass production. However, new approaches to infrastructure and cultivation practices are bringing the field closer to realization. Macronutrients in the cultivation media contribute significant costs, especially since their concentrations have not been optimized for specific strains and conditions. Environmental photobioreactors (ePBRs) were used to simulate cultivation under outdoor conditions, during which the nitrogen and phosphorus levels in the media were varied. The growth of two potential biofuel production strains, Picochlorum celeri and Tetraselmis striata, with varying nutrient inputs during summer and winter scripts, respectively, was studied. This study demonstrated that nitrogen and phosphorus in f/2 media could be reduced by more than 60% from the standard formulation, while maintaining growth rates in a semi-continuous harvesting approach. Experiments comparing the standard and reduced nutrient input concentrations were also conducted for both species in 820 L outdoor raceway ponds, in Mesa, AZ. P. celeri grown in these ponds in October had a growth rate of 10.6 ± 0.7 g/m2/day and 10.6 ± 0.3 g/m2/day for the standard and low-nutrient P. celeri ponds, respectively. T. striata grown in April–May had a growth rate of 16.6 ± 1.4 g/m2/day for the standard nutrient input ponds and 17.4 ± 1.1 g/m2/day for the low-nutrient input ponds, and in October 14.5 ± 0.6 g/m2/day for standard nutrient ponds and 14.4 ± 0.6 g/m2/day for low-nutrient ponds. These outdoor data therefore confirmed the indoor ePBR data. Techno-economic analysis shows that, if high growth rates can be attained at lower nutrient concentrations, a reduction of at least 60% in nutrient costs can be achieved. Such results highlight the importance of managing macronutrient media inputs, as these have a considerable contribution to biomass production costs in large-scale facilities. The analysis also points to the importance of maintaining high spent medium recycling rates in an industrial deployment, so as to minimize the losses of nitrogen and phosphorus compounds.

Processes doi: 10.3390/pr14111758

Authors: Julio A. Gutiérrez González Álvaro Ramírez Javier Llanos José Villaseñor Camacho Martín Muñoz-Morales

The circular valorization of biomass for sustainable energy recovery is a strategic priority in the transition toward low-carbon systems. In the last decade, anaerobic digestion (AD) has emerged as an efficient technology to produce an energetic vector to replace natural gas with biomethane and reduce waste; however, the hydrolysis of refractory fractions remains the main rate-limiting step. This study investigates an innovative electro-assisted pretreatment of biomass to promote the first rate-limiting hydrolysis step of refractory compounds in biomethane production. Lignocellulosic residues are employed not only as feedstock for the AD process but also as substrates in electrohydrolysis (EH) pretreatment using an Ir-Ta mixed metal oxide (MMO) anode coupled with advanced biomass-derived carbon felt cathodes. Two cathodes were functionalized with Phragmites Australis (PhA) hydrochars, untreated (PA) and KOH-activated (PA-KOH), to enhance the in situ generation of reactive oxygen species (ROS). Brassica napus (Bn) was chosen as the other biomass selected as a feedstock of AD, and was subjected to EH at varying energy inputs (500–5000 kJ·kg−1), evaluating structural and biochemical shifts. The results demonstrate that EH effectively modifies the biomass matrix; the PA-KOH-CF cathode exhibited good selectivity to degrade lignocellulosic structures, but higher biomethane production was achieved at 2500 kJ·kg−1 TS using PA-CF, reaching an increase of 52% compared with untreated samples. Kinetic analysis of the biomethane potential was performed using the modified Gompertz model. The model accurately captured the asymmetric sigmoidal transitions of methane production with different electrode configurations, and finally, energy balance assessment identified 2500 kJ·kg−1 TS as the optimal operational threshold. These findings suggest that an excess of applied energy is critical to the availability of soluble organic matter and the presence of refractory compounds that reduce efficiency. This electro-assisted approach offers a robust strategy for intensifying AD, aligning with circular bioenergy objectives.

Processes doi: 10.3390/pr14111768

Authors: Juan Pedro Elissetche Eduardo Troncoso-Ortega Luis Troncoso Carolina Puentes Rosa Alzamora Rafael Rubilar Vicente Hernández Carolina Parra-Fuentes

The wine industry generates large volumes of grape stalk residues that remain largely underutilized and are frequently disposed of by open-field burning, contributing to greenhouse gas emissions and the loss of biomass valorization opportunities. This study aims to evaluate the feasibility of producing single-layer particleboards from grape stalk particles (Vitis vinifera L.) bonded with a urea–formaldehyde resin, with a focus on their suitability for interior non-structural applications. Particleboards were manufactured at three target densities (550, 650, and 750 kg/m3) and assessed mainly for their physical and mechanical performance in relation to the requirements of EN 312. Internal bond strength showed a clear dependence on board density: panels produced at 650 and 750 kg/m3 met the minimum threshold for P2-type particleboards, whereas those produced at 550 kg/m3 did not comply with the standard. Thickness swelling decreased with increasing density, with only the highest-density boards fulfilling the reference criterion. Overall, the results indicate that grape stalk residues can be effectively converted into particleboards with adequate mechanical performance when manufactured at densities of at least 650 kg/m3. The study highlights the potential of this agro-industrial residue as a low-impact raw material for particleboard production, supporting circular bioeconomy strategies and development in wine-producing regions.

Processes doi: 10.3390/pr14111765

Authors: Yunpeng Zhang Qi Ma Jiahui Du Xinke Chang Xue Li Ti Yan Shijian Zhang Zhi Yang

Microseismic early warning for roof disaster in excavated coal roadways often suffers from low pertinence and a high false positive rate. This study establishes an intelligent early warning process based on unsupervised learning and a voting mechanism. True triaxial compression and drilling tests were conducted to characterize the acoustic emission responses of coal and rock during fracture. Using 720 h of field microseismic data from a high-gas mine in Shanxi, high-weight precursor features were extracted from time–frequency indicators. Kernel principal component analysis (KPCA) was used to optimize the indicator system, and 49 indicators with weights above 0.08 were selected as model inputs. Five unsupervised clustering algorithms were integrated to establish an ensemble decision-making early warning model. The results show that the model eliminates the drawbacks of single algorithms, achieves accurate roof disaster warning, and correctly distinguishes disaster events from non-disaster high-energy events. The false positive rate is zero on the 720 h field dataset, and the reliability of early warning is significantly improved. This study enhances the reliability of mine roof microseismic warning, enriches roof disaster prediction theories, provides a complete intelligent early warning process for mine roof disaster, and offers important references for deep mining dynamic disaster warning research.

Processes doi: 10.3390/pr14111767

Authors: Antonina Kalinichenko Dmytro Marchenko Vasyl Hruban Vira Hovorukha

The article presents the results of experimental investigations and regression-based analysis on the influence of a water injection system on the fuel efficiency and performance of diesel engines used in agricultural machine–tractor units. The need to improve fuel economy and operating efficiency is driven by increasing energy costs and the growing demand for more efficient agricultural machinery. The study focuses on the application of water injection into the intake manifold as a method for improving fuel consumption and engine operating performance under laboratory and field conditions. Experimental investigations were carried out on a Deutz 1000.3 W diesel engine under laboratory and field conditions. The engine was tested on a dynamometer, and field tests were performed using a Deutz-Fahr Agrolux 80 (SDF Group, Treviglio, Italy) tractor powered by the tested Deutz engine and coupled with an Amazone D9-20 Super (AMAZONEN-WERKE H. DREYER SE & Co., KG, Hasbergen-Gaste, Germany) seeder. The seeder was used as a trailed agricultural implement and did not have its own engine. The optimal water-to-fuel ratio was found to be 27–32%, ensuring a balance between increased engine power and reduced fuel consumption. The use of water injection reduced fuel consumption by 10–15%, increased effective engine power by up to 19%, and improved traction performance under field conditions. The novelty of this study lies in the adaptation and experimental evaluation of intake water injection for an agricultural diesel engine operating as part of a machine–tractor unit. Particular attention was paid to the relationship between the water-to-fuel ratio, fuel consumption, engine performance, and traction characteristics under laboratory and field conditions. The results demonstrate that water injection provides a cost-effective and technically feasible solution for improving fuel economy and operating performance of agricultural diesel engines without requiring significant modifications to existing designs. Potential environmental benefits may be associated with reduced diesel fuel consumption. However, emissions were not the main experimental focus of the present study and should be investigated separately in future work.

Processes doi: 10.3390/pr14111764

Authors: Yangsong Yang Jianlin Hua Ronghao Chen Weijia Huang

Against the backdrop of the global energy transition and decarbonization imperative targets, improving the efficiency of conventional energy systems while simultaneously reducing carbon emissions has become a pressing challenge. To address the widespread problem of insufficient waste heat utilization in combined cooling, heating, and power (CCHP) systems, this study proposes a novel low-carbon-emission CCHP system coupled with heat pump (HP) technology and a monoethanolamine (MEA)-based carbon capture and storage (CCS) subsystem. The HP unit enables cascaded recovery and temperature upgrading of low-grade waste heat from both the flue gas and the CCS regeneration column. A comprehensive five-dimensional evaluation framework—covering energy, exergy, life cycle environmental assessment, economic and exergoeconomic analyses—is established and benchmarked against a conventional low-carbon CCHP reference system. Thermodynamic results show that HP integration raises the overall energy efficiency from 74.25% to 81.22% and the waste heat recovery rate from 73.59% to 89.85%, while simultaneously reducing exergy losses by 365.06 kW and elevating exergy efficiency from 53.95% to 65.07%. Economic analysis reveals that the unit energy production cost decreases from 0.033 to 0.031 $/(kW·h), despite a marginal increase in unit power generation cost. Sensitivity analysis identifies operating hours and interest rate as the dominant cost drivers. Exergoeconomic analysis pinpoints the turbine, the CCS subsystem, and the compressor as contributing 67.02%, 17.11%, and 8.17% of the total exergoeconomic losses, respectively, identifying them as the primary targets for future optimization. These findings provide a theoretical foundation and engineering guidance for the development and deployment of high-efficiency, low-carbon multi-generation energy systems.

Processes doi: 10.3390/pr14111766

Authors: Aliya Gabdelfayazovna Safiulina Ismagil Shakirovich Khusnutdinov Dina Nailevna Khairullina Suleiman Ismagilovich Khusnutdinov Irina Nikolaevna Goncharova Binqiao Ren

Currently, there is no existing methodology within commercially available software packages for accurately simulating the gradual evaporation of the aqueous phase in batch thermomechanical dehydration processes involving highly stable water-hydrocarbon emulsions. This limitation constitutes a significant obstacle to the widespread industrial implementation of a promising approach for liquid hydrocarbon waste disposal, which relies on the evaporation of the aqueous phase under intensive stirring conditions, ultimately producing a hydrocarbon product with residual water content. In this study, the widely used Aspen HYSYS V12 software was employed to model these processes. The primary objective was to identify the most appropriate thermodynamic model accurately describing vapor–liquid phase transitions during the boiling of the aqueous phase in highly stable water–hydrocarbon emulsions, with water content ranging from 2 to 60% by weight. The modeling of the gradual boiling process was divided into several sequential stages, each representing a single evaporation step. The initial feedstock temperature was set at 90 °C, with subsequent stages involving temperature increments of 5 °C until the residual water content in the product fell below 0.5% by weight. Four thermodynamic models were evaluated for their ability to predict phase equilibria: Peng–Robinson, Wilson, UNIQUAC, and NRTL. It was observed that the Peng–Robinson model poorly describes the dehydration process, as it predicts water evaporation only at 100 °C, which contradicts experimental evidence indicating that evaporation occurs over a broader temperature range. The Wilson model significantly overestimates boiling points, reaching values up to 290 °C. Although the UNIQUAC model accurately reflects the process at higher water contents, it results in elevated energy consumption, necessitating substantial superheating of the feedstock up to 220 °C. The NRTL model provided the best correlation (among studied thermodynamic models) with experimental data, providing an average relative deviation of 3.68% and effectively capturing the two-stage evaporation mechanism: initial removal of free water at 100–110 °C, followed by bound moisture evaporation at temperatures approaching 160 °C. Vaporization rates were also examined across all models. The Peng–Robinson approach predicted the highest vaporization peaks but was the least representative of actual process conditions. Notably, in the NRTL model, the peak vaporization rates were 1.9 to 2.7 times higher than those estimated using the UNIQUAC and Wilson models. This parameter is critical for the optimal selection and design of subsequent condensation equipment. Based on these findings, the NRTL thermodynamic model is recommended for the industrial-scale implementation of thermomechanical dehydration processes involving heavy hydrocarbon feedstocks, given its accuracy in modeling phase transitions and the temperature-dependent vapor generation rates derived from sequential equilibrium flash calculations.

Processes doi: 10.3390/pr14111763

Authors: Braulio Cervantes-Paz María Zenaida Saavedra-Leos Janet María León-Morales Héctor Reynoso-Ponce Alejandro Rocha-Uribe Laura Araceli López-Martínez

Pumpkin (Cucurbita maxima) is an important vegetable in traditional agricultural systems worldwide, including Mesoamerica. Recently, pumpkins have gained global attention for their substantial nutritional value and bioactive compounds; however, their seeds are frequently discarded as waste. These underutilized seeds represent a promising alternative flour source for functional baked goods, such as pancakes. We aimed to optimize the formulation of pancakes made from pumpkin seed flour using a mixture experimental design (MED) and to evaluate the physicochemical, bromatological, and sensory characteristics of the final product. The experimental design investigated various formulations comprising three flour types: shell-less pumpkin seed flour (SL), pumpkin seed flour with shell (WS), and wheat flour (WF). The results indicated that pancakes formulated with WS and SL contained higher levels of protein, amino acids, and fatty acids compared to pancakes control made only with WF. Furthermore, these formulations achieved higher consumer acceptability in sensory evaluations. These findings demonstrate that formulations incorporating SL (moisture content = 21; protein = 19; sensory acceptance = 7) and WS water activity = 0.88; protein = 19; fat = 26; and fiber = 10), optimized through MED, provide superior nutritional quality and sensory acceptance. The formulation with 0.5 of WF and 0.5 of SL exhibited the best health attributes and functional characteristics.

Processes doi: 10.3390/pr14111762

Authors: Ming Zhang Wei Liu Yunhai Wang Kai Zuo Tao Xu Guoqing Han Cheng Wang Jinyang Hu Shuai Zhang

Offshore reservoirs are commonly characterized by complex geology, constrained operations, and high per-well investment. Improving economic performance while maintaining deliverability is therefore a pressing need during field development. By combining multilateral wellbores with staged hydraulic fracturing, complex-structured wells can markedly enhance well–reservoir connectivity; however, for fishbone-type complex-structured wells, published studies still provide limited case-based discussion on how branch-junction loss, completion staging, fracture parameters, and the economic metric jointly affect the final design outcome. In this study, a semi-analytical productivity model for complex-structured fractured wells is developed, accounting for a multi-scale coupling among the reservoir, fractures, and the wellbore. The wellbore and fractures are discretized to quantify the contribution of each completion stage and fracture element to overall productivity. An economic metric with net present value (NPV) as the objective function is then introduced, and a genetic-algorithm-based joint optimization method is established for completion staging parameters and fracture-geometry parameters, enabling an automatic search for the key design variables. The model is validated against water–electric analogy experiments and a field case, demonstrating good predictive accuracy. Case studies show that, with a reasonable parameter configuration, complex-structured fractured wells can significantly increase the cumulative oil production and the NPV under a limited increase in cost; the optimized NPV is improved by approximately 20.2%, illustrating the potential interaction among completion staging, fracture parameters, and the NPV metric under the studied reservoir and economic conditions.

Processes doi: 10.3390/pr14111760

Authors: Trajce Trajkov Stanislava Todorova Nina Kaneva

Cephalexin is a widely used antibiotic frequently detected in hospital wastewater and aquatic environments near pharmaceutical facilities, where its persistence contributes to the spread of antibiotic resistance. Mechanically driven advanced oxidation processes, including piezocatalysis and tribocatalysis, represent sustainable alternatives for pollutant removal because they operate without external light or heat sources. In this study, ZnO catalysts with controlled morphologies were synthesized via sol–gel and mechanochemical methods using different solvents and activation times (1 and 5 h). The influence of structural characteristics, surface area, and friction conditions on catalytic performance was systematically evaluated. The results demonstrated that tribocatalytic efficiency strongly depends on stirring rate and reactor material, with PTFE systems exhibiting superior performance. Mechanochemically activated ZnO (1 h) showed the highest degradation efficiency due to optimized defect density and surface accessibility. All catalysts exhibited high stability, while radical scavenging experiments identified superoxide radicals as the primary reactive species in the degradation process.

Processes doi: 10.3390/pr14111761

Authors: Xiaopei Yuan Ruojin Wang Dewu Wang Ruofeng Xu Xuefang Gao Bin Zhao Shaofeng Zhang

To improve the operational stability and mass transfer performance of fluidized bed reactors under dynamic conditions, this study examines radial particle velocity distributions at different bed cross-sections using a dual-probe measurement method across a range of rocking frequencies and superficial gas velocities. The analysis identifies the dominant influence of additional inertial forces generated by rocking motion, including the Euler force and Coriolis force, in determining the time-averaged flow structure, leading to the development of a spatiotemporally averaged flow field model and clarification of the interaction mechanisms between these forces. Results indicate that the flow field exhibits two representative macroscopic patterns governed by the interplay between inertial forcing and particle response characteristics: at low frequencies, the slowly varying Euler force combines with gravity to produce a coherent large-scale single-circulation structure, whose stability is sustained under higher gas velocities due to reduced internal energy dissipation associated with stronger drag; at high frequencies, the Coriolis force promotes structural division while the rapidly oscillating Euler force introduces disturbances, resulting in the formation and persistence of double or multi-circulation flow structures under their combined action.

Processes doi: 10.3390/pr14111759

Authors: Aline Raquel Reis Marcolino Anna Rafaela Cavalcante Braga

Spirulina (Limnospira) is a cyanobacterium rich in bioactive compounds, making it a sustainable and innovative biotechnological ingredient for the cosmetics industry. It meets the demand for non-animal-derived, multifunctional products for skin and hair care. In this study, Spirulina biomass was incorporated into shampoo (0.01%) and emulsion (5%) formulations, which, along with their respective controls, were subjected to cosmetic stability tests. Color, pH, and viscosity were analyzed at the initial time (T0) and after 24 h, 30, 60, and 90 days, with samples exposed to different storage conditions, including oven incubation, sunlight exposure, refrigeration, and shelf storage, to simulate diverse conservation environments. Microbiological parameters were assessed, and all samples complied with the specifications required for cosmetics. Antioxidant activity was also measured at baseline and after 90 days of storage. Results showed that incorporating Spirulina biomass, even at low concentrations, significantly enhanced antioxidant activity in both shampoo and emulsion formulations compared with controls. After 90 days, the samples maintained their stability in terms of appearance, color, odor, pH, and viscosity under sunlight, refrigeration, and shelf storage conditions. In contrast, samples exposed to elevated temperatures (45 °C) exhibited changes in color, pH, and viscosity. These findings demonstrate the feasibility of incorporating Spirulina biomass into cosmetic shampoo and emulsion bases, highlight potential changes during storage, and provide guidance for developing novel cosmetics that incorporate Spirulina as an ingredient.

Processes doi: 10.3390/pr14111757

Authors: Yufei Fu Yang Cheng Peilin Gong Songyuan Cao Dongbo Song Gaohui He

Due to their higher installation position and smaller diameter compared to conductors, DC overhead ground wires are more susceptible to severe icing during cold waves. To investigate the icing growth characteristics of ultra-high voltage (UHV) DC ground wires under the coupled effect of flow and electric fields, this study considers the unique operational conditions of UHV DC ground wires. Based on the physical processes of charged droplet motion, flow-around, collision, and freezing around the ground wire, a numerical model for simulating icing under the coupled flow-electric field interaction is established. The influence of factors such as wind speed, droplet size, and icing morphology on icing development under the coupled field is numerically analyzed. Furthermore, observations of icing morphology on UHV ground wires under natural conditions were conducted. The results indicate that under icing conditions, charged droplets of different sizes exhibit significant differences in trajectory deviation during flow-around and collision with the ground wire, with larger droplets being more significantly affected by the electric field force. Under the influence of the electric field, the local droplet collision coefficient on the ground wire surface can increase by 3.4% to 128.9%. Compared to uncharged conditions, icing coverage under charged conditions extends from the windward side to the leeward side, and the icing rate increases accordingly. Natural observations reveal that icing on the ground wire surface under the DC electric field often forms protruding ice tips, which enhance electric field concentration, leading to increased local droplet collision coefficients and icing rates. This, in turn, further promotes the formation of irregular and rough ice accretion. The findings of this study provide technical insights for predicting and simulating icing on UHV DC ground wires.

Processes doi: 10.3390/pr14111755

Authors: Rabiatul Adawiyah Ali Nik Nor Liyana Nik Ibrahim Hon Loong Lam

The journal Processes retracts the article titled “Conversion Technologies: Evaluation of Economic Performance and Environmental Impact Analysis for Municipal Solid Waste in Malaysia” [...]

Processes doi: 10.3390/pr14111756

Authors: Rita do Nascimento Brenda Santos Ana Pereira Sueli Rodrigues

The demand for functional foods, particularly probiotics, has increased substantially in recent years. The search for plant-based milk alternatives (PBMA) has also risen, influenced by factors such as lactose intolerance, allergies, veganism, and environmental sustainability. Cashew nut kernels have high nutritional value, and are a suitable alternative for preparing plant-based beverages. Therefore, this study aimed to develop a potentially probiotic cashew nut-based beverage fermented by Lacticaseibacillus casei NRRL B-442. The fermented cashew nut-based beverage was prepared, and its stability was evaluated over a 42-day refrigerated storage period (4 °C). Various parameters were monitored, including pH, viability, and concentration of lactic acid, in addition to sugars. The survival rate of microorganisms following simulated gastrointestinal digestion was also determined. Sensory analysis included word association, hedonic scale, and CATA tests. During fermentation, the microorganism consumed glucose, leading to the production of lactic acid. The fermented drink was stable throughout the refrigerated storage period, with a final viable cell count greater than 12 log CFU/mL. After in vitro digestion, probiotic survival rates were higher than 73% in all the samples analyzed. The sensory analysis showed positive consumer acceptance. No statistically significant difference in overall hedonic acceptance was observed between the CNB sweetened with sucrose and sucralose, although both differed from the commercial fermented milk control in several sensory attributes. These results suggest that the cashew nut-based matrix is a promising alternative for developing functional plant products. This study effectively produced a probiotic beverage from cashew nut kernels with functional potential, providing a new product option for interested consumers.

Processes doi: 10.3390/pr14111754

Authors: Shanchao Gao Xu Geng Xiaobo Zhang Yanhui Zhang Zhe Jiang Zhenghong Zhao

In this study, the thermodynamic conditions governing TiC formation were systematically investigated based on Gibbs free energy and interaction parameter theory. The effects of temperature and furnace atmosphere on interaction parameters were explicitly incorporated, enabling an improved thermodynamic description of TiC formation under realistic blast furnace conditions. Furthermore, compared with conventional two-dimensional equilibrium analyses, a three-dimensional Ti-C-temperature thermodynamic precipitation surface was established to quantitatively evaluate the effects of temperature, titanium content, and carbon content on TiC precipitation behavior. The results indicate that titanium is the dominant controlling factor for TiC formation, while carbon plays a secondary synergistic role. Compared with dissolved carbon, solid carbon provides more favorable thermodynamic conditions, suggesting that TiC preferentially forms via interactions with high-activity carbon sources such as coke or refractory materials. Based on the modified thermodynamic framework and boundary conditions, a quantitative precipitation criterion was established as 100 × w[Ti]% + w[C]% ≥ 10, which ensures TiC precipitation prior to molten iron solidification under representative blast furnace hearth conditions. The proposed criterion provides a practical guideline for titanium addition and carbon regulation in blast furnace ironmaking and improves the thermodynamic prediction capability for titanium-bearing protective phase formation in complex high-temperature metallurgical environments.

Processes doi: 10.3390/pr14111753

Authors: Haixiao Lin Ying Jiang Shujie Li Wei Li Desheng Zhu Jiarui Chen Teng Teng Yi Xue Zhengzheng Cao

To investigate the deterioration of compressive property of traditional concrete in a high-temperature environment, uniaxial compression tests were conducted on concrete at various high temperatures. Combined analytical techniques—scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric-mass spectrometry (TG-MS)—were used to analyze the degradation mechanism. The experimental results indicate that high temperature has a strong temperature-dependent effect on concrete’s compressive strength. As temperature increases (400 °C, 600 °C, 800 °C), concrete’s compressive strength decreases. These decreases are 27.52%, 56.6%, and 80.76% relative to room temperature, respectively. This phenomenon is attributed to the direct link between concrete’s microstructure and its macroscopic mechanical properties—driven by thermal stresses generated during heating and the decomposition of cement hydration products. Temperatures above 400 °C trigger microcrack formation, and microcracks propagate more rapidly with increasing temperature. At temperatures further increasing to 600 °C, fewer cementitious materials are left decomposable; even stable calcium carbonate starts to decompose. At temperatures of 800 °C or more, decarburization occurs, rendering the concrete microstructure loose and porous. Partial separation of aggregates from the paste causes a near-total loss of compressive strength.

Processes doi: 10.3390/pr14111752

Authors: Jianbin Ci You Yu Tao Li Zhenting Sun Jingfu Tian Ming Dong Qiang Ma Shiming Wang Jingshan Mo

With the expansion of transmission networks and the increasing penetration of inverter-based resources (IBRs), fixed offline distance-protection settings face increasing difficulty in balancing selectivity, sensitivity, and operating speed. This problem is particularly evident in Zone III remote-backup protection, where conservative load-avoidance settings may create blind zones. This paper proposes an adaptive three-zone distance-protection setting method based on explicit sensitivity constraints and a disturbance-domain model. The method has two main features. First, online recalculation is restricted to the local disturbance domain affected by topology changes, thereby avoiding network-wide recomputation. Second, Zone II and Zone III settings are determined by a constrained model that incorporates real-time branch coefficients, load impedance, sensitivity requirements, and downstream coordination limits. A fallback mechanism is also included to maintain security under data loss or abnormal measurements. In a 220 kV case study, the proposed method increases the Zone II sensitivity coefficient from 1.92 to 1.95 and the Zone III remote-backup sensitivity coefficient from 0.83 to 1.35. Additional tests under high-resistance faults, measurement errors, volatile load, and inverter-based resource integration show that the method preserves selectivity while reducing backup protection blind zones. The disturbance-domain strategy also reduces the average recalculation time from 820 ms to 18 ms in the tested regional setting-calculation scenario.

Processes doi: 10.3390/pr14111751

Authors: Tao Zhang Zhigang Zhang Zhang Jiang Jing Zhu Chunxiu Huo Zhongqing Yang

Ventilation air methane (VAM) discharged from coal mines is considerable in volume, causing serious environmental pollution and energy resource waste. The methane concentration of raw VAM is generally lower than 0.3%, which greatly limits its efficient utilization. Blending low-cost solid fuels with VAM for regenerative oxidation is a practical and promising strategy to overcome the technical bottlenecks of VAM resource recovery. Clarifying the gas–solid two-phase flow behaviors inside millimeter-scale regenerative microchannels is critical for optimizing the process parameters and structural design of regenerative oxidation devices. In this work, numerical simulations are conducted using ANSYS Fluent 2022 R2 software to systematically explore the flow evolution characteristics and corresponding influencing factors of gas–solid two-phase flow in millimeter-scale microchannels to investigate three key objectives: (1) reveal the flow evolution characteristics of gas–solid two-phase flow in millimeter-scale microchannels along the flow direction; (2) quantify the effects of particle size and inlet velocity on particle deposition rate and deposition velocity; and (3) propose optimal operational parameter ranges to avoid microchannel blockage and improve particle transport performance. Along the flow direction, the near-wall velocity gradient gradually declines with the flow distance, while the thickness of the boundary layer grows continuously. Both particle deposition rate and deposition velocity are positively correlated with particle size. At an inlet velocity of 2 m/s, once the particle size exceeds 60 μm, the deposition rate and velocity rise markedly, and the particle outflow probability decreases significantly. For a fixed particle size, increasing flow velocity reduces both deposition rate and deposition velocity, which enhances the transport ability of pulverized coal particles and weakens wall adhesion. When the flow velocity is lower than 2.5 m/s, the outlet deposition rate exceeds 60%, and the particle deposition velocity rises sharply. Accordingly, maintaining flow velocity above 2.5 m/s and controlling particle size below 60 μm can effectively inhibit rapid particle deposition, improve particle transport performance, and avoid microchannel blockage. This study provides a theoretical basis and parameter reference for the structural and operational optimization of horizontal microchannels in pulverized coal-blended VAM regenerative oxidation systems.

Processes doi: 10.3390/pr14111750

Authors: Yu Liu Xuezhi Zhang Chuanchao Zhao Yudong Mao Kaimin Yang Shengze Lu Jiying Liu

The post-combustion carbon capture process with monoethanolamine/piperazine (MEA/PZ) blends encounters notable modeling and optimization challenges. These arise from strong thermodynamic–kinetic nonlinear coupling, as well as limited availability of high-quality experimental data. To address this, we propose a machine learning and multi-objective optimization strategy driven by physicochemical features. By extracting explicit physical features and embedding physicochemical constraints into data-driven models, this study evaluated the predictive performance of three distinct algorithms based on wet-wall column experimental data. These algorithms included natural gradient boosting (NGBoost), sure independence screening and sparsifying operator (SISSO), and gaussian process regression (GPR). Subsequently, an optimization problem aimed at minimizing PCO2* and maximizing kg′ was formulated. The multi-objective beluga whale optimization (MOBWO) algorithm was then employed for global optimization and benchmarked against the traditional non-dominated sorting genetic algorithm II (NSGA-II). Results indicate that the Gaussian process regression (GPR) model performed best when it was enhanced by physicochemical features and optimized via Bayesian hyperparameter tuning. It achieved R2 values of 0.989 and 0.953 for PCO2* and kg′, with average absolute relative deviations (AARDs) kept below 15.7% and 12.2% respectively. Feature importance analysis validated the underlying physical laws. Specifically, temperature dictates thermodynamic equilibrium, while CO2 loading limits mass transfer kinetics. In the optimization phase, MOBWO outperformed NSGA-II by generating a more uniformly distributed Pareto front. Decision-making analysis further identified three typical operating regimes encompassing kinetics-dominant, thermodynamics-dominant, and comprehensive equilibrium conditions. This framework provides a robust paradigm for small-sample modeling and optimization in complex chemical processes.

Processes doi: 10.3390/pr14111749

Authors: Wang Qian Xinyu Wang Qiang Wang Yang Hao Xiaojuan Zhao Yijie Zhang

This study investigated the effects of freeze–thaw pretreatment on the solar hot-air drying behavior, moisture migration, and microstructure of Mongolian Astragalus (Astragalus membranaceus var. mongholicus) slices. An L9 orthogonal design with slice thickness, diameter, air velocity, and drying temperature was used; drying kinetics, water-state distribution, and surface morphology were assessed by thin-layer models, apparent effective moisture diffusivity, LF-NMR, and SEM. The drying process showed no obvious constant-rate period and was mainly characterized by a falling-rate stage, indicating that dehydration was controlled by internal moisture migration. Freeze–thaw pretreatment redistributed the initial water fractions but did not uniformly accelerate drying; the longest drying time decreased from 130 to 100 min, showing a condition-dependent effect. Slice thickness was the dominant factor affecting the average drying rate. The preferred conditions were 1–3 mm thickness, 8–11 mm diameter, 1.0 m·s−1 air velocity, and 50 °C for the control group, and 1–3 mm thickness, 11–14 mm diameter, 1.5 m·s−1 air velocity, and 50 °C after freeze–thaw pretreatment. The Midilli model best fit the moisture-ratio data, and the apparent effective moisture diffusivity remained on the order of 10−9 m2·s−1. LF-NMR showed that endpoint residual moisture was mainly bound water, with free water almost completely removed. SEM observations showed a looser surface with more visible pores and cracks after freeze–thaw pretreatment. Overall, freeze–thaw pretreatment mainly affected solar hot-air drying by regulating moisture migration, with effects depending on process conditions.

Processes doi: 10.3390/pr14111748

Authors: Chengming Wu Jie Ma Hui Wan Guofeng Guan

To overcome the low heat-transfer efficiency on the seawater side of the intermediate fluid vaporizer (IFV), a triangular inner-finned heat-transfer enhancement tube suitable for low to medium-flow-velocity conditions was designed. The influence of triangular internal fins’ axial spacing, height, radial arrangement number, and inclination angle on the flow and heat transfer characteristics inside the tube was numerically investigated. The tube performance was evaluated and optimized by performance evaluation criteria (PEC). The results indicated that triangular internal fins induced vortex structures, which disrupted the boundary layer, thereby enhancing momentum and energy exchange between the hot fluid within the boundary layer and the cold fluid outside it. Heat transfer was improved with reduced fin distance, increased height, and increased the number of radial arrangements. The optimal comprehensive performance was achieved at an inclination angle of 75°. The Nusselt number (Nu) increased by 66.02%, the friction factor (f) increased by 162.23%, and PEC reached up to 1.203 when Re was 9545. The results provided a theoretical reference for the structural optimization of efficient heat-exchange tubes.

Processes doi: 10.3390/pr14111747

Authors: Ivana Karabegović Sandra Stamenković Stojanović Stojan Mančić Kristina Cvetković Marko Malićanin Dani Dordevic Bojana Danilović

This review synthesises current knowledge on five non-conventional technologies—high-power ultrasound, microwave treatment, pulsed electric fields, high hydrostatic pressure, and microbe-driven precision enology. These technologies have been applied at various stages of wine production, from pre-fermentative maceration to microbial stabilisation and ageing, with the aim of enhancing wine quality, processing efficiency, and stability. Reported achievements include faster and more selective extraction of colour and flavour compounds, improved clarity and chromatic intensity, and more consistent fermentation performance. Specifically, ultrasound treatment enhances phenolic and aromatic extraction through cavitation, accelerating maceration and improving colour and flavour complexity, while microwave treatment rapidly heats grape tissues via dipole rotation and ionic conduction, promoting pigment and aroma release and reducing fermentation or ageing time. Pulsed electric fields induce electroporation of grape cells, facilitating anthocyanin and tannin extraction, whereas high hydrostatic pressure stabilises finished wines by inactivating spoilage microorganisms and enzymes while preserving freshness, aroma, and sensory balance. Finally, microbe-driven precision enology provides a promising approach to producing distinctive wines with regional identity, representing an emerging experimental trend. Recent studies demonstrate that combining these technologies with established enological practices can result in measurable improvements in wine quality. The findings summarised in this review are of great importance for wineries aiming to enhance microbial control, reduce sulphur dioxide dosage in line with the growing demand for low-additive wines, shorten production time, and support more efficient and sustainable winemaking.

Processes doi: 10.3390/pr14111743

Authors: Xiaoyou Du Xiaolong Xiang Weitao Zhu Jifei Yu Guoqing Han Wenbo Jiang

Offshore high-water-rate gas wells can often sustain stable production for a considerable period after liquid first appears at the wellhead. Unlike conventional onshore gas wells with relatively low liquid production, these wells can remain in stable production during the middle and late production stages even when the gas velocity in the wellbore has fallen far below the critical value predicted by conventional liquid-carrying criteria. Under such conditions, the wellbore flow pattern commonly shifts from annular mist flow to churn flow and slug flow, and liquid transport becomes governed by a dynamic balance jointly controlled by pressure differential and gas entrainment. As a result, conventional critical liquid-carrying theory alone is no longer sufficient for accurate production state identification. To address this issue, this study proposes a production state identification method for offshore high-water-rate gas wells based on dynamic pressure profile calibration and nodal analysis. In this method, the wellbore pressure profile serves as the key link between outflow capacity and production state evaluation. Measured data from flowing pressure tests are used to calibrate the pressure profile within the selected multiphase flow correlation by introducing two calibration coefficients, namely the liquid holdup calibration coefficient and the two-phase friction calibration coefficient. Gaussian process regression is then applied to model the temporal evolution of the calibration coefficients, generate their fitted trajectories, and predict their values at the next time step. By using the predicted calibration coefficients to recalibrate the pressure profile, dynamic calibration of the wellbore pressure profile is achieved. Field applications to four offshore high-water-rate gas wells show that the calibrated pressure profiles are in closer agreement with the measured pressure points. The accuracy of production-state identification is also significantly improved, and the gas production rates calculated from calibrated nodal analysis are closer to the values reported in daily production records than those obtained before calibration. These results demonstrate that the proposed method effectively improves both wellbore pressure profile prediction and production-state identification for offshore high-water-rate gas wells. The study provides a practical method for production state evaluation and production management of offshore high-water-rate gas wells during the middle and late stages of field development.

Processes doi: 10.3390/pr14111746

Authors: Chengyuan Wang Ming Luo Shaolong Zhang

As thermal power units in China shift toward serving as flexible regulation sources in new-type power systems, accurately assessing the axial thrust of steam turbine regulating stages under off-design conditions has become critical. This paper employs numerical methods to investigate the axial thrust characteristics and nozzle structural optimization of the regulating stage under off-design conditions (VWO, THA, 75% THA, 50% THA). Steady-state results reveal significant deviations in the interstage hub forces predicted by 3D simulations compared with those from the conventional 1D formula under partial admission, prompting a correction. Unsteady results show that reducing the partial admission degree intensifies flow unsteadiness, increasing rotor blade axial force fluctuation from 1175 N (VWO) to 2057 N (50% THA). In terms of structural optimization, compared with not increasing the nozzle angle, increasing the nozzle angle by 2° reduces the total axial force on the regulating stage by 7.3%; compared with not extending the inlet guide arc segment, extending its length by 40 mm increases the axial force on the rotor blade by 1.6%, but decreases the maximum amplitude from 323.9 to 249.9. Based on these findings, the optimization direction for the nozzle structure is proposed.

Processes doi: 10.3390/pr14111745

Authors: Tong Wu Junjie Huang Qihao Qian Quanhou Li

To address the problems of strong vertical heterogeneity in thin interbedded reservoirs of the N block in Daqing Oilfield, the complex coupling between porosity and permeability, and the difficulty of conventional single-parameter inversion methods in balancing local details with global geological background, a joint inversion method for porosity and permeability based on GeoFE-PPNet and logging imaging tensors is proposed. Using conventional logging curves, including GR, RT, RHOB, NPHI, DT, and PE, the method constructs a logging imaging tensor by integrating multi-channel responses with shale constraints and extracts intra-layer textural features through local encoding. Meanwhile, sequence decomposition and frequency enhancement are introduced to capture vertical trend variations and high-frequency non-stationary responses of the reservoir. On this basis, geological constraint fusion and dual-task collaborative prediction are employed to achieve joint inversion of porosity and permeability. Experimental results show that the proposed method achieves favorable inversion accuracy and cross-well generalization under complex reservoir conditions, with a porosity R2 of 0.931, a permeability R2 of 0.887, and an overall accuracy of 90.74%. Ablation and noise robustness experiments further demonstrate the effectiveness of the logging imaging tensor, frequency enhancement, geological constraints, and dual-task collaboration in improving model performance. The study indicates that the proposed method can more accurately characterize the vertical variation in reservoir physical properties and provides a new technical approach for fine reservoir evaluation and intelligent log interpretation.

Processes doi: 10.3390/pr14111744

Authors: Peihua Liu Wenlong Xu Qin Yang Xiaochun Zhao Zhaolin Li Zishu Li Zheng Fan

Gas-phase sensors suffer from non-linear drift and range-precision conflicts, while the detection of dissolved H2S in the oil phase relies on discontinuous, offline chemical analysis. To address these challenges, this study proposes a dual-output soft sensing model based on a Particle Swarm Optimization-Extreme Learning Machine (PSO-ELM). Unlike conventional single-output PSO-ELM applications, the proposed framework jointly performs gas-phase sensor drift correction and oil-phase dissolved H2S estimation within a unified soft-sensing structure. By integrating gas sensor array signals with oil-phase process parameters, the model utilizes PSO to globally optimize the input weights and biases of the ELM, effectively overcoming the local minima and overfitting issues inherent in traditional neural networks. Field sampling results showed that the proposed model achieved high predictive accuracy, with coefficients of determination of 0.9949 for gas sensor drift correction and 0.9967 for oil-phase soft sensing. Comparative analysis reveals that the PSO-ELM significantly outperforms Standard ELM, RBF-ELM, and GA-ELM, reducing the Mean Squared Error by approximately 39.7% compared to GA-ELM. Furthermore, 5-fold cross-validation confirms the model’s robustness (R2 average of 0.9810), indicating its potential for real-time hydrogen sulfide monitoring in complex oilfield production environments.

Processes doi: 10.3390/pr14111742

Authors: Jiabao Wang Qi Wang Zhibo Zhang Zhiming Bai

Acidic mine water generated during underground CO2 sequestration and sulfide oxidation can alter the pore-fracture structure of coal, and threaten the stability of abandoned mine spaces. However, the mechanism through which acidic environments influence the deterioration of coal remains insufficiently understood. In this study, uniaxial compression experiments were conducted on coal samples treated with solutions with different pH values, and acoustic emission (AE) monitoring technology was used to characterize fracture activity and damage evolution during loading. A quantitative model linking acidity to the mechanical behavior of coal was established by integrating fractal theory with damage mechanics. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were further employed to reveal the microstructural and mineralogical mechanisms of coal deterioration. The results show that acidic environments significantly degrade the mechanical properties of coal samples. With decreasing pH, peak stress and elastic modulus of the selected representative sample progressively decrease, and the failure mode becomes increasingly fragmented and dispersed. At pH = 1, the degradation of peak stress and elastic modulus reaches 73.01% and 49.38%, respectively. Increasing acidity also enhances AE activity during loading and increases the correlation dimension, indicating greater crack complexity and instability. On this basis, the proposed quantitative model accurately describes the transformation process of coal samples from microscopic damage to macroscopic mechanical degradation induced by acidity. SEM and XRD results further show that stronger acidity promotes pore enlargement, crack interconnection, mineral dissolution, secondary mineral formation, and weakening of cementation, revealing the physical essence of the multi-scale damage and degradation of coal samples. The findings can provide a theoretical basis for assessing coal stability in acidic environments and ensuring the safe storage of CO2 in abandoned mines.

Processes doi: 10.3390/pr14111741

Authors: Yu-Hsien Chen Yuh-Ming Ferng

In contrast to conventional upward-facing heating, downward-facing surfaces exhibit distinct bubble dynamics and opposing buoyancy forces, presenting a challenge in terms of a boiling characterization that is difficult to capture experimentally or numerically. This study examines the performance of computational fluid dynamic (CFD) simulations in predicting subcooled downward-facing boiling heat transfer by comparing the simulation results with experimental observations under various correlation combinations. Grid Convergence Index (GCI) analysis was conducted to determine the appropriate grid resolution, ensuring reliable predictions of wall temperature and void fraction. Specifically, this study validates the appropriate simulation conditions for predicting local subcooled downward-facing boiling heat transfer by comparing the simulated results using different bubble dynamic parameter combinations with experimental observations. The validated conditions not only accurately predict heat transfer effects but also effectively capture bubble characteristics, including bubble thickness, velocity, and void fraction. Furthermore, the influence of turbulence models and interfacial heat transfer effects was analyzed. Overall, the findings indicate that under the proposed simulation conditions, CFD can reliably reproduce both heat transfer performance and bubble dynamics in the local subcooled downward-facing boiling phenomenon.

Processes doi: 10.3390/pr14111740

Authors: Daniel Velloso Cabral Roberto Braz da Silva Filho Tatianne Ferreira de Oliveira Claudio Fernandes Cardoso Alessandra Lopes de Oliveira Julio Cesar Colivet Briceno Flávio Alves da Silva

Coffee has a complex aroma, over 1000 volatile compounds, and high lipid content. However, it is prone to volatile loss and lipid oxidation during storage. This makes packaging critical for quality preservation. This study evaluated monomaterial and multimaterial packaging for roasted Coffea arabica. Moisture, pH, and color were monitored. Volatile compounds were analyzed (GC–MS). Phenolics were determined (Folin–Ciocalteu). Antioxidant activity (ABTS, DPPH, and FRAP) was integrated into a relative antioxidant capacity index. Oxidative stability was assessed via acid value, peroxide, p-anisidine, total oxidation, and fatty acid profile (GC–MS) in oil extracted by supercritical fluid. Shelf-life was estimated from peroxide and p-anisidine values using kinetic models with the Arrhenius equation and nonlinear regression (Levenberg–Marquardt). Multimaterial packaging showed greater stability at 50 °C. pH remained slightly variable. Color changes were more pronounced in monomaterial packaging. Notably, freshness-related volatiles, such as 2,3-butanedione and 3-methylbutanal, decreased, while deterioration markers increased, like 1-methylpyrrole-2-carboxaldehyde and ethylpyrazine. Phenolics and antioxidant activity also declined, especially in monomaterial packaging. Monomaterial packaging showed lower oxidative stability and shorter shelf-life (179 and 63 days) than multimaterial packaging (466 and 79 days). However, monomaterial packaging remains promising due to its lower material requirements, recyclability, and lower environmental impact.

Processes doi: 10.3390/pr14111739

Authors: Xuguang Bai Ran Yin Guorui Jing Jie Liu Yao Qu Xin Zhang Ruirui Zhao Feng Li Wen Zhang Ning Xiao Tingting Zhang Shuhang Ren

The impending wave of retired wind turbines has brought the issue of blade recycling to the forefront, presenting a major test for global sustainable resource management. Among the recycling methods, pyrolysis can be regarded as the most effective treatment approach, which can recycle the glass fibers that account for about 80% of the total weight of the blade. However, the pyrolytic char remaining on the fiber surface and the damage to the fiber structure caused by the excessively high pyrolysis temperature can both have a negative impact on fiber recycling. In this paper, a pyrolysis and in situ oxidation process with low treatment temperature is proposed for the recycling of glass fibers from the thermosetting epoxy resin–glass fiber composite material in the blades. Pyrolysis is performed at 450 °C, yielding a residual char content of 3.56%. Subsequently, in situ oxidation is conducted at the same temperature by switching the atmosphere to air, while the char content is reduced to below 0.01%, meeting the industrial recycling standard and achieving a glass fiber yield of 74%. Characterization reveals that the fiber structure and properties are well maintained. Additionally, through a series of characterization and density functional theory (DFT) calculations, the pyrolysis pathway from the resin repeating unit to various liquid phase products is supposed, and the corresponding pyrolysis mechanism is concluded. This paper provided a practical and feasible process scheme and theoretical basis for the efficient and clean resource recovery of retired wind turbine blades.

Processes doi: 10.3390/pr14111737

Authors: Jie Liu Yican Wang Huimin Yu

Lipopeptide biosurfactants and petroleum sulphonates (PSs) have complementary molecular structures that can achieve ultralow interfacial tension (IFT), which is considered the primary mechanism for enhanced oil recovery (EOR). In this study, the phase behavior of lipopeptide compounded with PS/crude oil/water was investigated, which revealed that lipopeptide addition led to the formation of Winsor III middle-phase microemulsion. The synergistic mechanism of ultralow IFT and microemulsion formation enables the lipopeptide-compounded system (LASP) to achieve superior oil displacement efficiency compared with the regular alkaline/surfactant/polymer (ASP) flooding system. Core flooding results proved that under the same conditions, the LASP system increased oil recovery by 10.58% relative to the ASP system. Furthermore, when the ASP system could no longer improve recovery, switching to the LASP system provided an additional 9.55% oil recovery rate. Moreover, the LASP system exhibited superior wettability, interfacial activity, and anti-adsorption properties. These findings highlight the potential of lipopeptide biosurfactants as high-performance, environmentally friendly alternatives to synthetic surfactants in EOR processes.

Processes doi: 10.3390/pr14111738

Authors: Yisong Ni Yu Jiang Yuan Zong Sixian Zheng

Poly(trimethylene ether) glycol (PO3G), a bio-based polyether polyol with excellent flexibility and superior hydrolytic stability, has emerged as a critical raw material for the preparation of high-performance polymer materials. This work optimized the sulfuric acid-catalyzed polymerization process and assessed the feasibility of using p-toluenesulfonic acid (PTSA) as an alternative catalyst. A parametric study was conducted to establish a reliable operating window for the sulfuric acid system. DFT calculations demonstrated that the driving force for chain growth decreases with increasing chain length, that recombination between chains of significantly different lengths is more favorable than between chains of equal length, and that the formation of disulfate esters is thermodynamically more favorable. Although PTSA required a higher catalyst loading, the resulting polymer had a markedly lower yellowness index. Prolonged reaction times lead to a molecular weight plateau, especially at high PTSA concentrations, while the yellowness index continues to increase after reaching the plateau. 1H NMR analysis indicated the formation of benzenesulfonate monoester intermediates during PTSA catalysis, suggesting a potentially milder pathway and possibly fewer side reactions compared to the sulfuric acid system. This paper provides theoretical and experimental foundations for the green, efficient synthesis of PO3G and the catalyst optimization for analogous bio-based polyether polyols.

Processes doi: 10.3390/pr14111736

Authors: Xin Xu Wuyang Yang Xinjian Wei Kai Zhang Weisheng Wang Xiangyang Zhang Haishan Li

Three-dimensional geological structural modelling provides the geometric framework for sub-surface exploration and development. However, conventional workflows, driven primarily by seismic interpretation, often lack explicit constraints from expert knowledge and are difficult to update when interpretations evolve. In particular, the conventional surface-based workflow follows a sequential pipeline—from seismic interpretation through manual intersection editing to surface generation and pillar gridding—in which geological knowledge is embedded only implicitly through operator-dependent parameter tuning, making knowledge transfer and model reproducibility difficult. This study proposes an intelligent modelling methodology guided by a geological structure knowledge graph. The method includes: (i) a three-tier knowledge architecture (TKA) that formalises domain knowledge in entity, relationship and inference layers using RDF/OWL; (ii) a knowledge-driven intersection line generation algorithm (KILGA) coupled with a hierarchical adaptive mesh refinement scheme based on a posteriori error estimation (HAMR-APEE) to integrate geological constraints and mitigate boundary aliasing; and (iii) a bidirectional linkage mechanism between the knowledge graph and 3D models to support incremental updates following knowledge revision. The approach is validated in three petroliferous basins in China (Ordos, Qaidam and Sichuan), representing micro-amplitude, thrust-nappe and deep complex structural styles. Compared with a conventional surface-based workflow, the proposed method reduces modelling RMSE from 15–20 m to 5–8 m, improves geological reasonableness from ~85% to >95%, and shortens modelling cycles from months to weeks. These results demonstrate that explicit integration of formalised geological knowledge into the modelling pipeline can substantially enhance both accuracy and efficiency across a range of structural settings.

Processes doi: 10.3390/pr14111735

Authors: Anastasia Rapeyko Antonio Eduardo Palomares Urbano Díaz Michael Renz

The increasing share of renewable energy, such as solar and wind energy, in the energy mix implies a demand for sustainable energy storage systems for the mitigation of the intermittency of these energy sources. One option, therefore, is stationary batteries based on abundant sodium, stored in hard carbon (HC) anodes. In this work, following the sustainable by design principle, HCs were synthesized from cotton-based textile waste using three different thermochemical routes: hydrothermal carbonization (HTC) followed by pyrolysis under nitrogen atmosphere (HC-250-N), HTC followed by pyrolysis under a water vapor stream (HC-250-W), and direct pyrolysis (HC-direct-N). The impact of the synthesis method on the physicochemical properties and electrochemical performance of the HCs was thoroughly investigated. X-ray diffraction, Raman spectroscopy, electron microscopy, and gas adsorption analyses revealed that the HTC pre-treatment significantly enhanced the carbon content, microporosity, and degree of structural graphitic order. HC-250-N exhibited the highest graphitic character and more uniform microstructure, while HC-250-W showed the largest specific surface area and broader micropore distribution. Electrochemical evaluation in sodium-ion half-cells indicated that HC-250-N delivered the most balanced performance, with a reversible capacity of 335 mAh g−1 and good cycling stability. These findings confirm the potential of textile waste-derived HCs as promising and sustainable anode materials for sodium-ion batteries and highlight the importance of tailoring synthesis parameters—such as HTC treatment and pyrolysis conditions—to optimize their structural and electrochemical properties.

Processes doi: 10.3390/pr14111734

Authors: Yufeng Shen Yu Song Jian Yi Wentong He Xuanlong Shan Ang Li Ying Bian Nan Jiang Shuyang Wang Yongbo Zhang

Oil shale in situ conversion provides an important pathway for developing medium- to deep-buried, low-grade, and thin oil shale resources. Among the available approaches, the in situ conversion technology triggered by the topochemical reaction method, hereafter referred to as the TSA method, induces local oxidation reactions of pyrolysis residuals, fixed carbon, and reactive organic matter through preheating and oxygen-containing gas injection. The released in-formation heat then supports continued kerogen cracking and reaction-front propagation. This review summarizes the TSA method from a process-oriented perspective, linking reaction mechanisms, engineering controls, geochemical process identification, pilot tests, economic–environmental constraints, and scale-up evaluation. Existing studies indicate that the TSA method has formed a technical chain involving reaction initiation, heat/reaction-front propagation, oil and gas recovery, and process monitoring. Pilot tests provide evidence for operational feasibility, but not yet for full commercial feasibility. Thermal simulation results show that oil and gas generation and expulsion become significant above ~350 °C, and that 375–425 °C can be used as an important reference window for temperature control rather than a fixed optimum for all oil shale reservoirs. Geochemical indicators can provide complementary constraints for identifying reaction progress, especially when calibrated with produced oil and gas. Further development should focus on fracture-network control, heat-transfer enhancement, oxygen-supply regulation, multi-well coordination, equipment reliability, economic evaluation, groundwater protection, and CO2 emission accounting. These issues are critical for advancing the TSA method toward larger-scale, low-carbon, and well-regulated application.

Processes doi: 10.3390/pr14111732

Authors: Congshi Li Zhengxun Lv Shouguo Song Ke Bian Jingxi Zhang Lei Kou

To improve the accuracy of cutter wear and service life prediction for disc cutters, an improved normal force model is established based on the traditional CSM model by considering the supporting force and friction acting on the disc cutter from the side crushing zones. By incorporating the micro-mechanism of abrasive wear, an analytical model for the radial wear of the disc cutter and a service life prediction model are derived. Meanwhile, a regression model for cutter wear is established based on field operational parameters and cutter wear data. The mechanistic model is validated using field data from a tunnel project in Guangdong, China, and the results show that the average prediction errors of wear and service life are 8.13% and 8.85%, respectively, which are significantly lower than those of the traditional CSM model. Further comparative analysis between the two types of models is conducted, and the results indicate that the regression model achieves average prediction errors of 7.57% and 7.86% for wear and service life, respectively, showing higher prediction accuracy than the mechanistic model. The results demonstrate that the mechanistic model is suitable for revealing the wear mechanism of the disc cutter, while the regression model is more applicable for engineering prediction, and the two approaches can be used in a complementary manner.

Processes doi: 10.3390/pr14111733

Authors: Rui Wang He Liu

The complex fracture networks, multiphase flow behavior, and nonlinear flow mechanisms induced by hydraulic fracturing in horizontal wells of shale oil reservoirs pose significant challenges to production evaluation. In this study, a semi-empirical productivity evaluation method for multiphase shale oil systems is developed by integrating production dynamics with flow mechanisms. Three-phase productivity equations for oil, gas, and water are established, explicitly incorporating the underlying flow mechanisms. A nonlinear flow index is introduced to characterize both the stress sensitivity of fractures and the threshold pressure gradient in the matrix. Key unknown parameters, including oil saturation, water cut, stimulated reservoir volume, and nonlinear coefficients, are determined through history matching of production data. The impacts of geological properties, fracturing parameters, operating conditions, and nonlinear flow parameters on oil–gas productivity are systematically investigated using the proposed multiphase semi-empirical model. The model is validated against production data from fractured horizontal wells in a field case, demonstrating its accuracy and applicability. Furthermore, the model enables reliable production forecasting based on the derived productivity relationships. The proposed approach provides a practical and efficient tool for rapid post-fracturing productivity evaluation in shale oil reservoirs.

Processes doi: 10.3390/pr14111731

Authors: Xiaohu Yang Yonghui Wu Kui Sun Liqiang Ma Jie Peng Shuyue He Shicheng Li Shiqi Chen

Liquid-phase mineralization of CO2 using coal fly ash (CFA) is an efficient approach to permanent CO2 sequestration. To address the low leaching efficiency of calcium ions (Ca2+) in carbon mineralization, this study systematically investigates the leaching performance and leaching mechanism of calcium ions from CFA by using a sequential alkaline-acid processing (i.e., alkaline activation followed by acid leaching). The effects of NaOH concentration, acid concentration, acid type (HCl/CH3COOH), reaction time, and grinding duration on leaching efficiency are studied. The reaction products are characterized by X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). A kinetic model is proposed to analyze the reaction dynamics and leaching mechanisms. The results show that the maximum Ca2+ leaching efficiency for untreated CFA is 43.7% after 40-min acid leaching with 7 mol/L HCl and 1:1.5 S/L ratio. The leaching efficiency can be enhanced to 72.1% after 50-min alkaline activation with 11 mol/L NaOH. Grinding the CFA can further increase the leaching performance of Ca2+. It is shown that the leaching efficiency can be enhanced to 58.75% and 82.3% after 90-min grinding, respectively, for cases without and with 50-min alkaline activation using 9 mol/L NaOH. It is also shown that a peak leaching efficiency of 86.51% can be obtained when 8 mol/L CH3COOH is used for the acid system. The mechanism for the enhancement of leaching efficiency is that both NaOH activation and mechanical grinding can break down the calcium and aluminum silicate vitreous matrix of CFA, facilitating calcium release. Ca2+ leaching performance exhibits two regimes. The leaching efficiency is significantly time-dependent in the first regime, and it remains almost constant in the second regime after the efficiency reaches a pseudo-maximum value. The contribution of this study is that a theoretical foundation is provided for enhancing the Ca2+ recovery from CFA, which makes it practical for large-scale CFA utilization and permanent CO2 sequestration in industry applications.

Processes doi: 10.3390/pr14111730

Authors: Juan José Lozada-Castro Jhon David Cueltan-Solarte Carlos Alberto Guerrero-Fajardo

Applying selective iconic flow cells, we studied the degradation of organic matter, using urea as a reference pattern to a concentration of 10% and domestic residual waters taken from a characteristic flow of water in the Colombian city of Pasto. The experiments were performed in two hours, and we carried out the analysis in different stages. To assess the chemical demand of oxygen (COD) and to measure the quantity of produced hydrogen by selective ionic flow cells (SIFCs), the monitoring system Mhydros was used. Furthermore, a photovoltaic cell of 100 watts was used as the energy resource for the organic matter oxidation. The results point out that the SIFCs do degrade the organic matter by 64.3% wt and produce hydrogen with an electrical efficiency of 104.7% in two hours.

Processes doi: 10.3390/pr14111729

Authors: Milica Stožinić Jovana Petrović Branislav Šojić Biljana Pajin Attila Gere Đurđica Ačkar Ivana Nikolić Ivana Lončarević

Over the past decade, changes in consumer dietary habits have driven an increasing demand for protein-enriched confectionery products. Consequently, research has increasingly focused on the utilization of alternative protein origins, including Acheta domesticus. This research paper aims to characterize Acheta domesticus protein powder (CP) in terms of its functional properties and chemical composition. In addition, the amino acid profile was determined using HPLC, while antioxidant capacity was evaluated by spectrophotometric methods (including the ABTS assay). Edibility was further assessed in proteins, both in their native form and after incorporation into cocoa cream products, using an in vitro digestion model. The results indicated that methionine was the most abundant essential amino acid in CP (17.71 mg/100 g protein), while glycine was the predominant non-essential amino acid (42.38 mg/100 g protein). CP also demonstrated high solubility (80.00%) and notable water- and oil-binding capacities (90.26% and 94.87%, respectively). However, its emulsifying properties were limited, as emulsifying stability was maintained for only 26 min. In contrast, digestibility results indicated strong protein hydrolysis in both native and cocoa cream samples enriched with CP in different concentrations (10, 12.5 and 15%), hereafter designated as CPC10, CPC12.5, and CPC15. The degree of hydrolysis was higher after the digestion process, with 39.11% for the control and 47.14%, 48.62% and 50.05% for the fortified samples—CPC10, CPC12.5 and CPC15, respectively. The ABTS assay further confirmed the increase in antioxidant activity after digestion. The ABTS values of the digested fortified samples ranged from 20.91% for CPC10 to 40.45% for CPC15, suggesting the release of bioactive peptides during gastrointestinal digestion. Overall, the findings highlight CP as a promising protein source for the fortification of cocoa cream products, which are naturally low in protein content.

Processes doi: 10.3390/pr14111727

Authors: Gang Hui Hai Wang

This editorial synthesizes the key findings from 17 original research articles featured in the Special Issue on “Intelligent and Integrated Approaches for Efficient Oil and Gas Development.” The collection demonstrates a paradigm shift from purely data-driven methods toward physics-informed, interpretable, and operationally deployable intelligent systems across the upstream lifecycle. Advances span intelligent drilling with real-time model predictive control frameworks achieving sub-20 ms execution times and bottomhole pressure fluctuations below 0.30 MPa; AI-assisted reservoir characterization using multiscale convolutional neural networks, seismic waveform-constrained inversion, and geology-informed transformers that improve sandstone thickness prediction (R2 = 0.895) and stratigraphic correlation (F1 = 0.886); production optimization through hybrid decomposition-ensemble models (R2 = 0.954) and improved XGBoost (R2 = 0.989); and enhanced oil recovery via self-assembled foam systems and polymer injector designs. Fundamental geochemical studies on the Qiongzhusi Formation shale and tight sandstone gas in the Ordos Basin provide critical geological constraints. The editorial identifies persistent challenges, including real-time performance versus physical fidelity, interpretability and uncertainty quantification, multi-scale integration, and generalizability across diverse geological settings. Future directions highlight reinforcement learning for autonomous operations, physics-informed digital twins, generative AI for subsurface scenario modelling, and integration with carbon capture, utilization, and storage. This Special Issue advances the convergence of petroleum engineering, artificial intelligence, and Earth sciences toward intelligent, secure, and sustainable hydrocarbon development.

Processes doi: 10.3390/pr14111726

Authors: Helong Fang Zelin Li Jingyu Li Ye Tao Yingying Wang

With the rising proportion of renewable energy in power systems, electricity markets are confronting escalating challenges driven by the accumulation of imbalance funds, especially in high renewable penetration sending-end grids with large-scale high voltage direct current (HVDC) transmission. Existing studies have not fully addressed the impact of renewable energy volatility and HVDC plan deviations on imbalance settlement, and lack an optimization framework that balances market fairness and system security constraints. This paper takes the electricity market of a northwestern province in China as the research object, first identifies the main sources of imbalance funds, and then develops a multi-objective settlement optimization model centered on minimizing imbalance funds, which integrates system power balance, nodal voltage limits, generation plan deviation, and HVDC transmission constraints. A responsibility attribution-based imbalance fund allocation mechanism is further proposed to improve market fairness. Empirical analysis based on actual market data shows that the optimized settlement mechanism reduces imbalance funds by an average of 28.9% under typical scenarios, and significantly improves market operational efficiency. This study provides a practical solution for the sustainable development of high renewable penetration electricity markets.

Processes doi: 10.3390/pr14111728

Authors: Yuan Pan Xuewei Liu Ping Guo Jianbing Li Liyong Yang Tao Zhao Quan Wang Yingxi Zhang Zheng Li

Multi-cluster perforation staged fracturing in horizontal wells has become an important means of completion stimulation for unconventional oil and gas reservoirs. However, the non-uniform propagation of multi-cluster hydraulic fractures remains one of the key challenges restricting efficient reservoir stimulation. In this study, based on the finite element method and considering factors such as frictional pressure drop along the wellbore for power-law fluid, perforation friction, and stress interference, a fracture propagation model with dynamic multi-stage flow distribution coupling formation, perforation, and wellbore flow was constructed. The effects of non-uniform perforation schemes, total number of perforations, and perforation non-uniformity coefficient on multi-cluster fracture propagation behavior were systematically investigated, and the characteristics of dynamic flow distribution were clarified. The results show that the order of fluid intake uniformity among different perforation schemes is as follows: spindle-shaped perforation, uniform perforation, and Tapered perforation. Reducing the number of perforations and decreasing the perforation non-uniformity coefficient can improve the uniformity of fracture propagation to a certain extent. The findings of this study can provide a theoretical basis and practical reference for efficient fracturing stimulation of shale oil in the Cangdong Sag.

Processes doi: 10.3390/pr14111725

Authors: Izabelle S. L. Batista Eduardo H. Wanderlind

The use of plant extracts in the preparation of catalysts has grown considerably in the last few years, motivated mainly by the search for overall catalytic processes that are more economically viable and sustainable. The diversity of species and specific parts of the plants that can be used for preparing the extracts, coupled with the several categories of catalysts that can be prepared, and the different chemical transformations that can be targeted for catalysis imply a huge field of possibilities. In this perspective, we present some recent advances in this field through the revision of a small selection of examples that, although connected, are quite different among them, highlighting the diversity and potential prospects of the subject. Lastly, we compiled some specific suggestions that can be of interest, particularly for beginners in this area, to render a more unified, straightforward presentation of the experimental data related to this subject.

Processes doi: 10.3390/pr14111724

Authors: Miloš Županjac Predrag Ikonić Eva Ivanišová Miroslava Kačániová Attila Gere Dubravka Škrobot Dragana Ubiparip Tamara Dapčević Hadnađev Milica Pojić Branislav Šojić

Fava bean (Vicia faba L.) is a nutritionally valuable and sustainable legume with strong potential for plant-based food applications. However, similar to other lipid-containing food systems, fava bean-based spreads are susceptible to lipid oxidation during storage, leading to quality deterioration and reduced shelf life. This study evaluated the effect of basil (Ocimum basilicum L.), winter savory (Satureja montana L.), and cumin (Cuminum cyminum L.) essential oils (EOs) (0.1 μL/g) on the physicochemical properties and oxidative stability of fava bean-based spreads during 90 days of storage at 4 °C. Four treatments were prepared: control spread without essential oil (B-CO), basil essential oil-enriched spread (B-BA), winter savory essential oil-enriched spread (B-WS), and cumin essential oil-enriched spread (B-CU). Water activity and pH remained stable in all samples throughout storage. Color changes were most pronounced in the control, while B-WS exhibited the highest color stability (ΔE = 1.81 vs. 6.07 in B-CO). Winter savory and cumin significantly reduced peroxide value and thiobarbituric acid reactive substance (TBARS) formation and improved oxidative stability (Rancimat: 9.11 and 9.10 h vs. 7.73 h in B-CO), whereas basil showed no protective effect. Cumin was characterized by the highest flavonoid and phenolic acid contents, while winter savory exhibited the highest total polyphenols. Sensory evaluation revealed that EOs significantly influenced consumer acceptance, particularly taste and aroma. Although the control sample achieved the highest overall scores, cumin-containing formulations provided the most favorable balance between oxidative stability and sensory quality, whereas winter savory negatively affected overall acceptability. Taken together, winter savory and cumin EOs effectively enhanced oxidative stability, highlighting their potential as natural antioxidants in the development of plant-based spreads.

Processes doi: 10.3390/pr14111723

Authors: Omar Ashraf Abdulazim Eman Y. Tohamy Dong-Fang Deng Saber A. El-Shafai

The potato chip processing (PCP) industry generates huge amounts of wastewater heavily polluted with organic matter and nutrients. The current treatment technology of PCP wastewater uses dissolved air flotation (DAF) and an activated sludge sequential batch reactor (SBR); both consume large amounts of chemicals and represent energy-intensive systems. This study explores the utilization of algae for the sustainable treatment of PCP wastewater, nutrient recovery, and algal biomass production. Conical flasks (1-L) and 6-L transparent plastic bottles were used as lab-scale algae photobioreactors (APBRs). Raw wastewater, an anaerobically pre-treated effluent and a DAF–SBR or shortly SBR effluent were used in the first, second, and third APBR. Three feed volumes from each source (150 mL, 300 mL, and 500 mL for first and second APBR and 400 mL, 600 mL, and 800 mL for third APBR) to a fixed volume of algal seed (200 mL) were tested to select the optimal feed volume and harvest time using a 1-L APBR. System performance and impact of water characteristics on quantity and quality of algal biomass were explored at pre-selected feed volume and harvest time in 6-L APBRs. All experiments were carried out in a growth chamber with continuous light (148.75 μmol.m−2.S−1). The results showed that 150 mL is the optimal feed volume for the first and second APBR at 10 days and 9 days growth cycles. An amount of 500 mL and 6 days were selected as the optimal feed volume and growth cycle for the third APBR. The average dry biomass yields at the pre-selected optimal conditions were 65.3 ± 11.4, 69.9 ± 12.0, and 100.6 ± 11.7 mg/L.d in the first, second, and third APBR, respectively. The first APBR achieved removals of 99.2 ± 0.4%, 98.7 ± 0.8%, 89.1 ± 4.3%, and 97.5 ± 1.4% for turbidity, COD, TKN, and TP, respectively, on average. Corresponding removal in the second APBR is 97.6 ± 2.6%, 91.6 ± 7.5%, 93.6 ± 4.5%, and 96.1 ± 1.4%, respectively, while the third APBR achieved 98.5%, 76.2%, and 97.0%, respectively. Additionally, the results of protein content and amino acids profiles indicate significant impacts of feed water quality on both parameters. The protein content was 30.64%, 32.53%, and 35.65% in the first, second, and third APBR, respectively. Similarly, the amino acids profile indicated a significant higher percentage of the amino acids in the third reactor compared with the first and second reactor.

Processes doi: 10.3390/pr14111721

Authors: Pamela Georgieva Yavor Ivanov Zlatina Chengolova Gjore Nakov Tzonka Godjevargova

The valorization of winery by-products is a sustainable strategy for receiving valuable bioactive compounds. The aim of this study was to obtain Syrah grape seed extract and investigate the stability of extract phenolic compounds and antioxidant capacity. Separated grape seeds from grape pomace were dried under two different conditions: 23 °C for 10 days and 40 °C for 24 h. Polyphenols were extracted from the dried seeds using 70% aqueous ethanol under magnetic stirring at 600 rpm for 3 h. The yield, color, nutrition value, and mineral contents of the extract were determined. The obtained extracts from the seeds dried at different temperatures were concentrated using a vacuum evaporator. The concentrate was subsequently divided into three forms: liquid, lyophilized, and dried at 40 °C. The individual phenolic components of the lyophilized grape seed extract were determined by HPLC. All extracts were stored at 4 °C and 23 °C for 10 months. The effect of the grape seed drying conditions, extract forms, storage temperature, and time on the total phenolic content, total flavonoids, procyanidins, and antioxidant capacity of the extracts was investigated. Changes in these parameters were evaluated at 0, 3, 6, and 10 months of storage. Degradation kinetics on the basis of antioxidant activity during extracts storage were calculated. Additionally, the individual phenolic composition of liquid and lyophilized Syrah grape seed extracts stored for 10 months was determined by HPLC. The degradation degree of the individual compounds in the extracts was calculated.

Processes doi: 10.3390/pr14111720

Authors: Yangyang Guo Yingfeng Sun Jian Chen Hao Xu Yikai Zhang

With the gradual depletion of shallow coal resources and the continuous increase in mining intensity in coal-producing regions, coal mining is progressively deepening [...]

Processes doi: 10.3390/pr14111722

Authors: Min Du Boyu Liu Tao Zhang Shuqi He Yongchun Zhang

Coke deposition on the inner wall of helical coils in organic heat carrier (OHC) furnaces imposes additional thermal resistance, which impairs heat transfer and may trigger tube over-temperature failure. However, the quantitative coupling among the coking degree, flow conditions, and wall temperature response in helical coils remains insufficiently characterized. To address this gap, a three-dimensional steady-state conjugate heat-transfer model that resolves the additional thermal resistance of the coke layer is established using computational fluid dynamics (CFD). A dimensionless coking degree ω, defined as the ratio of coke layer thickness to inner tube radius, is introduced to parameterize the deposition state. Parametric simulations are performed at ω = 0–20%, with oil inlet velocities of 1–3 m/s. As ω increases from 0% to 20%, the maximum outer wall temperature rises by 66.1% (344 °C to 572 °C), whereas the maximum inner wall temperature decreases by 6.5%. The inner–outer wall temperature difference increases by over two orders of magnitude (1.61 °C to 251 °C), and the heat absorption of thermal oil declines by 53.4%. Raising the inlet velocity lowers the outer-wall temperature under clean-wall conditions, whereas this cooling effect is markedly diminished under severe coking. These findings provide a quantitative basis for the early-stage diagnosis of coking and safety evaluation of OHC furnaces.

Processes doi: 10.3390/pr14111719

Authors: Tong Wu Junjie Huang Qihao Qian Quanhou Li

Accurate reservoir-fluid identification and water saturation prediction are essential for remaining-oil evaluation and water-flooding adjustment in heterogeneous oilfields. However, in the Youshashan Oilfield, southwestern Qaidam Basin, China, thin interbeds, strong reservoir heterogeneity, complex oil–water transitions, and inter-well logging-response differences make conventional single-task interpretation difficult. To address these problems, this study proposes a joint prediction method based on the Youshashan Fluid Prediction Network (YSF-Net) for six-class reservoir-fluid identification and continuous water saturation (Sw) prediction. A total of 200 wells were used and strictly divided by well into 140 training wells, 30 validation wells, and 30 independent test wells to avoid data leakage. Conventional logs were first processed through depth matching, outlier correction, robust standardization, and missing-value masking. Then, sliding-window logging sequences, regional stratigraphic embeddings, and reservoir-prior parameters, including shale volume, porosity, and permeability, were jointly input into the YSF-Net. The model uses a shared feature encoder with classification and regression branches to simultaneously identify oil layers, oil–water layers, water layers, and weakly, moderately, and strongly water-flooded layers, while predicting continuous Sw. A modified Simandoux-based physical consistency constraint was further introduced during training to improve the geological rationality of Sw prediction. Experimental results show that YSF-Net outperforms the CNN, BiLSTM, CNN-BiLSTM, and Transformer. It achieves an Accuracy of 0.926, Macro-F1 of 0.913, Macro-AUC of 0.968, Sw RMSE of 0.061, Sw MAE of 0.047, and Sw R2 of 0.947. In direct cross-well testing without fine-tuning, YSF-Net obtains a Cross-well Accuracy of 0.918, Cross-well Macro-F1 of 0.904, and Cross-well Sw RMSE of 0.064. Ablation, transition-boundary, and typical well-interval analyses further demonstrate that regional constraints, reservoir-prior inputs, multi-task learning, and physical consistency improve class-boundary discrimination and Sw prediction reliability. The proposed method provides an accurate, consistent, and practical workflow for intelligent reservoir-fluid interpretation in heterogeneous reservoirs.

Processes doi: 10.3390/pr14111718

Authors: Yu Liu Jiapeng Lu Qimeng Liu Jingzhong Zhu Chongyan Liu

Shallow coal resources are being gradually depleted, which has led to an increase in mining depth. However, the safe extraction of deep coal seams is increasingly threatened by limestone water hazards. When vertical hydraulic channels such as karst collapse columns (KCCs) develop in limestone strata, high-pressure water may flow into the mine, potentially causing substantial casualties and property losses. In this study, the 1613A stope of the Zhangji coal mine was investigated through comprehensive detection, grouting treatment, and prevention effect evaluation. A numerical model was established to simulate the dynamic changes in groundwater levels within the limestone aquifers throughout the process. The results reveal that a KCC is developed beneath the C33 stratum, exhibiting an oval shape with a length of 53 m and a width of 35 m in plan view. A combination of surface and underground methods, including exploration, treatment, verification, and reinforcement, has sealed the hydraulic pathway connected to the Ordovician limestone, thereby eliminating the threat of floor water inrush. These findings are of significant value for the application and dissemination of advanced regional control technologies for water hazards in coal mines.

Processes doi: 10.3390/pr14111717

Authors: Cristian Mugurel Iorga Puiu Lucian Georgescu Constantin Ungureanu Mihaela Marilena Stancu

The use of sewage sludge for the bioremediation of hydrocarbon-contaminated soils remains insufficiently documented, particularly regarding microbial dynamics and material behavior during treatment. Although petroleum-hydrocarbon contamination severely disrupts soil functions, sewage sludge—through its high organic matter content, active bacterial communities, and fine mineral fraction—offers potential for the sustainable remediation of such soils. Three soil–sludge mixtures (P1:N1, P2:N1, P1:N2) were monitored to assess hydrocarbon degradation, bacterial community dynamics, and material behavior. Hydrocarbon-degrading and hydrocarbon-tolerant bacteria remained active, while sludge-derived Enterobacteriaceae declined below detection limits. Enrichment cultures of the sludge yielded three hydrocarbon-degrading strains (Providencia alcalifaciens IBBN1, Klebsiella pneumoniae IBBN2, Acinetobacter tandoii IBBN3), highlighting the metabolic potential of the active microbial communities. A moderate increase in surfactant concentrations reflected both residual anionic surfactants and biosurfactant production by these consortia, facilitating hydrocarbon mobilization. Total petroleum hydrocarbons (TPH) decreased by 45–60% (IR), and GC-FID analysis showed preferential degradation of C10–C40 fractions. Heavy-metal concentrations remained stable, indicating no geochemical changes or inhibitory effects on bacterial activity. Overall, the results confirm the potential of sewage sludge as a sustainable amendment that accelerates hydrocarbon biodegradation and supports integrated soil-restoration strategies.

Processes doi: 10.3390/pr14111716

Authors: Emrah Kuzu Soner Top Sait Kursunoglu Mahmut Altiner

Hydrometallurgical leaching processes contain complex and nonlinear parameter interactions that are difficult to capture with conventional empirical models. In this study, a multiple hybrid machine learning approach was developed to predict manganese (Mn) and iron (Fe) dissolution efficiency in leaching systems and performed using sulfuric acid (H2SO4), hydrochloric acid (HCl), and nitric acid (HNO3). A large-format dataset consisting of 204 independent leaching experiments was generated in which acid type, acid concentration (0.5–5 M), temperature (25–90 °C), solid/liquid ratio (100–200 g/L), leaching time (1–4 h), and eight different reducing agent types were systematically varied. XGBoost, LightGBM, CatBoost, and Random Forest algorithms were individually trained and subsequently combined with a Soft Voting Ensemble architecture. Hyperparameters were optimized using the RandomizedSearchCV method with 3-fold cross-validation. The XGBoost model achieved the highest prediction accuracy for Mn dissolution (R2 = 0.8993, RMSE = 8.06%), while CatBoost demonstrated the best performance in Fe dissolution (R2 = 0.8415, RMSE = 4.43%). SHAP analysis suggested that the dosage and type of reducing agents are the most influential predictive features for Mn dissolution, while acid molarity and temperature were identified as the dominant predictors for Fe leaching. Friedman test confirmed that performance differences among both Mn and Fe models were statistically significant (Mn: χ2 = 32.76, p < 0.001; Fe: χ2 = 25.96, p < 0.001). The developed models contribute significantly to hydrometallurgical process optimization by predicting the nonlinear effects of leaching parameters on metal dissolution with high accuracy. This study presents a comprehensive and interpretable machine learning framework supported by an extensive experimental dataset, a substantial portion of which has not been previously utilized or comparatively analyzed within a unified multi-acid framework, enabling systematic modeling of selective Mn–Fe dissolution across multiple acid systems and reducing agents.

Processes doi: 10.3390/pr14111715

Authors: Zhongqing Sang Maosheng Sun Po Li Dibin Huang

To address the issues of start-up over-temperature and sharp reduction in creep life caused by the lack of droplet evaporation latent heat cooling effect when adapting micro turbojet engines (MTEs) to gaseous fuels (GFs), this study optimized the start-up control strategy based on the heat accumulation effect (HAE). By establishing a 160 kgf-class MTE GF experimental platform, the nonlinear coupling mechanism between the “supply-and-burn” characteristic of GFs and the lag of rotor aero-thermodynamic response was deeply analyzed. The study found that traditional linear fuel supply strategies ignore the closed-loop energy balance under the small volume effect of the combustor, which easily causes the exhaust gas temperature (EGT) to remain above the safety threshold for a prolonged period. Unlike conventional continuous ramping strategies, this study proposes a novel open-loop multi-stage thermal relief start-up strategy. By introducing speed dwell windows in the early ignition and mid-acceleration stages, dynamic thermal relaxation intervals were constructed to achieve a “deep washout” of the accumulated thermal load. Experimental results indicate that although the optimized strategy slightly increases the instantaneous peak temperature due to the adjustment of the acceleration slope, it effectively cuts off the over-temperature time. Specifically, the over-temperature duration is reduced from 17.2 s to 11.4 s (a 33.7% reduction), and the over-temperature severity index decreases from 756.76 °C·s to 451.70 °C·s (a 40.3% reduction). This strategy successfully achieves the smooth start-up of the GF MTE, providing an efficient and reliable start-up control paradigm for the transition of micro power systems to low-carbon/zero-carbon fuels.

Processes doi: 10.3390/pr14111709

Authors: Bao Cao Chunwei Ling Zhenyu Tai Liangchen Zhao Jiyuan You

The geometric characteristics of these fractures have a substantial influence on the mechanical and energy properties of heterogeneous rocks. This study calibrated the experimental results using the finite-discrete element method (FDEM). An orthogonal design was employed to investigate the effects of the homogeneity coefficient, fracture angle, fracture length, and fracture aperture on the mechanical and energy characteristics of fractured sandstone. The main factors influencing the mechanical properties and energy characteristics of rocks were explored through multi-factor correlation analysis. The effects of fracture geometric features and heterogeneity on the mechanical properties and energy characteristics of rocks were analyzed by single-factor analysis. A regression model between peak stress and fracture geometric features was established. The results show the following: The homogeneity coefficient and fracture length have a significant impact on the elastic modulus of fractured sandstone. The fracture angle and fracture length have a significant influence on the peak strain, elastic strain energy and total energy of fractured sandstone. The fracture angle, fracture length and homogeneity coefficient have a significant effect on the peak stress of fractured sandstone. The elastic modulus and peak stress show a logarithmic relationship with the homogeneity coefficient, while the elastic strain energy and total energy have a logarithmic relationship with the crack length. The peak strain and peak stress have a quadratic polynomial relationship with the crack angle, and the elastic strain energy and total energy also have a quadratic polynomial relationship with the crack angle. The elastic modulus, peak strain, and peak stress have a logarithmic relationship with the crack length. The predicted values of peak stress and numerical calculation errors of fractured rocks mainly range from 0.07% to 7.76%, with an average error of 2.58%. Both the peak stress prediction values and the numerical calculation results show a “U”-shaped change trend, first decreasing and then increasing with the increase in the fracture angle. This study investigates the influence of fracture geometric characteristics on the mechanical and energy characteristics of heterogeneous rocks, which is of great significance for the stability control of fractured rock masses and the optimization of underground engineering parameters. The core challenge for future research lies in revealing the intrinsic connection among fracture geometric features, rock mass heterogeneity, and multi-field coupling effects to meet the complex engineering demands of deep mining, thereby serving the safe production and disaster prevention of deep mines.

Processes doi: 10.3390/pr14111714

Authors: Shen Guan Zhiqiang Hu Gengchen Li Xuyue Chen Minghe Zhang Yamei Hao

To address the large deviation in annular trapped pressure prediction during testing and production stages of deepwater high-temperature and high-pressure wells, conventional models neglect the elastic uplift effect of the wellhead. This study overcomes the limitations of the plane strain model and establishes a three-dimensional thermos–hydro–mechanical coupled annular pressure prediction model based on the longitudinal stiffness constraint of the subsea wellhead. The deepwater wellbore–formation system is treated as a composite elastic structure. A generalized plane strain assumption is introduced to define the elastic boundary conditions and longitudinal segmentation characteristics of the wellhead. Based on generalized Hooke’s law, the three-dimensional stress–strain constitutive equation of casing is modified. A displacement model incorporating axial–radial coupling is derived, and an equivalent longitudinal stiffness coefficient of the wellhead is introduced. A coupled axial force equilibrium equation and a three-dimensional annular volume compatibility equation are established. Considering multi-annulus coupling, a volume compatibility matrix equation is formulated, and a successive approximation iterative algorithm with a relaxation factor is developed. Using a deepwater high-temperature, high-pressure gas well in the South China Sea as a case study, the effects of wellhead stiffness, free section length, and annular temperature rise on annular pressure are investigated via a single-variable method and compared with traditional rigid models. Results show that the subsea wellhead exhibits elastic uplift behavior. Its longitudinal stiffness has a reverse S-shaped nonlinear influence on annular pressure. Increasing the free section length significantly reduces annular pressure. The proposed model predicts values 17–21% lower than traditional rigid models, providing a more realistic representation of annular pressure evolution. The findings offer theoretical support and engineering guidance for deepwater well integrity design and annular pressure risk management.

Processes doi: 10.3390/pr14111710

Authors: Chen Wang Long He Yuan Zong

Liquid distributors are critical internals in packed columns, whose distribution uniformity directly governs the column’s hydrodynamic performance, mass transfer efficiency, and operational stability. To address the poor liquid distribution uniformity of trough distributors under high liquid loads, this study proposes a novel trough distributor integrated with a resistance–guidance synergistic composite unit. Combining numerical simulations and experimental validation, the core synergistic mechanism of the unit was systematically investigated. The horizontal baffle serves as a secondary throttling point, which converts axial kinetic energy into static pressure energy to supplement the driving force for transverse energy redistribution and physically suppresses the generation and development of large-scale vortices. Meanwhile, vertical guide vanes guide liquid flow, constrain the expansion of harmful secondary flows, and construct a controllable transverse pressure gradient. The resistance–guidance unit collaboratively realizes two-stage energy conversion and redistribution, reconstructs the liquid momentum transfer path, and restores the static pressure gradient-dominated transverse energy transport mechanism. This study clarifies the intrinsic mechanism of resistance–diversion synergy for liquid distribution control, laying a theoretical foundation for the structural optimization of trough liquid distributors under high-liquid-load conditions.

Processes doi: 10.3390/pr14111712

Authors: Višnja Vasilj Nikolina Kajić Jozo Ištuk Leona Puljić Jana Šic Žlabur Mia Dujmović Krešimir Mastanjević

The study aimed to evaluate the influence of growing location and drying method on the physicochemical properties, bioactive compound composition, and antioxidant capacity of wild Rosa canina L. fruits collected from four Herzegovinian locations. Significant differences were observed among locations and drying methods for all analysed physico-chemical parameters. Fresh fruits exhibited high dry matter content (average 54.6%). The highest ascorbic acid content was recorded in fresh fruits from location L1 (112.20 mg/100 g fw), whereas drying reduced its concentration approximately 3.7-fold. Total phenolic content ranged from 1205.45 mg GAE/100 g fw in fresh fruits from location 1 to markedly lower values after drying (approximately 50% reduction). β-carotene content varied from 1.01 to 20.12 mg/100 g fw, with the highest level detected in fresh fruits from location 4, while lycopene ranged from 3.33 to 59.28 mg/100 g fw, with fresh fruits from location 1 showing exceptionally high values. Fresh fruits exhibited the highest antioxidant capacity (ABTS assay), while dried samples retained considerable activity, with significant location-dependent interactions between growing site and drying method. Results confirm that pedo-climatic conditions significantly shape the bioactive profile of rosehip fruits and highlight Herzegovinian rosehip as a valuable functional material for food, nutraceutical, and pharmaceutical industries.

Processes doi: 10.3390/pr14111713

Authors: Claudia Victoria Deysi Amado-Piña Rubi Romero Sandra Luz Martínez-Vargas Alejandro Regalado-Méndez Patricio J. Espinoza-Montero Reyna Natividad

Metformin (MET) is a widely prescribed pharmaceutical compound used for the management of glucose levels and body weight. However, it is only partially metabolized in the human body, and a significant fraction is excreted unchanged, leading to its frequent detection in aquatic environments. Consequently, the removal of MET from wastewater has become a matter of increasing concern due to its potential impact on aquatic ecosystems. Furthermore, as a nitrogen-containing compound, MET has been extensively employed as a model pollutant to evaluate the performance of physical and chemical treatment technologies for pharmaceutical contaminants. This review aims to critically assess and summarize the efficiency and key limitations of various processes applied for MET removal. The reviewed approaches include physical–chemical treatments such as adsorption; biological treatments (activated sludge, biofiltration and phytoremediation), which rely on microbial metabolic activities or plant uptake to degrade or sequester metformin; and advanced oxidation processes (AOPs), such as ozonation, photolysis, photocatalysis, Fenton, and photo-Fenton systems. The efficiency of MET removal and mineralization is strongly dependent on the treatment method employed. Among the evaluated processes, the photo-Fenton reaction emerges as one of the most promising technologies, achieving high removal efficiencies under both ultraviolet (UV) and visible (Vis) irradiation.

Processes doi: 10.3390/pr14111711

Authors: Tianjing An Weihao Xu Rundong Hu Dan Gao Chao Cheng Yu Gao Jiaxi Yang

Integrated energy systems (IES) are widely recognized as a key pathway toward carbon neutrality, enabling the coupling and coordinated optimization of electricity, heat, gas, and cooling. This review provides a structured, technology-oriented overview of IES based on a unified five-subsystem framework (production, conversion, transmission, storage, and consumption). It systematically covers: (1) renewable energy utilization—solar, wind, and geothermal—supported by a global spatial distribution map and representative top-performing commercial products; (2) energy cascade utilization, where combined heat and power/combined cooling, heating and power (CHP/CCHP) raises overall efficiency from approximately 35–40% to 70–90%; (3) multi-form energy storage—electrical, electrochemical, chemical, thermal, and mechanical—distinguishing short-term balancing (e.g., lithium-ion (Li-ion), flywheels, supercapacitors, with 85–95% round-trip efficiency) from long-duration and seasonal applications (e.g., pumped hydro, hydrogen/power-to-gas (P2G), redox flow batteries); and (4) forecasting, collaborative optimization, and the bidirectional integration of IES with smart grids and grid modernization. A strategic strengths, weaknesses, opportunities, and threats–Political, Economic, Sociological, Technological, Legal, and Environmental (SWOT–PESTLE) analysis is further presented to position IES within the global energy transition. The review highlights that IES and grid innovation are mutually enabling, and that realizing the full carbon-neutrality potential of IES requires coordinated progress in standardization, digitalization, long-duration storage, and cross-sector policy alignment.

Processes doi: 10.3390/pr14111708

Authors: Mingxing Wang Jingchen Zhang Peng Xu Linjie Wang Jingchun Zhang Shixin Qiu Min Xiang Jiawen Li Zhanjie Li

Rough-walled fractures in conglomerate reservoirs promote near-wellbore proppant deposition, nonuniform flow, and insufficient distal support, making proppant-schedule screening difficult using small-scale smooth-slot tests alone. This study develops a benchmark-constrained and cost-aware hierarchical screening workflow by integrating a 20 m rough-wall physical experiment, transient Fluent simulations, and archived short-time EDEM sensitivity records. The benchmark experiment used a 20 m × 4.5 m × 10 mm artificial rough-wall fracture and ten operating conditions involving pumping rate, fluid viscosity, proppant size, and sand concentration. In the Fluent model, wall roughness was treated as a regularized roughness representation, and the carrier fluids were modeled using Newtonian constant viscosities measured from laboratory calibration. The experimental effective propped area ranged from 25.5% to 65.1%. Within single-factor comparison subsets, medium viscosity improved support continuity, pumping-rate gains became limited near 0.20 m3/min, particle size affected the balance between distal coverage and bed stability, and 300 kg/m3 sand concentration caused blockage. Image-segmentation-based comparison showed that Fluent captured the main wedge-shaped deposition morphology and screening-level geometric trends. The archived EDEM records indicated that grid-resolution refinement and mixed particle-size representation substantially increased computational cost. A Case 10 mesh-sensitivity check further confirmed that mesh refinement did not alter the first-order deposition morphology. The proposed workflow uses Fluent for whole-domain rapid screening and reserves EDEM/CFD-DEM for targeted short-time sensitivity checks.

Processes doi: 10.3390/pr14111707

Authors: Elisabeta Atyim Laura Atyim Marius Mioc Alexandra Mioc Codruța Șoica Dan Radu Gheorghe Roxana Negrea-Ghiulai Nicoleta Anamaria Paşcalău

The anti-apoptotic Bcl-2 protein family, frequently upregulated in a wide range of cancers, contributes to tumor persistence and therapeutic resistance, making these proteins attractive targets for structure-based inhibitor development. Betulinic acid-derived hybrids represent promising scaffolds for apoptosis-oriented anticancer drug discovery due to their reported antiproliferative and pro-apoptotic properties. In this study, a virtual library of 152 betulinic acid-derived hybrids was screened against Bcl-2 and Bcl-XL. This molecular docking study using AutoDock Vina identified BA–Celastrol and BA–Proanthocyanidin B2 as top-ranked ligands, with docking scores ranging from −13.00 to −8.7 kcal/mol. Both compounds were further analyzed by 100 ns molecular dynamics simulation runs, which revealed system-dependent ligand behavior rather than uniform preservation of the initial docked pose across all complexes. BA–Celastrol showed a more compact internal ligand conformation in the ligand property and RMSF analyses, whereas BA–Proanthocyanidin B2 showed greater intramolecular flexibility and conformational adaptability. Ligand displacement relative to the protein differed between targets, with BA–Proanthocyanidin B2 showing a more retained profile in the Bcl-XL model and BA–Celastrol showing more moderate positional behavior in the Bcl-2 model. MM-GBSA calculations resulted in free energy values ranging from −4.95 to −31.82 kcal/mol, indicating protein-dependent energetic differences across the investigated systems. Based on docking performance, molecular dynamics stability, and energetic data, both hybrids were ranked as computational candidates for further exploration against Bcl-2 family targets. The present findings, although confined to computational analysis, underscore the need for prioritizing betulinic acid-based hybrids for subsequent experimental evaluation.

Processes doi: 10.3390/pr14111706

Authors: Daoyi Zhu

Geo-energy systems, including oil, gas, and geothermal ones, are accelerating toward a synergistic development stage characterized by high efficiency, low energy consumption, and low carbon emissions [...]

Processes doi: 10.3390/pr14111705

Authors: Mengzhen Yuan Juan Tang Hui Shang Ziyuan Wang Yunping Hu

As a promising alternative fuel, oilfield tail gas can reduce environmental pollution while achieving secondary utilization. Studying the cylinder-to-cylinder working uniformity is crucial for evaluating the feasibility of such oilfield tail gas as a source of engine fuel. This study establishes a single-bank six-cylinder model based on GT-POWER using a 12V190 V-type natural gas generator engine with a symmetrical structure. The effects of air–fuel ratio (λ), fuel injection timing (FIT), and ignition advance angle (IAA) on cylinder-to-cylinder working uniformity are analyzed through in-cylinder pressure fluctuation rate, using the univariate method. Base values: λ = 1.0, FIT = 270° crank angle before top dead center (° CA BTDC), IAA = 10° CA BTDC. Tested values: λ = 1.0, 1.3, 1.6, 2.2; FIT = 260, 270, 280° CA BTDC; and IAA = 10, 8, 6° CA BTDC. Results show that the minimum fluctuation rate occurs at λ = 1.0, FIT = 260° CA BTDC, IAA = 10° CA BTDC. Deviating from this optimal condition—by increasing λ, retarding FIT, or advancing IAA—increases fluctuation rate, indicating poorer uniformity. Thus, optimal cylinder-to-cylinder working uniformity is achieved at these specific conditions. This research provides a theoretical basis and technical reference for the efficient secondary utilization of oilfield tail gas in power-generation engines.

Processes doi: 10.3390/pr14111704

Authors: Lihao Zhou Liangbin Dou Chengyun Ma Shanshan Quan Fengtao Qu Wenxuan Kou Chenbo Gu Chi Zhao Baiqi Mao Kai Zhao Yanfang Gao

Yanfang Gao was not included as an author in the original publication [...]

Processes doi: 10.3390/pr14111703

Authors: Hongjuan Teng Yuejiao Xing Yue San Li Zheng Zhongjiang Wang Bailiang Li

Freezing effectively extends the shelf life of food and maintains product quality by inhibiting microorganisms, enzyme activity, and chemical reactions. However, issues such as ice crystal formation, protein denaturation, lipid oxidation, and the low-temperature adaptability of psychrophilic microorganisms during the freezing process can directly affect the final quality of frozen foods. Among these, the size and distribution of ice crystals are key factors determining the extent of tissue damage. Therefore, this review aims to identify innovative and optimized freezing and frozen storage strategies. In order to save energy and improve product quality, various new technologies have emerged in recent years, such as ultrasonic-assisted freezing, high-pressure freezing, and magnetic-field-assisted freezing. This study systematically discusses the principles, applications, and impact mechanisms of these technologies on frozen foods. Furthermore, this study proposes the future development trends of frozen foods, filling the gap in the current food industry where there is a lack of systematic discussion and evaluation of frozen foods. It provides technical support and research directions for continuous development and innovation in the field of frozen foods.

Processes doi: 10.3390/pr14111702

Authors: Buling Tian Xiaojun Li Haoran Chen Jian Li Yang Wang

Coalbed methane (CBM) is an important unconventional natural gas resource, and coal seam gas content is a key parameter for CBM resource evaluation and favorable-zone prediction. Taking the Jiulongchuan exploration area in Gansu Province as the study area, this study integrated drilling, well-logging, and measured gas content data to establish a multivariate regression model for coal seam gas content prediction. On this basis, three-dimensional geological modeling and variogram analysis were applied to characterize the spatial distribution of gas content in the main mineable coal seams (Nos. 5, 6, and 8). The results indicate that the regression model constructed using acoustic transit time, natural gamma-ray values, density logging parameters, and burial depth shows generally reasonable predictive capability for coal seam gas content. Cross-validation results suggest that the predicted gas contents are generally consistent with measured values. Spatial modeling results show that gas content in Seam No. 8 is generally higher than that in Seams No. 5 and No. 6, and gas content tends to increase with burial depth and coal seam thickness. In addition, relatively high gas contents are commonly observed along synclinal zones, whereas lower values occur near anticlinal areas. The integrated application of well-log interpretation and three-dimensional geological modeling provides a reasonable characterization of the spatial variation in coal seam gas content in the study area. The results may provide useful references for CBM resource evaluation and favorable-zone prediction in the Jiulongchuan exploration area.

Processes doi: 10.3390/pr14111701

Authors: Sapura Satayeva Askar Bakushev Svetlana Yermukhanova Altynai Kupeshova Nurgul Satybayeva Aliya Urazova Firuza Akhmetova

This study reports the development of a hierarchically porous material based on natural diatomite, thermally treated diatomite (450 °C), and an activated carbon-modified diatomite composite for saline groundwater treatment in West Kazakhstan, addressing the need for efficient desalination solutions under real environmental conditions. The material was synthesized via sequential thermal activation at 450 °C followed by incorporation of activated carbon, with bentonite used as a binder to improve mechanical stability. Comprehensive physicochemical characterization (SEM, XRD, XRF, BET, DTA, and FTIR) confirmed significant structural and compositional transformations, including silica enrichment, removal of impurities, and the development of a well-defined hierarchical porous network. The specific surface area increased from 8 to 10 m2/g for natural diatomite to 35–40 m2/g for thermally treated diatomite and further to 55–60 m2/g for the activated carbon-modified diatomite composite, accompanied by enhanced pore volume and mesoporosity. Performance evaluation using real groundwater samples demonstrated that thermally treated diatomite (450 °C) improved removal efficiency by approximately 19%, while the activated carbon-modified diatomite composite achieved 35–37% removal of chloride, sulfate, and total dissolved solids under multi-ion competitive conditions. The enhanced adsorption performance is attributed to the synergistic effect of increased surface area, improved pore accessibility, and additional active sites introduced by activated carbon. The adsorption process is governed by ion bridging mediated by multivalent cations, pore filling within the hierarchical pore structure, and surface complexation on silanol and metal–hydroxyl functional groups. Leaching tests confirmed the structural stability of the composite and indicated no significant release of environmentally relevant elements under aqueous conditions. Compared with natural diatomite, the thermally treated and activated carbon-modified materials demonstrate improved adsorption efficiency and stable performance under realistic groundwater conditions. These results highlight their applicability for decentralized water treatment systems in regions affected by saline groundwater contamination.

Processes doi: 10.3390/pr14111700

Authors: Jin Zhang Jun Fan

The thermodynamic effect of SiO2 on the composition of the weld metal in submerged arc welding is analyzed by employing the basicity index model, the slag–metal model, and a multi-zone thermodynamic framework. A CaF2-SiO2 binary flux system is employed to isolate the intrinsic effect of SiO2. The results show that the basicity index model captures the overall decrease in weld metal O content with increasing flux basicity index but fails to resolve variations in the high-basicity region. The slag–metal equilibrium model provides a thermodynamic description of interfacial reactions yet remains limited to the weld pool zone. In contrast, the multi-zone model incorporates reactions in the droplet and weld pool zones, revealing pronounced O enrichment in the droplet due to flux decomposition and arc–plasma interactions, followed by redistribution under gas–slag–metal equilibrium. By accounting for droplet-stage evaporation and cross-zone interactions, the multi-zone model improves the predictive accuracy of Si and Mn contents and explicitly captures their cross-zone transfer behavior compared with conventional prediction approaches.

Processes doi: 10.3390/pr14111699

Authors: Diego E. Peralta-Guevara Fredy Taipe-Pardo Yasmine Diaz-Barrera Jhoel Flores-Álvarez Sofía Pastor-Mina

The buildup of non-biodegradable plastic waste and poor management of agro-industrial by-products have caused a major environmental crisis. The present research addresses the development of novel materials supporting the circular bioeconomy. This study aimed to develop and characterize bio-composite films derived from native Oxalis tuberosa starch and keratin microparticles (KMPs) extracted from cattle horn waste. The experimental methodology employed a 23 factorial design and involved the characterization of the films included the evaluation of physical and optical properties and the identification of functional groups via spectroscopy, mechanical tests, and thermogravimetric analysis (TGA). The results revealed significant interactions (p ≤ 0.05). Higher processing temperatures were the main reason for the drop in water activity (aw) and moisture content (MC) levels. Concurrently, the incorporation of KMPs reduced water solubility, increased opacity, and enhanced thermal stability. FTIR analysis confirmed the existence of intermolecular interactions between the hydroxyl and amide functional groups. In conclusion, bio-composites composed based on Oxalis tuberosa starch and keratin microparticles represent a sustainable alternative to mitigate the use of conventional plastics in the industry.