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Processes, Volume 13, Issue 2 (February 2025) – 154 articles

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27 pages, 865 KiB  
Article
Towards a Dynamic Optimisation of Comminution Circuit Under Geological Uncertainties
by Alain M. Kabemba, Kalenda Mutombo and Kristian E. Waters
Processes 2025, 13(2), 443; https://doi.org/10.3390/pr13020443 (registering DOI) - 6 Feb 2025
Abstract
Geometallurgical programmes are crucial for designing mineral processing plants that maximise comminution throughput. However, the variability of complex ore bodies, such as platinum group element (PGE) deposits, poses challenges in developing these programmes into profitable mine-to-mill production. This paper investigates the geological characteristics [...] Read more.
Geometallurgical programmes are crucial for designing mineral processing plants that maximise comminution throughput. However, the variability of complex ore bodies, such as platinum group element (PGE) deposits, poses challenges in developing these programmes into profitable mine-to-mill production. This paper investigates the geological characteristics of different lithologies hosting the complex PGE orebody located in the Northern Limb of the Bushveld igneous complex in South Africa and assessed their impact on metallurgical efficiency in comminution circuits. Regression machine learning techniques were employed to analyse the ore mineralogical dataset from two lithologies (feldspathic pyroxenite and pegmatoidal feldspathic pyroxenite) and predict the Bond Work Index (BWI), a key comminution parameter for calculating processing plant throughput. The results indicated that BWI is strongly influenced by Chlorite, silicates, iron oxides, and the relative density of the PGE deposit. Using both simulated and laboratory-measured throughput values, a particle swarm optimisation (PSO) algorithm was applied to maximise the plant’s comminution throughput through tactical blending of low-grade and high-grade ore stockpiles. The PSO algorithm was shown to be an effective tool for stockpile management and tactical mine-to-mill operation in response to feed mineralogical variability. This first-time innovative approach addresses complex geological uncertainties and lays the groundwork for future geometallurgical studies. Potential areas for further research include incorporating additional lithologies for tactical ore stockpile blending and optimising parameters critical for ore mineral flotation. Full article
(This article belongs to the Section Manufacturing Processes and Systems)
16 pages, 498 KiB  
Article
Enzymatic Synthesis of Bioactive Structured DHA Phospholipids via Stable Immobilized Phospholipase-Catalyzed Esterification in a Solvent-Free Medium
by Ernestina Garcia-Quinto, Jose M. Guisan and Gloria Fernandez-Lorente
Processes 2025, 13(2), 442; https://doi.org/10.3390/pr13020442 - 6 Feb 2025
Abstract
The enzymatic esterification of docosahexaenoic acid (DHA) with glycerophosphocholine (GPC) was investigated to produce bioactive structured DHA phospholipids with DHA esterified at the sn-2 position, which may contribute to the prevention of neurodegenerative diseases such as Alzheimer’s. This reaction is complex due to [...] Read more.
The enzymatic esterification of docosahexaenoic acid (DHA) with glycerophosphocholine (GPC) was investigated to produce bioactive structured DHA phospholipids with DHA esterified at the sn-2 position, which may contribute to the prevention of neurodegenerative diseases such as Alzheimer’s. This reaction is complex due to the low solubility of GPC in anhydrous organic media and the limited stability of enzymes under such conditions. The immobilized phospholipase Quara® LowP (QlowP-C18) proved to be the most effective catalyst, achieving a 58% yield of di-substituted DHA phospholipids (Di-DHA-PC) in just 48 h under optimal conditions (solvent-free media at 60 °C) with 95% purity. Advanced immobilization and post-immobilization techniques significantly improved the stability of QlowP-C18, increasing its longevity threefold and enabling reuse for up to five reaction cycles at 40 °C. The total production reached 120.4 mg of highly pure DHA-di-substituted phospholipid. These findings highlight the effectiveness of stable immobilized enzymes in solvent-free systems and underscore their potential for the efficient and sustainable production of highly pure Di-DHA-PC, which could be used as a functional or nutraceutical ingredient for the prevention of neurodegenerative diseases. Full article
(This article belongs to the Section Food Process Engineering)
9 pages, 5922 KiB  
Communication
Forming Rate Dependence of Novel Austenitising Bending Process for a High-Strength Quenched Micro-Alloyed Steel: Experiments and Simulation
by Yao Lu, Jun Wang, Zhou Li, Fei Lin, Di Pan, Fanghui Jia, Jingtao Han and Zhengyi Jiang
Processes 2025, 13(2), 441; https://doi.org/10.3390/pr13020441 - 6 Feb 2025
Abstract
This austenitising bending investigation was carried out in a vacuum environment with the forming rates of 1, 10, and 100 mm/min under a certain bending temperature of 900 °C by a thermomechanical simulator. The enhanced strength at the accelerated forming rate and on [...] Read more.
This austenitising bending investigation was carried out in a vacuum environment with the forming rates of 1, 10, and 100 mm/min under a certain bending temperature of 900 °C by a thermomechanical simulator. The enhanced strength at the accelerated forming rate and on the compression/tension zones throughout the thickness of the bent plates was discussed in detail in terms of dislocation pile-up, smaller prior austenite grain size, dynamic recrystallisation, smaller martensite packet, and stress-neutral layer. Since the simulation results were validated to match the experimental trend, this investigation could be applied as a valuable reference to simulate the practical manufacturing process of railway fasteners. Full article
(This article belongs to the Special Issue Processing, Manufacturing and Properties of Metal and Alloys)
24 pages, 4753 KiB  
Article
Optimization and Application of Bio-Enzyme-Enhanced Gel-Breaking Technology in Fracturing Fluids for Tight Sandstone Gas in the Linxing Block, Ordos Basin
by Jiachen Hu, Gaosheng Wang, Weida Yao, Yu Li, Meiyang Jing, Tian Lan, Zhongxu Xie and Anxun Du
Processes 2025, 13(2), 440; https://doi.org/10.3390/pr13020440 - 6 Feb 2025
Abstract
The main tight sandstone gas reservoirs in the Linxing block of the Ordos Basin exhibit a temperature range of 35–60 °C. Under these low-temperature conditions, conventional oxidative gum breakers used in fracturing operations react sluggishly, fail to break the gum completely, and can [...] Read more.
The main tight sandstone gas reservoirs in the Linxing block of the Ordos Basin exhibit a temperature range of 35–60 °C. Under these low-temperature conditions, conventional oxidative gum breakers used in fracturing operations react sluggishly, fail to break the gum completely, and can cause significant reservoir damage. In order to achieve complete breakage of the fracturing fluid and reduce the damage to the fracture and reservoir, active bio-enzyme-enhanced breakers have been incorporated into fracturing fluid formulations, so as to achieve rapid breakage, re-discharge at low temperature, and reduce the contact time between the fracturing fluid and the formation, which is critical for enhancing production efficiency. Based on the preliminary success of bio-enzyme-enhanced fracturing technology, this paper carries out an optimization study of bio-enzyme-enhanced fracturing technology for the low-temperature reservoir in the Ordos Linxing block. The study simulates the temperature recovery of the injected fluids under different reservoir temperatures during the fracturing process, aiming to further optimize the concentration of the bio-enzyme-enhanced fracture breakers in the fracturing phases, and to achieve optimized fracturing technology which is more in line with the temperature environment of the fluids. This can further optimize the concentration of the bio-enzyme breaker added at each fracturing stage, and achieve enhanced breaking in a stepwise manner that is more in line with the fluid temperature environment, thus improving the efficiency and production capacity for subsequent production. The optimized fracturing fluid system, incorporating the tailored concentration of the bio-enzyme breaker, was applied to 54 wells in this block, resulting in about a two-times improvement in production compared to conventional non-optimized methods, with many wells achieving high output. These results demonstrate the strong applicability of the optimized breaker procedure in this geological context. Additionally, this study investigated an optimization model for the well shut-in time during winter operations involving low-temperature fracturing fluids in low-temperature reservoirs, providing a valuable design basis for future production planning. Full article
(This article belongs to the Special Issue Modeling, Control, and Optimization of Drilling Techniques)
16 pages, 2689 KiB  
Article
Flow and Corrosion Analysis of CO2 Injection Wells: A Case Study of the Changqing Oilfield CCUS Project
by Wei Lv, Tongyao Liang, Cheng Lu, Mingxing Li, Pei Zhou, Xing Yu, Bin Wang and Haizhu Wang
Processes 2025, 13(2), 439; https://doi.org/10.3390/pr13020439 - 6 Feb 2025
Abstract
In carbon dioxide capture, utilization and storage (CCUS) technology, CO2 flooding and storage is currently the most effective geological storage method and the flow law of the gas injection wellbore is the key to achieving safe and efficient CO2 injection. The [...] Read more.
In carbon dioxide capture, utilization and storage (CCUS) technology, CO2 flooding and storage is currently the most effective geological storage method and the flow law of the gas injection wellbore is the key to achieving safe and efficient CO2 injection. The existing wellbore flow model lacks research on the corrosion law. To this end, this paper established a gas injection wellbore flow-heat transfer-corrosion coupling model based on the actual situation of Huang 3 District of the CCUS Demonstration Base of Changqing Oilfield. The field measured data verification showed that the relative average error of the model in predicting pressure and temperature was less than 7.5% and the R2 of the predicted value and the measured value was greater than 0.99. The model was used for sensitivity analysis to evaluate the effects of different gas injection temperatures (15–55 °C), pressures (15–55 MPa), displacements (10–500 t/d) and CO2 contents (50–100%) on wellbore temperature, pressure and corrosion rate, and the wellbore flow law under different gas injection conditions was clarified. The results show that the wellbore temperature, pressure and corrosion rate are significantly affected by gas injection parameters. The wellbore temperature increases with the increase of gas injection temperature and decreases with the increase of gas injection displacement. The wellbore pressure is positively correlated with the gas injection pressure and CO2 content and the gas injection temperature and displacement have little effect on the pressure. The corrosion rate increases with the increase of gas injection temperature and displacement and decreases with the increase of gas injection pressure. In the wellbore, it shows a trend of first increasing and then decreasing with depth. The wellbore corrosion rate is affected by many factors. Reasonable adjustment of gas injection parameters (lowering temperature, increasing pressure, controlling displacement and CO2 content) can effectively slow down the wellbore corrosion loss. The research results can provide a theoretical basis for the optimization of gas injection system. Full article
15 pages, 4098 KiB  
Article
Effect of Collagen Peptide and Polysaccharide Combination on Astringency Elimination, Appearance, and Syneresis in Persimmon Paste
by Yoko Tsurunaga
Processes 2025, 13(2), 438; https://doi.org/10.3390/pr13020438 - 6 Feb 2025
Abstract
Astringency in persimmon fruit is often eliminated by treatment with gaseous carbon dioxide, dry ice, or alcohol. However, these methods are time-consuming and labor-intensive, and astringency may recur after heat treatment. In this study, a method for easily reducing astringency was investigated by [...] Read more.
Astringency in persimmon fruit is often eliminated by treatment with gaseous carbon dioxide, dry ice, or alcohol. However, these methods are time-consuming and labor-intensive, and astringency may recur after heat treatment. In this study, a method for easily reducing astringency was investigated by taking advantage of the benefits of combining proteins and polysaccharides. In the first experiment, the protein materials with strong astringency-reducing effects were screened from among 15 protein-rich foods using astringent persimmon juice (APJ), and collagen peptides were found to be highly effective. However, syneresis was observed when 1% collagen peptide powder was added to the astringent persimmon paste (AP). Therefore, in the second experiment, 0.5% collagen peptides (protein) were applied to reduce heating-induced astringency and reversion and 0.5% polysaccharides (guar, and xanthan gums) to maintain color and suppress syneresis. The results demonstrate that the combination of collagen peptide and polysaccharides is optimal for removing astringency in persimmon, inhibiting its recurrence by heating, and maintaining product quality. The results of this study may reduce the labor required for the astringency removal process, broaden the uses of AP, and facilitate the effective utilization of discarded astringent persimmons that do not meet the standards. Full article
(This article belongs to the Special Issue High-Value-Added Utilization of Food and Food By-Products)
27 pages, 2655 KiB  
Article
Risk Analysis of Hydrogen Leakage at Hydrogen Producing and Refuelling Integrated Station
by Jiao Qu, Ting Zhou, Huali Zhao, Jun Deng, Zhenmin Luo, Fangming Cheng, Rong Wang, Yuhan Chen and Chimin Shu
Processes 2025, 13(2), 437; https://doi.org/10.3390/pr13020437 - 6 Feb 2025
Abstract
Hydrogen energy is considered the most promising clean energy in the 21st century, so hydrogen refuelling stations (HRSs) are crucial facilities for storage and supply. HRSs might experience hydrogen leakage (HL) incidents during their operation. Hydrogen-producing and refuelling integrated stations (HPRISs) could make [...] Read more.
Hydrogen energy is considered the most promising clean energy in the 21st century, so hydrogen refuelling stations (HRSs) are crucial facilities for storage and supply. HRSs might experience hydrogen leakage (HL) incidents during their operation. Hydrogen-producing and refuelling integrated stations (HPRISs) could make thermal risks even more prominent than those of HRSs. Considering HL as the target in the HPRIS, through the method of fault tree analysis (FTA) and analytic hierarchy process (AHP), the importance degree and probability importance were appraised to obtain indicators for the weight of accident level. In addition, the influence of HL from storage tanks under ambient wind conditions was analysed using the specific model. Based upon risk analysis of FTA, AHP, and ALOHA, preventive measures were obtained. Through an evaluation of importance degree and probability importance, it was concluded that misoperation, material ageing, inadequate maintenance, and improper design were four dominant factors contributing to accidents. Furthermore, four crucial factors contributing to accidents were identified by the analysis of the weight of the HL event with AHP: heat, misoperation, inadequate maintenance, and valve failure. Combining the causal analysis of FTA with the expert weights from AHP enables the identification of additional crucial factors in risk. The extent of the hazard increased with wind speed, and yet wind direction did not distinctly affect the extent of the risk. However, this did affect the direction in which the risk spreads. It is extremely vital to rationally plan upwind and downwind buildings or structures, equipment, and facilities. The available findings of the research could provide theoretical guidance for the applications and promotion of hydrogen energy in China, as well as for the proactive safety and feasible emergency management of HPRISs. Full article
(This article belongs to the Special Issue Risk Assessment and System Safety in the Process Industry)
21 pages, 1180 KiB  
Article
Industrial Part Faults Prediction for Nonlinearity and Implied Temporal Sequences
by Shuyu Zhang, Mengyi Zhang, Cuimei Bo and Cunsong Wang
Processes 2025, 13(2), 436; https://doi.org/10.3390/pr13020436 - 6 Feb 2025
Abstract
The ability to preemptively identify potential failures in industrial parts is crucial for minimizing downtime, reducing maintenance costs and ensuring system reliability and safety. However, challenges such as data nonlinearity, temporal dependencies, and imbalanced datasets complicate accurate fault prediction. In this study, we [...] Read more.
The ability to preemptively identify potential failures in industrial parts is crucial for minimizing downtime, reducing maintenance costs and ensuring system reliability and safety. However, challenges such as data nonlinearity, temporal dependencies, and imbalanced datasets complicate accurate fault prediction. In this study, we propose a novel combined approach that integrates the Logistic Model Tree Forest (LMT) with Stacked Long Short-Term Memory (LSTM) networks, addressing these challenges effectively. This hybrid method leverages the decision-making capability of the LMT and the temporal sequence learning ability of Stacked LSTM to improve fault prediction accuracy. Additionally, to tackle the issues posed by imbalanced datasets and noise, we employ the ENN-SMOTE (Edited Nearest Neighbors-Synthetic Minority Over-sampling Technique), a technique for data preprocessing, which enhances data balance and quality. Experimental results show that our approach significantly outperforms traditional methods, achieving a fault prediction accuracy of up to 98.2%. This improvement not only demonstrates the effectiveness of the combined model but also highlights its potential for real-world industrial applications, where high accuracy and reliability are paramount. Full article
(This article belongs to the Section Manufacturing Processes and Systems)
40 pages, 2111 KiB  
Article
Sustainable Domestic Sewage Reclamation: Insights from Small Villages and Towns in Eastern China
by Ying Kang, Fangfang Ye, Zucheng Wu, Qiqiao Wang, Yulan Yuan and Dingxun Ye
Processes 2025, 13(2), 435; https://doi.org/10.3390/pr13020435 - 6 Feb 2025
Abstract
Domestic sewage pollution poses significant risks to human health and the ecological environment but sewage water is gradually recognized as a renewable water resource worldwide. To enhance water resource utilization and facilitate reclamation from domestic sewage, substantial global efforts have focused on developing [...] Read more.
Domestic sewage pollution poses significant risks to human health and the ecological environment but sewage water is gradually recognized as a renewable water resource worldwide. To enhance water resource utilization and facilitate reclamation from domestic sewage, substantial global efforts have focused on developing systematic management strategies and advanced technologies for treatment and resource recovery. This study examines and presents the case of domestic sewage reclamation and water reuse in the rural Hangjiahu region, situated on the southern bank of Taihu Lake in Northern Zhejiang Province, Eastern China. It provides a comprehensive overview of state-of-the-art technologies implemented in the region. In rural areas, sewage treatment is decentralized and involves two primary streams: one where urine is separately disinfected and sterilized, with feces processed into agricultural fertilizer; and another where greywater undergoes bio-composting and wetland treatment to produce recycled water. Additionally, natural rainwater is collected and stored in ponds, enhancing the region’s water resources. The results demonstrate that the integration of domestic sewage reclamation and rainwater storage has effectively mitigated the risks of flooding during rainy seasons and water shortages during droughts. Remarkably, no severe floods or droughts have occurred in the region since 1991, contrasting with historical records from 1909 to 1954, when such events were frequent. This study underscores the potential for replicating these approaches in other regions facing similar challenges. Full article
(This article belongs to the Section Sustainable Processes)
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24 pages, 3185 KiB  
Article
Molecular Dynamics Simulation of the Thermal Treatment of the Ara h 6 Peanut Protein
by Andrea Smith and Vijaya Raghavan
Processes 2025, 13(2), 434; https://doi.org/10.3390/pr13020434 - 6 Feb 2025
Abstract
The Ara h 6 protein is an important allergen found in peanuts (Arachis hypogaea). Ara h 6 represents a significant risk to human health, given its potential to trigger IgE-mediated anaphylaxis. Seeing as peanuts are often heat-processed prior to consumption, understanding [...] Read more.
The Ara h 6 protein is an important allergen found in peanuts (Arachis hypogaea). Ara h 6 represents a significant risk to human health, given its potential to trigger IgE-mediated anaphylaxis. Seeing as peanuts are often heat-processed prior to consumption, understanding the effect heat application has on the Ara h 6 protein’s structure and function is vital. Therefore, the purpose of this study was to explore, through the application of long-timescale 200 ns GROMACS molecular dynamics simulations, the structural changes that occur in the Ara h 6 allergen during thermal processing at 300 K, 350 K, 400 K and 450 K. Larger fluctuations in the Ara h 6 allergen’s secondary structure, RMSD and RMSF were identified at higher processing temperatures. However, observed decreases in Rg and SASA as processing temperature rose from 300 K to 400 K suggested that these observed fluctuations in the structure may be due to a compaction of the protein’s structure. Overall, the Ara h 6 allergen exhibited high thermostability. Full article
16 pages, 3624 KiB  
Article
Study on Applicability of Ball-and-Stick Model in Reservoir Pore-Throat Network Simulation
by Jinyou Dai, Yangyang Shi, Xizhen Lei, Xiaofeng Zhou, Zhiyang Pan, Xiaoshu Shen and Sha Pi
Processes 2025, 13(2), 433; https://doi.org/10.3390/pr13020433 - 6 Feb 2025
Abstract
At present, the ball-and-stick model is widely used to simulate the reservoir pore-throat network. However, due to the large span of reservoir pore-throats, there is still a lack of effective verification on whether the ball-stick model is fully applicable. The configuration analysis of [...] Read more.
At present, the ball-and-stick model is widely used to simulate the reservoir pore-throat network. However, due to the large span of reservoir pore-throats, there is still a lack of effective verification on whether the ball-stick model is fully applicable. The configuration analysis of a constant velocity mercury injection curve is carried out by using configuration theory and the hierarchical analysis method. The applicability of the ball-and-stick model in a reservoir pore-throat network simulation is discussed by interpreting the reservoir pore-throat structure information behind the configuration. The results show that there are two configuration regions, A and B, in the constant velocity mercury injection curve. In configuration region A, the mercury saturation of pores, the pore channel and the throats increase monotonically with the increase in mercury inlet pressure, indicating that pore channels and throats coexist in this configuration region, the pore-throat ratio is greater than one, and the ball-and-stick model is applicable. In the B configuration region, mercury saturation in pores and throats increases monotonically with the increase of mercury inlet pressure, while mercury saturation in the pore channel remains unchanged, indicating that this configuration region is basically throat with a porethroat ratio of one. The ball-and-stick model is no longer applicable, and the capillary model is more suitable. The ball-and-stick model combined with the capillary model can simulate the full-scale pore throat network of the reservoir. This study provides a method to calibrate the application zone of ball-stick model and capillary model by using constant velocity mercury injection curve configuration, which has important guiding significance for the simulation of the reservoir pore-throat network and the study of the seepage law. Full article
(This article belongs to the Section Advanced Digital and Other Processes)
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16 pages, 4980 KiB  
Article
A Novel Case of Cooling and Heating in Rectangular Lid-Driven Cavities: Interplay of Richardson Numbers in Streamlines and Isotherms
by Edgar Alexandro Gonzalez-Zamudio, Miguel Angel Olivares-Robles and Andres Alfonso Andrade-Vallejo
Processes 2025, 13(2), 432; https://doi.org/10.3390/pr13020432 - 6 Feb 2025
Abstract
The thermal and dynamic behavior of SiO2 nanofluid was studied in a rectangular lid-driven cavity using the finite difference method. A non-adiabatic lid and a hot section at the bottom wall were considered in different heating and cooling cases. Three novel study [...] Read more.
The thermal and dynamic behavior of SiO2 nanofluid was studied in a rectangular lid-driven cavity using the finite difference method. A non-adiabatic lid and a hot section at the bottom wall were considered in different heating and cooling cases. Three novel study cases were studied: a standard temperature at Th (heat conduction through the left-side walls), a high hot temperature, 2Th (heat conduction through the left-side walls), and a 2Tc high cold temperature (heat conduction through right-side walls). The Richardson number was varied between 10 and 100, and the lid direction. With a Richardson number of 10, the streamlines in the different cases tended to the formation of a central vortex with small vortices on the side walls, and the isotherms tended to a central one near the lower wall’s heated section and the homogenized temperature in the center of the cavity. At a Richardson number of 100, the streamlines produced a division in the cavity through a central vortex due to the heating of the bottom wall; this affected the isotherms, generating a prominent one in the center of the cavity and others near it. The generating decreased in the temperature near the bottom and top walls but increased in the middle of the cavity. The standard temperature case tended to behave similarly to the high cold temperature case but presented different temperatures, while the high hot temperature case generally maintained a slightly different behavior. These effects were more noticeable with the lid direction opposite X. Full article
(This article belongs to the Special Issue Applications of Nanofluids and Nano-PCMs in Heat Transfer)
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1 pages, 112 KiB  
Retraction
RETRACTED: Wang et al. Characterizing the Hydraulic Fracture Propagation Behavior in Deep Fractured Formations Based on DDM and FVM. Processes 2024, 12, 2469
by Bin Wang, Jingfeng Dong, Peiyao Zhou, Hui Kong, Kaixin Liu, Kebao Ding and Heng Zheng
Processes 2025, 13(2), 431; https://doi.org/10.3390/pr13020431 - 6 Feb 2025
Viewed by 50
Abstract
The journal retracts the article titled “Characterizing the Hydraulic Fracture Propagation Behavior in Deep Fractured Formations Based on DDM and FVM” [...] Full article
15 pages, 935 KiB  
Review
Cloud Point Extraction as an Environmentally Friendly Technique for Sample Preparation
by Bartosz Sznek, Olga Kupczyk and Andrzej Czyrski
Processes 2025, 13(2), 430; https://doi.org/10.3390/pr13020430 - 6 Feb 2025
Viewed by 77
Abstract
Cloud point extraction is a sample preparation technique that involves using surfactants that are not harmful to the environment. It is based on micelle formation in which the extracted compound is encapsulated in the hydrophobic core of the micelles, which are the extracting [...] Read more.
Cloud point extraction is a sample preparation technique that involves using surfactants that are not harmful to the environment. It is based on micelle formation in which the extracted compound is encapsulated in the hydrophobic core of the micelles, which are the extracting agent. The most commonly used surfactants are nonionic. The others are anionic, cationic, or zwitterionic. The effectiveness of cloud point extraction might be enhanced by the addition of neutral salts, the application of proper pH, as well as acidic conditions and temperature. This sample preparation technique may be applied to extract analytes from the following matrices, such as biological and environmental samples. Cloud point extraction may be combined with various analytical techniques and detectors such as HPLC-UV, HPLC-MS, HPLC-FLD, inductively coupled plasma–optical emission spectrometry, gas chromatography, and flame atomic absorption spectrometry. When it is combined with electrothermal atomic absorption spectrometry, the limit of quantitation is low—even of the order of ng/L. The recovery of the analyte may reach the value of 100%. Full article
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17 pages, 3863 KiB  
Article
Adsorption Pore Volume Distribution Heterogeneity of Middle and High Rank Coal Reservoirs and Determination of Its Influencing Factors
by Kai Wang, Fangkai Quan, Shizhao Zhang, Yubo Zhao, He Shi, Tingting Yin and Zhenyuan Qin
Processes 2025, 13(2), 429; https://doi.org/10.3390/pr13020429 - 6 Feb 2025
Viewed by 95
Abstract
Heterogeneity of adsorption pore volume distribution affects desorption and diffusion processes of coal reservoirs. In this paper, N2 and CO2 adsorption and desorption experiment tests were used to study the pore structure of middle and high rank coal reservoirs in the [...] Read more.
Heterogeneity of adsorption pore volume distribution affects desorption and diffusion processes of coal reservoirs. In this paper, N2 and CO2 adsorption and desorption experiment tests were used to study the pore structure of middle and high rank coal reservoirs in the study area. The fractal theory of volume and surface area is used to achieve a full-scale fractal study of adsorption pores (pore diameter is less than 100 nm) in the study area. Firstly, adaptability and control factors of volume fractals and surface area fractals within the same aperture scale range are studied. Secondly, fractal characteristics of micro-pores and meso-pores are studied. Thirdly, fractal characteristics within different aperture scales and the influencing factors of fractal characteristics within different scale ranges are studied. The results are as follows. With the increase in coal rank, pore volume and specific surface area of pores less than 0.8 nm increase, and dominant pore size changes from 0.55~0.8 nm (middle coal rank) to 0.5~0.7 nm (high coal rank). As coal rank increases, TPV and average pore diameter (APD) decrease under the BJH model, while SSA changes are not significant under the BET model. Moreover, as the pore diameter decreases, the correlation between the integral dimension of pore volume and degree of coal metamorphism decreases. This result can provide a theoretical basis for the precise characterization of the target coal seam pore and fracture structure and support the optimization of favorable areas for coalbed methane. Full article
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22 pages, 37689 KiB  
Article
Numerical Simulation of Flame Propagation in a 1 kN GCH4/GO2 Pintle Injector Rocket Engine
by Alexandru Mereu and Dragos Isvoranu
Processes 2025, 13(2), 428; https://doi.org/10.3390/pr13020428 - 6 Feb 2025
Viewed by 137
Abstract
Over the last few years, the appeal for using methane as green fuel for rocket engines has been on an increasing trend due to the more facile storage capability, reduced handling complexity and cost-effectiveness when compared to hydrogen. The present paper presents an [...] Read more.
Over the last few years, the appeal for using methane as green fuel for rocket engines has been on an increasing trend due to the more facile storage capability, reduced handling complexity and cost-effectiveness when compared to hydrogen. The present paper presents an attempt to simulate the ignition and propagation of the flame for a 1 kN gaseous methane–oxygen rocket engine using a pintle-type injector. By using advanced numerical simulations, the Eddy Dissipation Concept (EDC) combined with the Partially Stirred Reactor (PaSR) model and the Shielded Detached Eddy Simulation (SDES) were utilized in the complex transient ignition process. The results provide important information regarding the flame propagation and stability, pollutant formation and temperature distribution during the engine start-up, highlighting the uneven mixing regions and thermal load on the injector. This information could further be used for the pintle injector’s geometry optimization by addressing critical design challenges without employing the need for iterative prototyping during the early stages of development. Full article
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16 pages, 805 KiB  
Article
Production and Physicochemical and Microbiological Evaluation of Orange-Flesh Sweet Potato Flatbread Infused with Spinach as a Healthy Food Option
by Colleen Castillo, Vidya de Gannes, Gaius Eudoxie, Wendy-Ann P. Isaac and Sivakumar Karuppusamy
Processes 2025, 13(2), 427; https://doi.org/10.3390/pr13020427 - 5 Feb 2025
Viewed by 240
Abstract
Consumers’ preferences for healthier food products are increasing worldwide. Flatbread, a highly versatile product traditionally formulated with wheat flour (WF), offers significant potential for innovation and value addition through biofortification. Biofortification of flatbread was assessed with orange-flesh sweet potato (Ipomoea batatas L.) [...] Read more.
Consumers’ preferences for healthier food products are increasing worldwide. Flatbread, a highly versatile product traditionally formulated with wheat flour (WF), offers significant potential for innovation and value addition through biofortification. Biofortification of flatbread was assessed with orange-flesh sweet potato (Ipomoea batatas L.) flour (OFSP) infused with spinach (Amaranthus dubius). The purpose of this experiment was to ascertain the impact of adding local OFSP flour and spinach on the physicochemical, sensory, and microbial aspects of sweet potato-spinach infused WF flatbread. Six different flatbread formulations were created using OFSP flour, WF, and spinach. The study utilized a randomised 3 × 2 factorial design, with each treatment reproduced four times, totalling 24 treatments. Sensory evaluation for OFSP flour-spinach flatbreads received appreciable scores. OFSP flour flatbreads exhibited acceptable levels of protein, ash, fat, and moisture. The study provided formulations for value-added flatbread with the efficient inclusion of local agricultural resources OFSP and spinach to produce healthier food product offerings that were microbiologically safe. Full article
(This article belongs to the Special Issue Circular Economy and Efficient Use of Resources (Volume II))
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13 pages, 1465 KiB  
Article
Pre-Stack Nonlinear Direct Exact Inversion of Fracture Parameters in Deep Shale Reservoirs
by Meng Wang, Liang Yu, Tianchao Guo, Xiuyan Song, Xiaoxin Zhang and Yurun Rui
Processes 2025, 13(2), 426; https://doi.org/10.3390/pr13020426 - 5 Feb 2025
Viewed by 211
Abstract
A conventional linear pre-stack inversion method under the conventional stationary convolution model is limited by the assumptions of weak formation contrast change and small angle incidence and fails to take into account the amplitude attenuation of seismic wave propagation. Meanwhile, the resolution and [...] Read more.
A conventional linear pre-stack inversion method under the conventional stationary convolution model is limited by the assumptions of weak formation contrast change and small angle incidence and fails to take into account the amplitude attenuation of seismic wave propagation. Meanwhile, the resolution and precision of oil and gas evaluation and fracture characterization of shale reservoirs under complex geological conditions are low because the compaction and non-connectivity characteristics of deep shale reservoirs are not fully considered. Therefore, porous rock pores are divided into connected pores and disconnected pores. Combined with the effect of compaction on dry rock skeleton, a petrophysical model considering the compaction and pore dysconnectivity of deep shale reservoir is developed. The quantitative relationship between transverse isotropy with a vertical axis of symmetry (VTI) stiffness matrix, rock physical properties, and fracture parameters is established in this model. It provides a more accurate scheme for the original physical modeling of deep shale. This relationship is incorporated into the exact VTI reflection coefficient equation, and a nonstationary convolution operator is derived by using the attenuation theory of seismic wave propagation. A nonstationary pre-stack nonlinear direct inversion method of fracture parameters of shale reservoirs with horizontal fractures is proposed, which Improves the resolution and accuracy of shale reservoir gas bearing and fracture characteristics prediction. It provides a new way to accurately characterize the fracture development and oil-bearing property of shale reservoirs. A model test and field data test verify the effectiveness of this method. Full article
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17 pages, 6593 KiB  
Article
The Study of Interlayer Identification Based on Well Logging Curve Units
by Shoumin Chen, Junjian Li, Yan Lei, Zhi Fan, Ma Suo, Qin Wang, Xiaoqi Liu and Yongchao Xue
Processes 2025, 13(2), 425; https://doi.org/10.3390/pr13020425 - 5 Feb 2025
Viewed by 241
Abstract
The distribution of interlayers in reservoirs has a significant impact on the flow of reservoir fluids. Accurate identification of interlayer distribution is crucial for analyzing oil–water migration patterns and formulating optimal development strategies. Current research on interlayers mainly focuses on qualitative analysis, particularly [...] Read more.
The distribution of interlayers in reservoirs has a significant impact on the flow of reservoir fluids. Accurate identification of interlayer distribution is crucial for analyzing oil–water migration patterns and formulating optimal development strategies. Current research on interlayers mainly focuses on qualitative analysis, particularly regarding sedimentary environments and petrophysical characteristics. However, research on the quantitative analysis of interlayers is relatively scarce, and most identification methods rely on manual interpretation, which introduces human bias. To address this issue, this paper proposes an automatic interlayer identification method based on logging curve units, in P Oilfield. By analyzing the sedimentary and petrophysical characteristics of argillaceous and calcareous interlayers, along with their logging curve responses, multiple logging curves are integrated into a single comprehensive curve. This enables the automatic identification of both single-well and inter-well interlayers, achieving an identification accuracy of up to 90%. This method effectively improves the accuracy and efficiency of interlayer identification and demonstrates high application potential. Analyzing actual data from the P Oilfield, this study reveals the dominant role of interlayers in controlling the distribution of remaining oil in bottom-water reservoirs. It also summarizes three typical remaining oil distribution patterns: basal oil, dome oil, and cap oil. These findings provide practical guidance for subsequent oilfield development and enhanced recovery. This method not only offers an automated solution for interlayer identification in oilfields but also provides scientific evidence for precise decision-making in oilfield development. Full article
16 pages, 4394 KiB  
Article
Advanced Process Control Strategies for Efficient Methanol Production from Natural Gas
by Md Emdadul Haque and Srinivas Palanki
Processes 2025, 13(2), 424; https://doi.org/10.3390/pr13020424 - 5 Feb 2025
Viewed by 285
Abstract
Natural gas-to-methanol plants are receiving renewed interest with the significant increase in shale gas availability. Methanol serves as a crucial raw material for producing various industrial and consumer goods as well as key platform chemicals, including acetic acid, methyl tertiary butyl ether, dimethyl [...] Read more.
Natural gas-to-methanol plants are receiving renewed interest with the significant increase in shale gas availability. Methanol serves as a crucial raw material for producing various industrial and consumer goods as well as key platform chemicals, including acetic acid, methyl tertiary butyl ether, dimethyl ether, and methylamine. In this research, a dynamic model is developed for Natgasoline’s methanol manufacturing plant. A hierarchical control system comprising Dynamic Matrix Control (DMC) and a basic regulatory control loop is constructed using this dynamic model to minimize methanol losses and utility costs under various process upsets. A subspace identification methodology is used to develop rigorous DMCplus controller models. The simulation results in the ASPEN manufacturing software platform show that the DMCplus controller developed in this study can reduce methanol losses by 96% and utility requirements by 40%. The controller is robust to feed flow variations of ±10%. Furthermore, disturbances due to the variation in hydrogen content in the syngas are also successfully rejected by the controller. This hierarchical multivariable control system performs significantly better than the traditional regulatory PID control strategy in optimizing the methanol process under process constraints. Full article
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18 pages, 2229 KiB  
Article
Occurrence, Transport, and Risk Assessment of Brominated Flame Retardants in Northern Wetland Multimedia
by Bo Meng, Xi-Mei Lu, Jing-Wen Jia, Fei Chen, Zhi-Zhong Zhang, Shan-Shan Jia, Ming-Song Wu, Zi-Feng Zhang and Yi-Fan Li
Processes 2025, 13(2), 423; https://doi.org/10.3390/pr13020423 - 5 Feb 2025
Viewed by 441
Abstract
Current studies have paid extensive attention to the occurrence of brominated flame retardants (BFRs) in aquatic environments; however, there is a lack of exploration of BFRs in ice media in freshwater environments, and there are fewer studies on the distribution patterns and ecological [...] Read more.
Current studies have paid extensive attention to the occurrence of brominated flame retardants (BFRs) in aquatic environments; however, there is a lack of exploration of BFRs in ice media in freshwater environments, and there are fewer studies on the distribution patterns and ecological risks of BFRs in different media. In order to fill this gap in the current research status, this study conducted four seasonal samplings in the Songhua River wetland in Northeast China. The distribution and risk of 14 polybrominated diphenyl ethers (PBDEs) and 22 new brominated flame retardants (NBFRs) in water, ice, sediment, and soil were analyzed using liquid–liquid extraction sample pretreatment and gas chromatography–mass spectrometry instrumentation. A total of 18, 5, 8, 19, and 18 BFRs were detected in non-ice-covered water, ice-covered water, ice, sediment, and soil, respectively. NBFRs dominated contaminant concentrations in each medium. Significant correlations were found between BFRs in ice and subglacial water, suggesting that the sources of BFRs in these two media are similar and there is an exchange between them. The ice enrichment factor (IEF) revealed the water–ice distribution mechanism of BFRs, indicating that wetland ice acts as a temporary sink for 2-(Allyloxy)-1,3,5-tribromobenzene (ATE), 1,2-Dibromo-4-(1,2-dibromoethyl)cyclohexane (α-TBECH), 1,2,5,6-Tetrabromocyclooctane (TBCO), and 2-Bromoallyl 2,4,6-tribromophenyl ether (BATE). In order to achieve dynamic equilibrium, the exchange profile of BFRs between water and sediment requires the release of BFRs into water. The risk quotient (RQ) indicated that TBCO in water and ice poses a moderate risk to aquatic organisms, and its potential impact on wetland ecology cannot be ignored. Full article
(This article belongs to the Special Issue 1st SUSTENS Meeting: Advances in Sustainable Engineering Systems)
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54 pages, 3811 KiB  
Review
Evolution and Latest Trends in Cooling and Lubrication Techniques for Sustainable Machining: A Systematic Review
by Samuel Polo, Eva María Rubio, Marta María Marín and José Manuel Sáenz de Pipaón
Processes 2025, 13(2), 422; https://doi.org/10.3390/pr13020422 - 5 Feb 2025
Viewed by 400
Abstract
This document presents a review on cooling and lubrication methods in machining. A systematic search of information related to these methods was carried out based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology. The importance of the sustainability of [...] Read more.
This document presents a review on cooling and lubrication methods in machining. A systematic search of information related to these methods was carried out based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology. The importance of the sustainability of machining processes is highlighted, as they represent between 10 and 17% of the total manufacturing cost of the final part and have negative environmental and health impacts. Although dry machining completely eliminates the use of cutting fluids, in many cases it produces unsatisfactory results due to the increase in temperature inside the tool, which requires prior analysis to ensure its viability compared to conventional techniques. On the other hand, semi-dry machining, which significantly reduces the volume of cutting fluids, is a more competitive alternative, with results similar to those of conventional machining. Other sustainable cooling and lubrication methods are also being investigated, such as cryogenic and high-pressure cooling, which offer better machining results than conventional processes. However, they have a high initial cost and further research is needed to integrate them into industry. While the combination of these cooling and lubrication methods could lead to improved results, there is a notable lack of comprehensive studies on the subject. Full article
(This article belongs to the Special Issue Process Automation and Smart Manufacturing in Industry 4.0/5.0)
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16 pages, 3595 KiB  
Review
Polycrystalline Diamond Composite Bit Technology for Sustainable Work
by Xiaoao Liu, Guodong Ji, Liyuan Yang, Haitao Ren, Qiang Wu, Jinping Yu and Kuilin Huang
Processes 2025, 13(2), 421; https://doi.org/10.3390/pr13020421 - 5 Feb 2025
Viewed by 322
Abstract
Reducing the auxiliary drilling time and improving the drilling efficiency are not only important technical means to enhance the development and deep exploration of oil and gas reserves, but also have significant implications for ensuring energy security. Bottom hole self-renewal drill bit technology [...] Read more.
Reducing the auxiliary drilling time and improving the drilling efficiency are not only important technical means to enhance the development and deep exploration of oil and gas reserves, but also have significant implications for ensuring energy security. Bottom hole self-renewal drill bit technology is a new technology that does not require the retrieval of drills from the well bottom, instead directly updating worn drill bits in place. Through the self-renewing structure of the drill bit, the sustainability of the drill bit can be increased. Conducting research on this technology is expected to overcome the technical issues related to the short useable life of drill bits, thus promoting single-trip drilling technology. This article summarizes the scientific progress made by researchers in self-renewal Polycrystalline Diamond Composite (PDC) drill bit technology; for example, the American National Oilwell Varco (NOV) company has developed a mobile self-renewal cone bit technology and introduced the structural characteristics and working principles of three types of rotating self-renewal drill bits: rack-driven, worm-driven, and ratchet-driven. This study compares and analyzes the advantages and disadvantages of these three rotary types of PDC drill bits, providing a detailed introduction to the working principles and modes of the triggering, transmission, limit and locking, and renewal structure devices of the drill bit. Relevant suggestions are proposed for the development of bottom hole self-renewal PDC drill bit technology; namely, strengthening research efforts relating to the intelligent judgment and recognition of cutting tooth wear of the drill bit, as well as the integration of multiple technologies. The sustainability of these novel bits can provide technical support for the development of single-trip drilling technology for deep formations, improve the service life of bits in deep formations that are difficult to drill, and contribute to the efficient development of deep-sea energy resources worldwide. Full article
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32 pages, 4103 KiB  
Review
Strategic Selection of a Pre-Reduction Reactor for Increased Hydrogen Utilization in Hydrogen Plasma Smelting Reduction
by Bernhard Adami, Felix Hoffelner, Michael Andreas Zarl and Johannes Schenk
Processes 2025, 13(2), 420; https://doi.org/10.3390/pr13020420 - 5 Feb 2025
Viewed by 271
Abstract
The hydrogen plasma smelting reduction process has the potential to drastically reduce the CO2 emissions of the steel industry by using molecular, atomic and ionized hydrogen as a reducing agent for iron ores. To increase the hydrogen and thermal efficiency of the [...] Read more.
The hydrogen plasma smelting reduction process has the potential to drastically reduce the CO2 emissions of the steel industry by using molecular, atomic and ionized hydrogen as a reducing agent for iron ores. To increase the hydrogen and thermal efficiency of the process, a pre-reduction and pre-heating stage should be incorporated in a future upscaling of an existing HPSR demonstration plant within the scope of the “SuSteel follow-up” project to a target capacity of 200 kg/h of iron ore. The determination of the optimal process parameters is followed by a review of possible reactor types. A fluidized bed cascade, a cyclone cascade and a rotary kiln are compared for this purpose. Their applicability for the hydrogen plasma smelting is discussed, based on their fundamental design and operational procedures. Additionally, critical features of the different reactor types are outlined. A cyclone cascade with at least 3 stages is proposed to be the optimal reactor for pre-heating and pre-reducing the input material for the upscaled hydrogen plasma smelting reduction demonstration plant, based on the assessment. Full article
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22 pages, 5818 KiB  
Article
Life Cycle Assessment of Primary Aluminum Production
by Xuan Lian, Hanchen Gao, Leiting Shen, Yilan Yu, Yilin Wang and Zhihong Peng
Processes 2025, 13(2), 419; https://doi.org/10.3390/pr13020419 - 5 Feb 2025
Viewed by 277
Abstract
Life cycle assessment (LCA) is used to quantitatively analyze the energy consumption and environmental impact of primary aluminum production in China, the United States, and Europe, as well as global average. The results indicate that electricity and fuel contribute more than 60% of [...] Read more.
Life cycle assessment (LCA) is used to quantitatively analyze the energy consumption and environmental impact of primary aluminum production in China, the United States, and Europe, as well as global average. The results indicate that electricity and fuel contribute more than 60% of the environmental impact of bauxite mining; steam is the greatest contributor to the environmental impact of alumina production by the Bayer process, with a result exceeding 35%; and electricity contributes >50% of the environmental impact of aluminum electrolysis. The environmental impact of primary aluminum production in China is 1.2 times the global average. The contributions of the three stages of primary aluminum production to the total environmental impact of the process in China are, in descending order, aluminum electrolysis (64.33%), alumina production (33.09%), and bauxite mining (2.58%). If the proportion of thermal power in the electricity source structure is reduced from 60% to 0%, the contribution of electricity to the environmental impact of primary aluminum production will decrease from 38% to 2%, and the total environmental impact will decrease by 73%. Therefore, energy conservation and emissions reduction can be realized through the optimization of the power generation structure, adoption of clean energy production, and improvement of the heat utilization rate in production processes. Full article
(This article belongs to the Special Issue Non-ferrous Metal Metallurgy and Its Cleaner Production)
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29 pages, 14711 KiB  
Article
Structural Engineering of π-Linker Aromaticity in Anthanthrene-Based Dyes with D–π–A Configuration: DFT Investigation to Enhance Charge Transfer in DSSCs
by Nuha Wazzan
Processes 2025, 13(2), 418; https://doi.org/10.3390/pr13020418 - 5 Feb 2025
Viewed by 288
Abstract
The development of efficient dyes for photon harvesting in dye-sensitized solar cells (DSSCs) is a critical area of research with the potential to enhance renewable energy technologies. This manuscript presents a novel approach to engineering dye structures (abbreviated as D2 dye features, an [...] Read more.
The development of efficient dyes for photon harvesting in dye-sensitized solar cells (DSSCs) is a critical area of research with the potential to enhance renewable energy technologies. This manuscript presents a novel approach to engineering dye structures (abbreviated as D2 dye features, an anthanthrene core with a resonance energy of ER = 694 kJ/mol and a reported power conversion efficiency (η) of 5.27%) by systematically replacing an anthanthrene core with various aromatic cores, aiming to understand the influence of resonance energy on molecular performance. By designing seven new dyes with resonance energies ranging from 255 to 529 kJ/mol, we conducted in-depth computational studies using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TDDFT) to explore the effects of π-aromatic linkers on their electronic properties. Our findings reveal key insights into intermolecular charge-transfer (ICT) mechanisms and how they relate to the resonance energy of dye cores, highlighting the significance of balanced charge mobilities in optimizing optoelectronic characteristics, as shown by the D9 dye with a naphthacene core. Full article
(This article belongs to the Special Issue Modeling, Operation and Control in Renewable Energy Systems)
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20 pages, 6955 KiB  
Article
Numerical Simulation and Experimental Testing of the Strength of the Piston-Returning Spherical Joint Pair in a High-Speed Axial Piston Pump
by Shaonian Li, Fuhao Li, Longtao Yang, Kaifeng Wang and Liting Fu
Processes 2025, 13(2), 417; https://doi.org/10.3390/pr13020417 - 5 Feb 2025
Viewed by 246
Abstract
The piston-returning spherical joint pair in an axial piston pump continuously bears alternating loads generated by conversions between high and low pressure. If its strength fails, then the axial piston pump cannot function normally. Therefore, we performed numerical simulations and laboratory experiments to [...] Read more.
The piston-returning spherical joint pair in an axial piston pump continuously bears alternating loads generated by conversions between high and low pressure. If its strength fails, then the axial piston pump cannot function normally. Therefore, we performed numerical simulations and laboratory experiments to investigate the strength properties of the piston-returning spherical joint pair components of an axial piston pump. The results show that when the piston is in the transition area from oil suction to oil discharge, the maximum deformation and stress of the slipper are located on the inner surface of the slipper spherical socket, and the maximum deformation value is 2.523 μm. When the piston is in the transition area from oil discharge to oil suction, the maximum deformation and stress of the slipper are located at the closing part of the slipper, and the maximum deformation value is 1.959 μm. The maximum deformation of the piston at both positions is located at the bottom of the piston, with values of 11.622 μm and 3.8512 μm, respectively. The maximum stress of the piston is located in the neck of the piston. The deformation at the spherical socket closure of the slipper increases with the increase in the pushing–pulling force, and this relationship is nonlinear. The maximum deformation at the spherical socket closure is smallest for the manganese brass slipper, is larger for the tin bronze slipper, and is largest for the ordinary brass slipper. The maximum deformation at the spherical socket closure of the slipper obtained by the strength test is greater than the simulation result. These research conclusions can serve as a reference for the design of piston-returning spherical joint pairs in axial piston pumps. Full article
(This article belongs to the Section Energy Systems)
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26 pages, 10695 KiB  
Article
Abrasive Flow Material Removal Mechanism Under Multifield Coupling and the Polishing Method for Complex Titanium Alloy Surfaces
by Yufei Fu, Rui Wang, Zhongfei Wang, Bingjun Zheng and Li Zhang
Processes 2025, 13(2), 416; https://doi.org/10.3390/pr13020416 - 5 Feb 2025
Viewed by 269
Abstract
This study addresses the challenge of uneven surface quality on the concave and convex regions during the precision machining of titanium alloy thin-walled complex curved components. An electrostatic field-controlled liquid metal-abrasive flow polishing method is proposed, which is examined through both numerical simulations [...] Read more.
This study addresses the challenge of uneven surface quality on the concave and convex regions during the precision machining of titanium alloy thin-walled complex curved components. An electrostatic field-controlled liquid metal-abrasive flow polishing method is proposed, which is examined through both numerical simulations and experimental investigations. Initially, a material removal model for the liquid metal-abrasive flow under electrostatic field control is developed, with computational fluid dynamics (CFD) and discrete phase models employed for the numerical simulations. Subsequently, the motion characteristics of liquid metal droplets under varying amplitudes of alternating electric fields are experimentally observed within the processing channel. This serves to validate the effectiveness of the proposed method in enhancing surface quality uniformity across the concave and convex regions of titanium alloy thin-walled complex curved components. Our results demonstrate that by controlling the distribution of the electric field in regions with varying flow strengths, the roughness differences between the concave and convex surfaces of the workpiece are reduced to varying degrees. Specifically, in the experimental group subjected to a 24 V alternating electric field, the roughness difference is minimized to 58 nm, representing a 44% reduction compared to conventional abrasive flow polishing. These findings indicate that the proposed electrostatic field-controlled liquid metal-abrasive flow polishing method significantly enhances the uniformity of surface polishing on concave and convex areas of titanium alloy thin-walled complex curved components. Full article
(This article belongs to the Section Materials Processes)
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21 pages, 2727 KiB  
Article
Technical and Economic Analysis of a Novel Integrated Energy System with Waste Tire Pyrolysis and Biogas
by Cheng Xin, Jun Liu, Tianqiong Chen, Heng Chen, Huijuan Huo, Shuo Wang and Yudong Wang
Processes 2025, 13(2), 415; https://doi.org/10.3390/pr13020415 - 5 Feb 2025
Viewed by 304
Abstract
To reduce dependence on fossil fuels, cope with the growing energy demand, and reduce greenhouse gas emissions, this paper innovatively designs a novel integrated energy system integrating anaerobic digestion of animal manure, fuel cell technology, gas turbine, and tire pyrolysis. The system maximizes [...] Read more.
To reduce dependence on fossil fuels, cope with the growing energy demand, and reduce greenhouse gas emissions, this paper innovatively designs a novel integrated energy system integrating anaerobic digestion of animal manure, fuel cell technology, gas turbine, and tire pyrolysis. The system maximizes the energy potential of biogas while synergistically treating waste tires, improving waste management’s flexibility, efficiency, and economic viability through multiple outputs such as electricity and by-products, subsystem synergies, equipment sharing, and economies of scale. Thermodynamic performance and economic feasibility are analyzed using Aspen Plus V14 simulation modeling, ensuring the system’s technical and economic viability. In this study, the simulation model of the system is established, and the techno-economic benefits of the system are analyzed. The simulation results show that the net electric power output of the system is 444.79 kW. Combined with the contribution of pyrolysis products, the system’s total efficiency reaches 70.88%. In only 4.79 years, the initial investment can be recovered, and in its 25-year service life, the system has realized a profit of 2,939,130 USD. The system realizes the energy and quality matching between different thermal processes through indirect collaborative treatment of different solid wastes, improves the conversion efficiency of biogas energy, co-treats waste tires, and reduces environmental pollution. Full article
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15 pages, 10351 KiB  
Article
Life Prediction of Penstock Based on Strength Simulation and Sediment Wear Test
by Liang Peng, Jiayang Pang, Ziyao Zhou, Haiqi Wang, Shenhui Li, Wenping Xiang, Xutao Yi and Xiaobing Liu
Processes 2025, 13(2), 414; https://doi.org/10.3390/pr13020414 - 4 Feb 2025
Viewed by 291
Abstract
A hydropower station, which has been in operation for over 50 years, has a penstock located in the plant’s open pipe section. Recently, concerns have been raised regarding the potential risks to the penstock’s safe operation due to wall thinning caused by abrasion. [...] Read more.
A hydropower station, which has been in operation for over 50 years, has a penstock located in the plant’s open pipe section. Recently, concerns have been raised regarding the potential risks to the penstock’s safe operation due to wall thinning caused by abrasion. A series of stress tests, strength mathematical model analysis, and sediment erosion tests were performed on the penstock during turbine load rejection events. A stress and strain monitoring system for the steel pressure pipe was developed, enabling real-time monitoring and providing a warning function. The current wall thickness of the steel pressure pipe is about 28 mm. The results indicate that a pipe rupture is unlikely under any load rejection scenario. However, if the wall thickness is reduced to around 24 mm, the maximum equivalent stress of the pipe will approach the safety limit during load rejection. The sediment erosion test showed an erosion rate of 3.509 × 10–5 mm/h at an average sediment concentration of 0.63 kg/m3. Assuming no other factors, such as an increase in river sediment concentration, and based on the design specifications of the steel pressure pipe and the annual average sediment concentration of 0.63 kg/m3, it is projected that the open pipe section can be operated for about 19 years before the wall thickness reaches 24 mm. It is recommended that once the wall thickness reaches 24 mm due to erosion or other factors, the pipeline system undergoes maintenance or replacement. The findings provide significant guidance for the operation of similar power stations. Full article
(This article belongs to the Section Materials Processes)
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