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Processes, Volume 10, Issue 4 (April 2022) – 182 articles

Cover Story (view full-size image): Flash calculations that include phase split and phase classifications for n-Octane/Water and Paraffinic Aromatic Synthetic Naphtha (PASN)/Water offer challenges. Computations to establish two-phase and three-phase regions, as well as their transitions, were considered in a recent article involving machine learning (Lopez Zamora et al, 2021). The present study on face split evaluations focuses on a) the lack of numerical convergence of traditional calculations based on Rachford–Rice-derived surfaces and b) the successful implementation of a machine-learning-based method using a K-Nearest-Neighbor (KNN) algorithm that is applied to the experimental data obtained in a CREC-VL cell. View this paper
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17 pages, 5937 KiB  
Article
Numerical Investigation of the Cleaning Flame Jet and Formation of the Molten Pool in the Corner Scarfing Process of the Casting Slab
by Cong Wang, Yongqiang Zhang, Aiyun Gao, Jieyu Zhang and Bo Wang
Processes 2022, 10(4), 798; https://doi.org/10.3390/pr10040798 - 18 Apr 2022
Viewed by 1901
Abstract
The corner defects in the casting slab greatly influence the product quality. These defects may extend during the heating and rolling process and even result in the discarding of the rolled plate as scrap. A corner cleaning equipment based on the scarfing machine [...] Read more.
The corner defects in the casting slab greatly influence the product quality. These defects may extend during the heating and rolling process and even result in the discarding of the rolled plate as scrap. A corner cleaning equipment based on the scarfing machine is proposed to eliminate the defects in slab corners for producing high-quality steel. Unlike the flat surface scarfing process, the flame jet and the shape of the molten pool have an essential impact on the effectiveness of the flame cleaning in the corner of the casting slab. A three-dimensional fully coupled model for the flame cleaning nozzle is developed to simulate the flow pattern of the flame jet, Oxygen concentration distribution, and temperature field in the corner of the slab. The simulated flame jet flow field and temperature results agreed well with the factory trial results. Additionally, a three-dimensional thermal model for simulation of the molten pool formed by flame cleaning in the corner of the casting slab has also been developed. For the sake of simplicity, the 2D elliptic and 3D Gauss heat source models are used to simulate the flame heating on the upper and right surfaces of the slab corner and the reaction heating between oxygen and heated iron along the corner, respectively. The simulation results show that the length is 58.1 mm and 57.9 mm on both sides and the corner melting depth is 29.9 mm. The error is 7.04%. The numerical simulation results showed good agreement with the factory trial results, indicating that the proposed models of the flame jet and the heat sources analysis are feasible to study the flame cleaning process of the slab corner, it provides the scientific theoretical basis for the design and practical application of corner scarfing machine. Full article
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11 pages, 5248 KiB  
Article
Analysis of the Formation Mechanism of Surface Cracks of Continuous Casting Slabs Caused by Mold Wear
by Jingyi Zhou, Liguang Zhu, Ligen Sun, Bo Wang and Pengcheng Xiao
Processes 2022, 10(4), 797; https://doi.org/10.3390/pr10040797 - 18 Apr 2022
Cited by 2 | Viewed by 2457
Abstract
Surface cracks are easily produced after friction between continuous casting billets and copper layers in mold cavity, but the formation mechanism is not clear. Based on a steel-based hot-dip copper plating experiment, this study simulated the action behavior of copper adhering to the [...] Read more.
Surface cracks are easily produced after friction between continuous casting billets and copper layers in mold cavity, but the formation mechanism is not clear. Based on a steel-based hot-dip copper plating experiment, this study simulated the action behavior of copper adhering to the surface of a continuous casting billet after mold wear and systematically analyzed the formation mechanism of cracks caused by copper infiltration on the surface of the continuous casting billet. It is shown that when the copper liquid adheres to the surface of the slab, in addition to the diffusion of Cu in the steel, Fe is also dissolved in the copper liquid, accelerating the solidification of the copper liquid on the surface of the slab and forming a stable fusion combination between copper and steel. At the same time, due to the enrichment of the Fe-C phase and a large number of vacancies at the grain boundary, the grain boundary becomes the dominant area of copper–steel fusion bonding. For a continuous casting process in which the temperature is kept higher than 900 ℃, Cu’s solubility is high and the diffusion coefficient is very low in Fe, which makes it very difficult for Cu accumulated in the grain boundary to diffuse into the steel matrix during the continuous casting process, resulting in a grain boundary with a greatly weakened strength becoming the origin of cracks in the bending and straightening deformation of the billet. Full article
(This article belongs to the Special Issue High-Efficiency and High-Quality Continuous Casting Processes)
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16 pages, 1190 KiB  
Article
Targeting on Different Characteristic Continuous Variables in Process Transition for Ethylene Column with Wide-Range Feed Fluctuation
by Xin-Yi Cao, Feng Xu and Xiong-Lin Luo
Processes 2022, 10(4), 796; https://doi.org/10.3390/pr10040796 - 18 Apr 2022
Cited by 1 | Viewed by 1432
Abstract
For the study of the transition strategies of continuous chemical processes, both continuity and dynamic characteristics in the physical sense are critical. The continuous transition strategy has a higher information density and can describe the real situation as closely as possible. In addition, [...] Read more.
For the study of the transition strategies of continuous chemical processes, both continuity and dynamic characteristics in the physical sense are critical. The continuous transition strategy has a higher information density and can describe the real situation as closely as possible. In addition, the accuracy of the dynamic characteristics is necessary because the process transition is the study of the dynamic system processes. However, existing transition strategies have certain shortcomings. Dynamic optimization can obtain transition strategies with different characteristics but no physical meaning and a frequency domain-based analytical approach can acquire a continuous transition strategy with physical meaning, but its dynamic characteristics are the same. Therefore, by integrating the advantages of the existing strategies, a new transition strategy has been presented, which possesses different dynamic characteristics and continuity synchronous with physical significance. When process transition occurs, the proposed strategy results in less fluctuation and can quickly reach and maintain a steady state. Furthermore, the strategy is also suitable for the rapid application of different transition processes in the same plant. The performance of the transition strategies is evaluated through research on a continuous feed ethylene column. Full article
(This article belongs to the Topic Bioreactors: Control, Optimization and Applications)
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16 pages, 6951 KiB  
Article
Investigation on Creep Behavior of Aggregates of Loess by a Discrete Element Method
by Jian-Qiang Sun, Xi-An Li, Mei-Le Bi, Kai-Xuan Zhang and Jing Zhang
Processes 2022, 10(4), 795; https://doi.org/10.3390/pr10040795 - 18 Apr 2022
Viewed by 1641
Abstract
In loess the aggregate is the basic structural unit, and its stability is an important factor affecting the composition, water stability and strength of loess. However, due to the difficulty of sample preparation, few scholars have done independent research on it. In this [...] Read more.
In loess the aggregate is the basic structural unit, and its stability is an important factor affecting the composition, water stability and strength of loess. However, due to the difficulty of sample preparation, few scholars have done independent research on it. In this manuscript, a numerical model of aggregate is constructed by the discrete element method. Under the continuous action of certain stress, the uninterrupted development process of sample deformation with time was observed, that is, the creep of aggregate structures. The results show that the creep of aggregates is closely related to the relative movement, rotation and rearrangement of internal structural elements, and the most intuitive mesoscopic evolution of the adjustment process of structural elements is the change of contact number, namely the coordination number. The microscopic parameters and evolutionary characteristics of fabric can reveal the microscopic mechanism behind the macroscopic creep phenomenon. With the creep process, the creep stress is gradually borne by the normal contact force rather than the tangential contact force and has anisotropic characteristics. As a result of creep, the contact points of particles increase, and the interaction between aggregates changes from point contact to overlap contact. The constraint between aggregates increases, and the skeleton tends to be a more stable structure, which can bear a larger load. Full article
(This article belongs to the Special Issue DEM Simulations and Modelling of Granular Materials)
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19 pages, 3674 KiB  
Article
Amine-Based Deep Eutectic Solvents for Alizarin Extraction from Aqueous Media
by Nihal Yasir, Amir Sada Khan, Noor Akbar, Muhammad Faheem Hassan, Taleb H. Ibrahim, Mustafa Khamis, Ruqaiyyah Siddiqui, Naveed Ahmed Khan and Paul Nancarrow
Processes 2022, 10(4), 794; https://doi.org/10.3390/pr10040794 - 18 Apr 2022
Cited by 3 | Viewed by 2362
Abstract
Alizarin dye is toxic and has a negative influence on human life and the environment. Consequently, the scientific community faces a difficult issue in developing efficient approaches for removing alizarin from water streams. Six distinct deep eutectic solvents (DESs) containing different hydrogen bond [...] Read more.
Alizarin dye is toxic and has a negative influence on human life and the environment. Consequently, the scientific community faces a difficult issue in developing efficient approaches for removing alizarin from water streams. Six distinct deep eutectic solvents (DESs) containing different hydrogen bond acceptors (HBAs), namely trioctylphosphine, trioctylamine and trihexylamine, and two hydrogen bond donors (HBDs), namely salicylic acid and malonic acid, were used to rapidly remove alizarin from high concentration solutions up to 2000 mg/L at room temperature using the liquid–liquid micro-extraction method (LLE). DES-3 had the highest extraction efficiency for alizarin among the other synthesized DESs. The effect of process variables such pH, contact time, dye initial concentration, volume ratio, temperature and salt on alizarin extraction efficiency from water stream was explored, optimized and reported. Statistical analysis was conducted to ensure the accuracy of values for the optimized parameters. For a 1000 mg/L solution of alizarin with a DES/alizarin volume ratio of 1:10 at room temperature, the maximum elimination of 98.02 percent was achieved in 5 min. FTIR was used to analyze the structural properties of DES and the interaction between DES and alizarin. The thermal stability of DES-3 was determined using thermogravimetric analysis (TGA) and indicated that DES-3 has excellent thermal stability up to 320 °C. Human saline was used to test the toxicity of the synthesized DES in vitro. It was determined that synthesized DES is less harmful and more effective at removing alizarin. Full article
(This article belongs to the Special Issue Pollutant Removal and Separation Processes in Chemical Engineering)
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21 pages, 4692 KiB  
Article
A New LC-MS Method for Evaluating the Efficacy of Pesticide Residue Removal from Fruit Surfaces by Washing Agents
by Magdalena Zarębska, Zofia Hordyjewicz-Baran, Tomasz Wasilewski, Ewa Zajszły-Turko and Natalia Stanek
Processes 2022, 10(4), 793; https://doi.org/10.3390/pr10040793 - 18 Apr 2022
Cited by 8 | Viewed by 3458
Abstract
Modern agriculture uses pesticides to improve the quality and quantity of crops. However, pesticide residues can remain on agricultural products, posing very serious risks to human health and life. It is recommended to wash fruits and vegetables before consumption. To assess the removal [...] Read more.
Modern agriculture uses pesticides to improve the quality and quantity of crops. However, pesticide residues can remain on agricultural products, posing very serious risks to human health and life. It is recommended to wash fruits and vegetables before consumption. To assess the removal efficacy of pesticide residue, a sensitive and reliable method based on ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed and optimized for the simultaneous determination of four pesticide residues (acetamiprid, boscalid, pyraclostrobin, and pendimethalin). Isotope-labeled standards were used to validate the method in terms of recovery, linearity, matrix effects, precision, and sensitivity. The mean recovery values for both low-quality control (LQC) and high-quality control (HQC) transitions were in the range of 89–105%, and the intra-day precision was less than 13.7%. The limits of detection (LOD) and quantification (LOQ) were 0.003 mg/kg and 0.01 mg/kg, respectively. The proposed method is suitable for evaluating the quality of detergents for removing pesticide residues from fruit surfaces. Full article
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12 pages, 3190 KiB  
Article
The Impact of Berberine Pharmaceutical Wastewater on Aerobic Granules Formation: Change of Granules’ Size
by Ping Zeng, Yan Wang, Yongqiang Liu, Juan Li, Fenghua Liu, Ming Chang and Yizhang Zhang
Processes 2022, 10(4), 792; https://doi.org/10.3390/pr10040792 - 18 Apr 2022
Cited by 1 | Viewed by 1535
Abstract
As important parameters in the characterization of aerobic granulation, the shape and average diameter were related to substrates. The previous studies disclosed that the morphology change in aerobic granules was the result of growth and the relatively strong hydrodynamic shear force. No further [...] Read more.
As important parameters in the characterization of aerobic granulation, the shape and average diameter were related to substrates. The previous studies disclosed that the morphology change in aerobic granules was the result of growth and the relatively strong hydrodynamic shear force. No further exploration of the size distribution of the aerobic granules has been conducted. To better understand the impact of toxic compounds on aerobic granules’ growth during their formation, the properties of aerobic granules were traced over 81 days in 3 sequencing batch reactors fed with acetate and berberine wastewater, especially the particle size and size distribution. The results showed that the aerobic granules were cultivated by the simulated acetate wastewater (R1), simulated berberine wastewater (R2), and effluent from an anaerobic baffled reactor (ABR) reactor which was fed with industrial berberine wastewater (R3). The reactors exhibited different COD removal efficiencies, and the MLSS and MLVSS values affected by the different substrates which were in an order of R1 > R2 > R3. However, the SVI and SOUR, which were affected by several factors, showed more complicated results. The aerobic granules had the lowest microbial activity (SOUR), while the aerobic granules in R3 had the lowest settling ability among the three kinds of granules. For the three reactors with different influent compositions, the aerobic granulation process displayed a three-stage process separately. Compared with the granules fed with berberine wastewater, the granules fed with acetate in a stable operation period showed more independence from other periods.The size distribution was affected by substrates. The aerobic granules with a range of 0.3–1.0 µm occupied 77.0%, 67.0%, and 35.7% of the volume for R1, R2, and R3, respectively. The biomass less than 0.3 µm occupied 59.1% volume in R3. The components of the substrate had a great influence on the growth of aerobic granules, not only on the diameter but also on the size distribution. Full article
(This article belongs to the Section Environmental and Green Processes)
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19 pages, 4263 KiB  
Article
Research on Fault Diagnosis of PST Electro-Hydraulic Control System of Heavy Tractor Based on Support Vector Machine
by Huiting Ni, Liqun Lu, Meng Sun, Xin Bai and Yongfang Yin
Processes 2022, 10(4), 791; https://doi.org/10.3390/pr10040791 - 18 Apr 2022
Cited by 4 | Viewed by 2066
Abstract
Due to the harsh working environment of the tractor, the transmission can often be faulty. In order to ensure the reliability of its operation, it must be monitored and the fault discovered. In this paper, the support vector machine (SVM) method is used. [...] Read more.
Due to the harsh working environment of the tractor, the transmission can often be faulty. In order to ensure the reliability of its operation, it must be monitored and the fault discovered. In this paper, the support vector machine (SVM) method is used. The eigenvector conversion of the original data uses the following eigenvectors: Three fault modes (leakage fault of shift clutch hydraulic cylinder, blockage fault of oil passage, and blockage fault of proportional valve spool) are identified in matrix and laboratory (MATLAB) with the help of the library for support vector machines (LibSVM) toolkit, and the classification accuracy of test samples is 90%. The normal mode of the PST electro-hydraulic system and the three kinds of fault modes mentioned above are discriminated against, and the correct rate of fault diagnosis reaches 95%, which meets the needs of practical engineering. Analysis of the fault recording data of the power shifting transmission shift solenoid valve shows that the difference between fault pressure data and normal data is small, and the value of traffic data is greater. This method can realize the fault mode online recognition based on controller area network (CAN) communication, and the research results provide a theoretical basis for the fault diagnosis of the PST electro-hydraulic control system. Full article
(This article belongs to the Special Issue Application of Fuzzy Control in Computational Intelligence)
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14 pages, 1506 KiB  
Article
Evaluating the Energy Efficiency and Environmental Impact of COVID-19 Vaccines Coolers through New Optimization Indexes: Comparison between Refrigeration Systems Using HFC or Natural Refrigerants
by Alexandre F. Santos, Pedro D. Gaspar and Heraldo J. L. de Souza
Processes 2022, 10(4), 790; https://doi.org/10.3390/pr10040790 - 17 Apr 2022
Cited by 2 | Viewed by 2731
Abstract
COVID-19 vaccines are used worldwide to promote immunity and, in that sense, vaccination is a step forward toward ending the pandemic. Nevertheless, current vaccines must be ultra-cold or cold-stored. Vaccine coolers’ energy demand and greenhouse gas emissions lead to a significant environmental impact. [...] Read more.
COVID-19 vaccines are used worldwide to promote immunity and, in that sense, vaccination is a step forward toward ending the pandemic. Nevertheless, current vaccines must be ultra-cold or cold-stored. Vaccine coolers’ energy demand and greenhouse gas emissions lead to a significant environmental impact. This article predicts the environmental and energy impacts of some COVID-19 vaccines: Moderna, Janssen, CoronaVac, Pfizer, AstraZeneca–Oxford–Covishield, and Sputnik V, in terms of carbon dioxide emissions using a new approach for the TEWI (Total Equivalent Warming Impact) methodology, with several options of refrigerants from halogenated to natural fluids such as propane, which is natural gas with low GWP (global warming potential). Through the application of new optimization indexes, it is concluded that the evaporation temperature of the refrigerant gas has a great influence on the sizing of the coolers. For example, for the same number of vaccines, the thermal load of Pfizer is more than double that of AstraZeneca–Covishield, CoronaVac, or Janssen, while the direct environmental impact is seven times greater. Another relevant factor is the choice of refrigerant. For example, the greenhouse effect varies greatly for the same brand of vaccine. The Moderna vaccine’s global warming potential (GWP) is 776 times higher using R-449A gas than using R-290 (propane gas). In Brazil, the refrigerators used to store the Pfizer vaccine have a total TEWI almost two times higher than the total TEWI of refrigerators using propane to store the Janssen vaccine. At this time of the pandemic, these optimization indexes can be used to support important decisions regarding the future selection of vaccine brands considering the energy consumption and environmental impact required for their storage. Full article
(This article belongs to the Special Issue Optimization Algorithms Applied to Sustainable Production Processes)
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14 pages, 2656 KiB  
Article
Synthesis and Characterization of Bi2WxMo1−xO6 Solid Solutions and Their Application in Photocatalytic Desulfurization under Visible Light
by Artem S. Belousov, Evgeny V. Suleimanov, Alina A. Parkhacheva, Diana G. Fukina, Andrey V. Koryagin, Dmitry N. Titaev and Mikhail A. Lazarev
Processes 2022, 10(4), 789; https://doi.org/10.3390/pr10040789 - 17 Apr 2022
Cited by 9 | Viewed by 2213
Abstract
Photocatalytic oxidative desulfurization has attracted much attention in recent years due to the continuous tightening of the sulfur content requirements in motor fuels and the disadvantages of the industrial hydrodesulfurization process. This work is devoted to the investigation of the photocatalytic activity of [...] Read more.
Photocatalytic oxidative desulfurization has attracted much attention in recent years due to the continuous tightening of the sulfur content requirements in motor fuels and the disadvantages of the industrial hydrodesulfurization process. This work is devoted to the investigation of the photocatalytic activity of Bi2WxMo1−xO6 solid solutions (x = 1, 0.75, 0.5, 0.25, 0) in the oxidative desulfurization of hydrocarbons under visible light irradiation using hydrogen peroxide as an oxidant. The synthesized photocatalysts were characterized in detail using XRD, SEM, EDS, low-temperature nitrogen adsorption–desorption, and DRS. It was shown that the use of solid solutions Bi2WxMo1−xO6 with x = 0.5–0.75 leads to the complete oxidation of organosulfur compounds to CO2 and H2O within 120 min. The high photocatalytic activity of solid solutions (x = 0.5–0.75) is attributed to their ability to absorb more visible light, the presence of the corner-shared [Mo/WO6] octahedral layers, which may promote the generation and separation of photogenerated charges, and the hierarchical 3D flower-like structure. The reaction mechanism of the desulfurization was also analyzed in this work. Full article
(This article belongs to the Section Catalysis Enhanced Processes)
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21 pages, 1058 KiB  
Review
Sewage-Water Treatment and Sewage-Sludge Management with Power Production as Bioenergy with Carbon Capture System: A Review
by Israel Bernardo S. Poblete, Ofélia de Queiroz F. Araujo and José Luiz de Medeiros
Processes 2022, 10(4), 788; https://doi.org/10.3390/pr10040788 - 17 Apr 2022
Cited by 12 | Viewed by 7071
Abstract
Sewage-water treatment comprehends primary, secondary, and tertiary steps to produce reusable water after removing sewage contaminants. However, a sewage-water treatment plant is typically a power and energy consumer and produces high volumes of sewage sludge mainly generated in the primary and secondary steps. [...] Read more.
Sewage-water treatment comprehends primary, secondary, and tertiary steps to produce reusable water after removing sewage contaminants. However, a sewage-water treatment plant is typically a power and energy consumer and produces high volumes of sewage sludge mainly generated in the primary and secondary steps. The use of more efficient anaerobic digestion of sewage water with sewage sludge can produce reasonable flowrates of biogas, which is shown to be a consolidated strategy towards the energy self-sufficiency and economic feasibility of sewage-water treatment plants. Anaerobic digestion can also reduce the carbon footprint of energy sources since the biogas produced can replace fossil fuels for electricity generation. In summary, since the socio-economic importance of sewage treatment is high, this review examined works that contemplate: (i) improvements of sewage-water treatment plant bioenergy production and economic performances; (ii) the exploitation of technology alternatives for the energy self-sufficiency of sewage-water treatment plants; (iii) the implementation of new techniques for sewage-sludge management aiming at bioenergy production; and (iv) the implementation of sewage-water treatment with bioenergy production and carbon capture and storage. Full article
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24 pages, 1705 KiB  
Article
Environmental Benefits of Air Emission Reduction in the Waste Tire Management Practice
by Jasmina Ćetković, Slobodan Lakić, Miloš Žarković, Radoje Vujadinović, Miloš Knežević, Angelina Živković and Jelena Cvijović
Processes 2022, 10(4), 787; https://doi.org/10.3390/pr10040787 - 17 Apr 2022
Cited by 10 | Viewed by 3230
Abstract
Montenegro faces serious challenges in terms of waste tire management. The main goal of our paper is to consider the financial and economic justification of the implementation of the first phase of the project of collection, takeover and transport, sorting, and storage of [...] Read more.
Montenegro faces serious challenges in terms of waste tire management. The main goal of our paper is to consider the financial and economic justification of the implementation of the first phase of the project of collection, takeover and transport, sorting, and storage of waste tires from the three municipalities in Montenegro. The financial feasibility analysis pointed out the need to organize the second phase of the project and the production of commercially usable and energy efficient products. That phase would lead to the desired commercial effects and will probably ensure the financial sustainability of the project. The economic feasibility analysis of the project included an assessment of the socio-economic benefits from the emission reduction of the first group of pollutants (PM, SOX, NOX, VOC, CO) as a consequence of the waste tires’ destruction, predominantly by combusting them. Unit values of pollution costs by types of gases, adjusted for Montenegro, were defined in the interval from 192 EUR/t for CO to 24,294 EUR/t for PM. We proved that the direct socio-economic benefits of this project are savings in the cost of environmental pollution. The total present value of discounted costs in the observed time period was calculated at the level of EUR 1,620,080, while the total present value of the positive socio-economic effects was estimated at EUR 1,991,180. Dynamic justification indicators suggest that this investment has a satisfactory socio-economic justification, i.e., the economic rate of return is higher than the opportunity cost of capital (ERR = 15.82%), the economic net present value is greater than 0 (ENPV = 371,100 EUR), and the benefit–cost ratio is greater than 1 (B/C ratio = 1.23). Full article
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24 pages, 9980 KiB  
Article
Exploring the Essence of Servo Pump Control
by Guishan Yan, Zhenlin Jin, Tiangui Zhang, Cheng Zhang, Chao Ai and Gexin Chen
Processes 2022, 10(4), 786; https://doi.org/10.3390/pr10040786 - 16 Apr 2022
Cited by 8 | Viewed by 2532
Abstract
The electrohydraulic servo variable speed volume pump control system (hereinafter referred to as ESPCS) is integrated with a permanent magnet synchronous motor (hereinafter referred to as servo motor), a fixed-displacement pump, and a hydraulic cylinder. By controlling the servo motor speed, the output [...] Read more.
The electrohydraulic servo variable speed volume pump control system (hereinafter referred to as ESPCS) is integrated with a permanent magnet synchronous motor (hereinafter referred to as servo motor), a fixed-displacement pump, and a hydraulic cylinder. By controlling the servo motor speed, the output flow of the system can be controlled, as can the displacement, force, and speed of the hydraulic cylinder. Compared with the traditional electro-hydraulic servo valve control system, the ESPCS has the advantages of high power-to-weight ratio, energy saving, and environmental friendliness. However, due to the extremely nonlinear flow output of the ESPCS, further improvement of system control performance is greatly hindered. This paper focuses on the nonlinear characteristics of servo motor, fixed-displacement pump, hydraulic cylinder, and other key components in the system. A compensation method based on nonlinear characteristic mapping is proposed. Compared with the traditional PID control method (pressure control accuracy ± 0.12 MPa), the pressure control accuracy of the system is greatly improved (pressure control accuracy ± 0.037 MPa), which opens up a new way to improve the pressure control accuracy of the ESPCS. Full article
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21 pages, 9622 KiB  
Article
Estimation of Reverse Flow Rate in J-Groove Channel of AJP and SCP Models Using CFD Analysis
by Ujjwal Shrestha and Young-Do Choi
Processes 2022, 10(4), 785; https://doi.org/10.3390/pr10040785 - 16 Apr 2022
Cited by 2 | Viewed by 2013
Abstract
An annular jet pump (AJP) and a screw centrifugal pump (SCP) are special-purpose pumps used for transportation. The flow fields in the AJP and SCP are like those in a diffuser without and with an impeller, respectively. The flow from diffuser inlet to [...] Read more.
An annular jet pump (AJP) and a screw centrifugal pump (SCP) are special-purpose pumps used for transportation. The flow fields in the AJP and SCP are like those in a diffuser without and with an impeller, respectively. The flow from diffuser inlet to outlet takes place via the conversion of kinetic energy to static pressure. J-Groove is installed in the diffuser wall of an AJP and SCP to induce reverse flow from the diffuser outlet to the inlet, which suppresses the cavitation. CFD analysis was carried out to verify the conceptual design and understand the internal flow field of an AJP and SCP with J-Groove. The CFD analysis showed that the J-Groove installation in the AJP and SCP improved suction performance. The reverse flow in the J-Groove is due to the pressure difference between the diffuser outlet and the inlet. The numerical analysis results showed that the reverse flow mechanism is dependent on the flow conditions, cavitation number, and presence of the impeller. In a higher flow rate, the reverse flow rate is higher in the AJP model and lower in the SCP model and vice versa. Finally, CFD analysis concluded that the reverse flow rate in J-Groove improves the suction performance of the AJP and SCP models. Full article
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15 pages, 4691 KiB  
Article
Flash Smelting Settler Design Modifications to Reduce Copper Losses Using Numerical Methods
by Nadir Ali Khan and Ari Jokilaakso
Processes 2022, 10(4), 784; https://doi.org/10.3390/pr10040784 - 16 Apr 2022
Cited by 2 | Viewed by 1858
Abstract
A mathematical modeling approach was used to test different design modifications in a flash smelting settler to reduce the copper losses in slag, which is economically disadvantageous for copper processing using the pyrometallurgical route. The main purpose of this study was to find [...] Read more.
A mathematical modeling approach was used to test different design modifications in a flash smelting settler to reduce the copper losses in slag, which is economically disadvantageous for copper processing using the pyrometallurgical route. The main purpose of this study was to find ways to reduce copper losses in slag by improving the settling and coalescence of copper matte droplets, in particular, the smallest droplet sizes of ≤100 µm. These improvements inside the flash smelting (FS) settler were targeted through different settler design modifications. Three different design schemes were tested using the commercial computational fluid dynamics (CFD) software, Ansys Fluent. These settler design modification schemes included the impact of various baffle types, positioning, the height inside the settler, and settler bottom inclinations. Simulations were carried out with and without coalescence and the results were compared with normal settler design. The results revealed that the settling phenomenon and coalescence efficiency were improved significantly with these design modifications. It was concluded that a single baffle design was optimal for reducing copper losses and increasing coalescence efficiency instead of using multiple baffle arrangements. The top-mounted baffle outperformed the bottom-mounted baffle and inclined settler design. Full article
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10 pages, 404 KiB  
Article
Inventory Model with Stochastic Demand Using Single-Period Inventory Model and Gaussian Process
by Jose Mejia, Liliana Avelar-Sosa, Boris Mederos and Jorge L. García-Alcaraz
Processes 2022, 10(4), 783; https://doi.org/10.3390/pr10040783 - 16 Apr 2022
Viewed by 2403
Abstract
Proper inventory management is vital to achieving sustainability within a supply chain and is also related to a company’s cash flow through the funds represented by the inventory. Therefore, it is necessary to balance excess inventory and insufficient inventory. However, this can be [...] Read more.
Proper inventory management is vital to achieving sustainability within a supply chain and is also related to a company’s cash flow through the funds represented by the inventory. Therefore, it is necessary to balance excess inventory and insufficient inventory. However, this can be difficult to achieve in the presence of stochastic demand because decisions must be made in an uncertain environment and the inventory policy bears risks associated with each decision. This study reports an extension of the single-period model for the inventory problem under uncertain demand. We proposed incorporating a Gaussian stochastic process into the model using the associated posterior distribution of the Gaussian process as a distribution for the demand. This enables the modeling of data from historical inventory demand using the Gaussian process theory, which adapts well to small datasets and provides measurements of the risks associated with the predictions made. Thus, unlike other works that assume that demand follows an autoregressive or Brownian motion model, among others, our approach enables adaptability to different complex forms of demand trends over time. We offer several numerical examples that explore aspects of the proposed approach and compare our results with those achieved using other state-of-the-art methods. Full article
(This article belongs to the Section Process Control and Monitoring)
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11 pages, 9362 KiB  
Article
Simultaneous Achievement of High-Yield Hydrogen and High-Performance Microwave Absorption Materials from Microwave Catalytic Deconstruction of Plastic Waste
by Hui Wang, Bowen Zhang, Pan Luo, Kama Huang and Yanping Zhou
Processes 2022, 10(4), 782; https://doi.org/10.3390/pr10040782 - 16 Apr 2022
Cited by 6 | Viewed by 1993
Abstract
Here, FeAlOx catalytic deconstruction of polyethylene in a domestic microwave oven is reported. With the starting weight ratio of FeAlOx to polyethylene at 1:1, the concentration and yield of H2 reach up to 67.85 vol% and 48.1 mmol g−1 [...] Read more.
Here, FeAlOx catalytic deconstruction of polyethylene in a domestic microwave oven is reported. With the starting weight ratio of FeAlOx to polyethylene at 1:1, the concentration and yield of H2 reach up to 67.85 vol% and 48.1 mmol g−1plastic, respectively. CNTs@Fe3O4/Fe3C/Fe composite, which exhibits excellent microwave absorption properties, is generated simultaneously. The minimum reflection loss (RLmin) of the solid product reaches −54.78 dB at 15 GHz with an effective absorption bandwidth of 4.5 GHz at the thickness of 1.57 mm. Full article
(This article belongs to the Section Materials Processes)
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22 pages, 619 KiB  
Article
Stochastic Review Inventory Systems with Deteriorating Items; A Steady-State Non-Linear Approach
by Adel F. Alrasheedi, Khalid A. Alnowibet and Ibtisam T. Alotaibi
Processes 2022, 10(4), 781; https://doi.org/10.3390/pr10040781 - 16 Apr 2022
Cited by 1 | Viewed by 1634
Abstract
The primary goal of business organization is optimally maximizing their productivity and profit whilst reducing the cost resulting from lost sales and services given to their customers, which can be achieved by exceeding the balance between the demand and supply. Analyzing real-world situations, [...] Read more.
The primary goal of business organization is optimally maximizing their productivity and profit whilst reducing the cost resulting from lost sales and services given to their customers, which can be achieved by exceeding the balance between the demand and supply. Analyzing real-world situations, including integrated queuing-inventory systems, such as M/M/1-systems and M/M/1/-systems, can help business organizations reach this goal. This research analyzes integrated queuing-inventory systems with lost sales validated under a deterministic and uniformly distributed order size scheme under continuous review. The limited integrated inventory-queuing M/M/1/N-1-system was chosen as subject of our interest due to its closeness to reality. Thus, this system with exponentially distributed deteriorating products and random planning time with lost sales was simulated. This research aimed to analyze customers’ sanctification by studying the addition of the deterioration parameter γ to the model under consideration. The proposed model’s demand was based on Poisson, wherein service times and lead times are exponentially distributed. We also examined M/M/1/ and M/M/1/N-1-systems investigated by Shwarz et al. using the proposed method to solve the linear system of equations obtained from the steady-state system balance equations results obtained are compared to those obtained from simulating the Schwarz approach. The analyzed model was tested for different values of Q, demand rate λ, and γ. The obtained results showed a strong dependency between γ, Q, and λ, providing the needed information for decision-makers to reach their goals depending on the performance measure of interest. Full article
(This article belongs to the Special Issue Advances in Nonlinear and Stochastic System Control)
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8 pages, 2703 KiB  
Article
Evaluation of Porcine and Aspergillus oryzae α-Amylases as Possible Model for the Human Enzyme
by Mauro Marengo, Davide Pezzilli, Eleonora Gianquinto, Alex Fissore, Simonetta Oliaro-Bosso, Barbara Sgorbini, Francesca Spyrakis and Salvatore Adinolfi
Processes 2022, 10(4), 780; https://doi.org/10.3390/pr10040780 - 15 Apr 2022
Cited by 7 | Viewed by 2632
Abstract
α-amylases are ubiquitous enzymes belonging to the glycosyl hydrolase (GH13) family, whose members share a high degree of sequence identity, even between distant organisms. To understand the determinants of catalytic activity of α-amylases throughout evolution, and to investigate the use of homologous enzymes [...] Read more.
α-amylases are ubiquitous enzymes belonging to the glycosyl hydrolase (GH13) family, whose members share a high degree of sequence identity, even between distant organisms. To understand the determinants of catalytic activity of α-amylases throughout evolution, and to investigate the use of homologous enzymes as a model for the human one, we compared human salivary α-amylase, Aspergillus oryzae α-amylase and pancreatic porcine α-amylase, using a combination of in vitro and in silico approaches. Enzyme sequences were aligned, and structures superposed, whereas kinetics were spectroscopically studied by using commercial synthetic substrates. These three enzymes show strikingly different activities, specifically mediated by different ions, despite relevant structural homology. Our study confirms that the function of α-amylases throughout evolution has considerably diverged, although key structural determinants, such as the catalytic triad and the calcium-binding pocket, have been retained. These functional differences need to be carefully considered when α-amylases, from different organisms, are used as a model for the human enzymes. In this frame, particular focus is needed for the setup of proper experimental conditions. Full article
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11 pages, 1482 KiB  
Article
Di- and Mono-Rhamnolipids Produced by the Pseudomonas putida PP021 Isolate Significantly Enhance the Degree of Recovery of Heavy Oil from the Romashkino Oil Field (Tatarstan, Russia)
by Liliya Biktasheva, Alexander Gordeev, Svetlana Selivanovskaya and Polina Galitskaya
Processes 2022, 10(4), 779; https://doi.org/10.3390/pr10040779 - 15 Apr 2022
Cited by 9 | Viewed by 2336
Abstract
Around the globe, only 30–50% of the amount of oil estimated to be in reservoirs (“original oil in place”) can be obtained using primary and secondary oil recovery methods. Enhanced oil recovery methods are required in the oil processing industry, and the use [...] Read more.
Around the globe, only 30–50% of the amount of oil estimated to be in reservoirs (“original oil in place”) can be obtained using primary and secondary oil recovery methods. Enhanced oil recovery methods are required in the oil processing industry, and the use of microbially produced amphiphilic molecules (biosurfactants) is considered a promising efficient and environmentally friendly method. In the present study, biosurfactants produced by the Pseudomonas putida PP021 isolate were extracted and characterized, and their potential to enhance oil recovery was demonstrated. It was found that the cell-free biosurfactant-containing supernatant decreased the air–water interface tension from 74 to 28 mN m−1. Using TLC and FTIR methods, the biosurfactants produced by the isolate were classified as mono- and di-rhamnolipid mixtures. In the isolates’ genome, the genes rhlB and rhlC, encoding enzymes involved in the synthesis of mono- and di-rhamnolipids, respectively, were revealed. Both genes were expressed when the strain was cultivated on glycerol nitrate medium. As follows from the sand-packed column and core flooding simulations, biosurfactants produced by P. putida PP021 significantly enhance the degree of recovery, resulting in additional 27% and 21%, respectively. Full article
(This article belongs to the Topic Chemical and Biochemical Processes for Energy Sources)
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14 pages, 4379 KiB  
Article
Effect of Ternary Deep Eutectic Solvents on Bagasse Cellulose and Lignin Structure in Low-Temperature Pretreatment
by Yuanxing Yang, Lihong Zhao, Junli Ren and Beihai He
Processes 2022, 10(4), 778; https://doi.org/10.3390/pr10040778 - 15 Apr 2022
Cited by 11 | Viewed by 3280
Abstract
Deep eutectic solvents (DESs) have been used for the pretreatment of lignocellulose and showed selective dissolution for different lignocellulosic components. In this study, six new ternary DESs were synthesized on the basis of anhydrous oxalic acid DES by adding alcohol, acid, and deionized [...] Read more.
Deep eutectic solvents (DESs) have been used for the pretreatment of lignocellulose and showed selective dissolution for different lignocellulosic components. In this study, six new ternary DESs were synthesized on the basis of anhydrous oxalic acid DES by adding alcohol, acid, and deionized water, respectively, including choline chloride/anhydrous oxalic acid/ethylene glycol (ChCl-OA-EG), choline chloride/anhydrous oxalic acid/glycerol (ChCl-OA-G), choline chloride/anhydrous oxalic acid/lactic acid (ChCl-OA-LA), choline chloride/anhydrous oxalic acid/malonic acid (ChCl-OA-MA), choline chloride/anhydrous oxalic acid/10% H2O (v/v) (ChCl-OA + 10% H2O), and choline chloride/anhydrous oxalic acid/20% H2O (v/v) (ChCl-OA + 20% H2O). The lignin in bagasse was extracted and separated with these ternary DESs, and Fourier Transform Infrared (FTIR), Scanning electron microscope (SEM), X-ray diffraction (XRD), Two-dimensional Heteronuclear Single Quantum Coherence (2D HSQC), and Thermogravimetric analysis (TG) were used to characterize the molecular structures of lignin and cellulose. The results showed that under the mild reaction condition of cooking at 90 °C for 4 h, all six ternary DESs effectively dissolved hemicellulose in bagasse, the DES ChCl-OA-MA prepared with malonic acid significantly increased the removal of lignin (71.64%) by breaking the β-O-4′ ether bond of lignin molecules, and the crystallinity of cellulose was also significantly improved (67.65%). Full article
(This article belongs to the Special Issue Lignocellulose Pretreatment and Utilization)
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14 pages, 2462 KiB  
Article
Investigating the Enhancement in Biogas Production by Hydrothermal Carbonization of Organic Solid Waste and Digestate in an Inter-Stage Treatment Configuration
by Roberta Ferrentino, Michela Langone, Davide Mattioli, Luca Fiori and Gianni Andreottola
Processes 2022, 10(4), 777; https://doi.org/10.3390/pr10040777 - 15 Apr 2022
Cited by 4 | Viewed by 2110
Abstract
In recent years, sewage sludge (SS) and bio-waste management have attracted increasing environmental attention. In this study, hydrothermal carbonization (HTC) technology is investigated in the framework of a co-treatment of sewage sludge digestate (SSD) and an organic fraction of municipal solid waste (OW). [...] Read more.
In recent years, sewage sludge (SS) and bio-waste management have attracted increasing environmental attention. In this study, hydrothermal carbonization (HTC) technology is investigated in the framework of a co-treatment of sewage sludge digestate (SSD) and an organic fraction of municipal solid waste (OW). The proposed configuration integrates HTC with anaerobic digestion (AD) in an inter-stage configuration (AD1 + HTC + AD2). The effects of different percentages of OW added to SSD in the HTC treatment are evaluated in terms of characteristics and methane yield of the produced HTC liquor (HTCL) and HTC slurry (i.e., the mixture hydrochar-HTCL), as well as dewaterability of the HTC slurry. Results show that, with the increase in the percentage of OW in the OW-SSD mixture fed to the HTC process, production of biogas and biomethane of both HTC slurry and HTCL increases. The highest biogas production is achieved when a mixture consisting of half SSD and half OW is used, reaching 160 ± 10 and 240 ± 15 mL biogas g−1 CODadded, respectively, for HTCL and HTC slurry. Furthermore, sludge dewaterability is significantly improved by the combined AD1-HTC-AD2 process. Finally, an energy assessment allows estimating that the co-treatment of OW with SSD in HTC can cover up to 100% of the energy consumption of the system. Full article
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21 pages, 4391 KiB  
Article
Convective Heat and Mass Transfer in Third-Grade Fluid with Darcy–Forchheimer Relation in the Presence of Thermal-Diffusion and Diffusion-Thermo Effects over an Exponentially Inclined Stretching Sheet Surrounded by a Porous Medium: A CFD Study
by Amir Abbas, Ramsha Shafqat, Mdi Begum Jeelani and Nadiyah Hussain Alharthi
Processes 2022, 10(4), 776; https://doi.org/10.3390/pr10040776 - 15 Apr 2022
Cited by 30 | Viewed by 2367
Abstract
The current study aims to investigate the thermal-diffusion and diffusion-thermo effects on heat and mass transfer in third-grade fluid with Darcy–Forchheimer relation impact over an exponentially inclined stretching sheet embedded in a porous medium. The proposed mechanism in terms non-linear and coupled partial [...] Read more.
The current study aims to investigate the thermal-diffusion and diffusion-thermo effects on heat and mass transfer in third-grade fluid with Darcy–Forchheimer relation impact over an exponentially inclined stretching sheet embedded in a porous medium. The proposed mechanism in terms non-linear and coupled partial differential equations is reduced to set of ordinary differential equations by employing an appropriate similarity variable formulation. The reduced form of equations is solved by using the MATLAB built-in numerical solver bvp4c. The numerical results for unknown physical properties such as velocity profile, temperature field, and mass concentration along with their gradients such as the skin friction, the rate of heat transfer, and the rate of mass transfer at angle of inclination α=π/6 are obtained under the impact of material parameters that appear in the flow model. The solutions are displayed in forms of graphs as well as tables and are discussed with physical reasoning. From the demonstration of the graphical results, it is inferred that thermal-diffusion parameter Sr velocity, temperature, and concentration profiles are augmented. For the increasing magnitude of the diffusion-thermo parameter Df the fluid velocity and fluid temperature rise but the opposite trend in mass concentration is noted. The current results are compared with the available results in the existing literature, and there is good agreement between them that shows the validation of the present study. Full article
(This article belongs to the Special Issue Advances in CFD Analysis of Convective Heat Transfer)
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12 pages, 790 KiB  
Communication
The Regression Rate-Based Preliminary Engineering Design of Hybrid Rocket Combustion System
by Ştefan Predoi, Ştefan Grigorean and Gheorghe Dumitraşcu
Processes 2022, 10(4), 775; https://doi.org/10.3390/pr10040775 - 15 Apr 2022
Cited by 2 | Viewed by 2625
Abstract
The paper presents a useful engineering model for the design of preliminary hybrid rocket engines. This model involves the experimentally obtained equation regarding the speed of the burning interface between solid fuel and gaseous phase, called the regression rate. This regression rate characterizes [...] Read more.
The paper presents a useful engineering model for the design of preliminary hybrid rocket engines. This model involves the experimentally obtained equation regarding the speed of the burning interface between solid fuel and gaseous phase, called the regression rate. This regression rate characterizes the mass rate of the burning fuel and additionally the mass rate of the oxidizer through the imposed ratio of these mass rates during combustion. The preliminary design is applied to combustion using pure HTPB and gaseous oxygen and was developed for three cases, constant regression rate, constant oxygen mass flow rate and constant O/F (ratio of mass rates of oxygen and of fuel). The design evaluates the initial fuel port geometry, the initial mass of fuel and oxygen, the combustion time, the thrust at sea level, and the time-dependent functions of regression rate, of fuel and oxygen mass rates, and of thrust. It was assumed that the regression rate formula applies at any time of combustion. These evaluations can also be applied for other fuel/oxygen couples by knowing the correct formula for the regression rate. Full article
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20 pages, 5490 KiB  
Article
Transient Stability Analysis of Direct Drive Wind Turbine in DC-Link Voltage Control Timescale during Grid Fault
by Qi Hu, Yiyong Xiong, Chenruiyang Liu, Guangyu Wang and Yanhong Ma
Processes 2022, 10(4), 774; https://doi.org/10.3390/pr10040774 - 15 Apr 2022
Cited by 4 | Viewed by 1644
Abstract
Transient stability during grid fault is experienced differently in modern power systems, especially in wind-turbine-dominated power systems. In this paper, transient behavior and stability issues of a direct drive wind turbine during fault recovery in DC-link voltage control timescale are studied. First, the [...] Read more.
Transient stability during grid fault is experienced differently in modern power systems, especially in wind-turbine-dominated power systems. In this paper, transient behavior and stability issues of a direct drive wind turbine during fault recovery in DC-link voltage control timescale are studied. First, the motion equation model that depicts the phase and amplitude dynamics of internal voltage driven by unbalanced active and reactive power is developed to physically depict transient characteristics of the direct drive wind turbine itself. Considering transient switch control induced by active power climbing, the two-stage model is employed. Based on the motion equation model, transient behavior during fault recovery in a single machine infinite bus system is studied, and the analysis is also divided into two stages: during and after active power climbing. During active power climbing, a novel approximate analytical expression is proposed to clearly reveal the frequency dynamics of the direct drive wind turbine, which is identified as approximate monotonicity at excitation of active power climbing. After active power climbing, large-signal oscillation behavior is concerned. A novel analysis idea combining time-frequency analysis based on Hilbert transform and high order modes is employed to investigate and reveal the nonlinear oscillation, which is characterized by time-varying oscillation frequency and amplitude attenuation ratio. It is found that the nonlinear oscillation and even stability are related closely to the final point during active power climbing. With a large active power climbing rate, the nonlinear oscillation may lose stability. Simulated results based on MATLAB® are also presented to verify the theoretical analysis. Full article
(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)
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14 pages, 9525 KiB  
Article
Numerical Simulation of Influencing Factors of Hydraulic Fracture Network Development in Reservoirs with Pre-Existing Fractures
by Kai Zhao, Runsen Li, Haoran Lei, Wei Gao, Zhenwei Zhang, Xiaoyun Wang and Le Qu
Processes 2022, 10(4), 773; https://doi.org/10.3390/pr10040773 - 15 Apr 2022
Cited by 5 | Viewed by 1689
Abstract
The intersection behavior of hydraulic fractures and single natural fractures has been studied in detail; however, in fractured reservoirs, natural fractures are numerous and interlaced and the intersection of hydraulic fractures and multiple natural fractures occurs during the fracturing process. This intersection behavior [...] Read more.
The intersection behavior of hydraulic fractures and single natural fractures has been studied in detail; however, in fractured reservoirs, natural fractures are numerous and interlaced and the intersection of hydraulic fractures and multiple natural fractures occurs during the fracturing process. This intersection behavior is more complex and there is a lack of research on this topic at present. In this study, a numerical simulation model of the interaction between hydraulic fractures and a series of natural fractures was established, the main factors that affect the formation scale of a fracture network during the hydraulic fracturing of a fractured reservoir were studied using the numerical simulation method, and the parameters were also studied. The results showed that the natural fracture trend, in situ stress difference, and injection flow rate have an impact on the scale of a fracture network. The larger the in situ stress difference, the smaller the scale of the fracture network, which gradually changes from multiple clusters of fractures to single fractures. The larger the injection flow rate, the larger the scale of the fracture network. In the uniform stress field, the direction of a natural fracture is closer to the direction of principal stress, so the lower the fracture extension pressure, the smaller the scale of the network. On the contrary, the farther away from the principal stress direction, the lower the fracture extension pressure and the higher the extension pressure, the larger the scale of the fracture network. Full article
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10 pages, 233 KiB  
Editorial
Expanding the Horizons of Manufacturing, towards Wide Integration, Smart System, and Tools
by Luis Puigjaner, Antonio Espuña, Edrisi Muñoz and Elisabet Capón-García
Processes 2022, 10(4), 772; https://doi.org/10.3390/pr10040772 - 14 Apr 2022
Cited by 1 | Viewed by 1297
Abstract
This research topic aims at enterprise-wide modeling and optimization (EWMO) through the development and application of integrated modeling, simulation and optimization methodologies, and computer-aided tools for reliable and sustainable improvement opportunities within the entire manufacturing network (raw materials, production plants, distribution, retailers, and [...] Read more.
This research topic aims at enterprise-wide modeling and optimization (EWMO) through the development and application of integrated modeling, simulation and optimization methodologies, and computer-aided tools for reliable and sustainable improvement opportunities within the entire manufacturing network (raw materials, production plants, distribution, retailers, and customers) and its components [...] Full article
16 pages, 36263 KiB  
Article
Effect of the Vortex Finder and Feed Parameters on the Short-Circuit Flow and Separation Performance of a Hydrocyclone
by Tenglong Su and Yifei Zhang
Processes 2022, 10(4), 771; https://doi.org/10.3390/pr10040771 - 14 Apr 2022
Cited by 8 | Viewed by 4097
Abstract
The short-circuit flow, which is discharged from the vortex finder without separation, seriously affects the processing efficiency of the hydrocyclone. In this paper, the experimental test and numerical simulation methods are used to study the effect of the vortex finder and feed parameters [...] Read more.
The short-circuit flow, which is discharged from the vortex finder without separation, seriously affects the processing efficiency of the hydrocyclone. In this paper, the experimental test and numerical simulation methods are used to study the effect of the vortex finder and feed parameters on the short-circuit flow and separation performance. The Reynolds Stress method (RSM), Volume of Fluid (VOF), and Mixture model were adopted to predict the separation process in the hydrocyclone. The simulation results are analyzed in terms of the short-circuit flow rate, the ratio of the short-circuit flow rate to the inlet flow rate (hereafter this paper will be abbreviated as “its ratio”) and the separation efficiency. The results indicate that the smaller vortex finder diameter, thick-walled vortex finder, and moderate vortex finder length are conducive to inhibiting the short-circuit flow and decreasing the cut size (d50). A faster inlet velocity and higher feed concentration could increase the short-circuit flow but reduce its ratio. The relatively faster inlet velocity and lower feed concentration could decrease the d50 and improve the separation efficiency. Full article
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19 pages, 1811 KiB  
Article
Long-Term Person Re-Identification Based on Appearance and Gait Feature Fusion under Covariate Changes
by Xiaoyan Lu, Xinde Li, Weijie Sheng and Shuzhi Sam Ge
Processes 2022, 10(4), 770; https://doi.org/10.3390/pr10040770 - 14 Apr 2022
Cited by 6 | Viewed by 2245
Abstract
Person re-identification(Re-ID) technology has been a research hotspot in intelligent video surveillance, which accurately retrieves specific pedestrians from massive video data. Most research focuses on the short-term scenarios of person Re-ID to deal with general problems, such as occlusion, illumination change, and view [...] Read more.
Person re-identification(Re-ID) technology has been a research hotspot in intelligent video surveillance, which accurately retrieves specific pedestrians from massive video data. Most research focuses on the short-term scenarios of person Re-ID to deal with general problems, such as occlusion, illumination change, and view variance. The appearance change or similar appearance problem in the long-term scenarios has has not been the focus of past research. This paper proposes a novel Re-ID framework consisting of a two-branch model to fuse the appearance and gait feature to overcome covariate changes. Firstly, we extract the appearance features from a video sequence by ResNet50 and leverage average pooling to aggregate the features. Secondly, we design an improved gait representation to obtain a person’s motion information and exclude the effects of external covariates. Specifically, we accumulate the difference between silhouettes to form an active energy image (AEI) and then mask the mid-body part in the image with the Improved-Sobel-Masking operator to extract the final gait representation called ISMAEI. Thirdly, we combine appearance features with gait features to generate discriminative and robust fused features. Finally, the Euclidean norm is adopted to calculate the distance between probe and gallery samples for person Re-ID. The proposed method is evaluated on the CASIA Gait Database B and TUM-GAID datasets. Compared with state-of-the-art methods, experimental results demonstrate that it can perform better in both Rank-1 and mAP. Full article
(This article belongs to the Section Advanced Digital and Other Processes)
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18 pages, 457 KiB  
Article
Event-Triggered Filtering for Delayed Markov Jump Nonlinear Systems with Unknown Probabilities
by Huiying Chen, Renwei Liu, Weifeng Xia and Zuxin Li
Processes 2022, 10(4), 769; https://doi.org/10.3390/pr10040769 - 14 Apr 2022
Cited by 3 | Viewed by 1401
Abstract
This paper focuses on the problem of event-triggered H asynchronous filtering for Markov jump nonlinear systems with varying delay and unknown probabilities. An event-triggered scheduling scheme is adopted to decrease the transmission rate of measured outputs. The devised filter is mode dependent [...] Read more.
This paper focuses on the problem of event-triggered H asynchronous filtering for Markov jump nonlinear systems with varying delay and unknown probabilities. An event-triggered scheduling scheme is adopted to decrease the transmission rate of measured outputs. The devised filter is mode dependent and asynchronous with the original system, which is represented by a hidden Markov model (HMM). Both the probability information involved in the original system and the filter are assumed to be only partly available. Under this framework, via employing the Lyapunov–Krasovskii functional and matrix inequality transformation techniques, a sufficient condition is given and the filter is further devised to ensure that the resulting filtering error dynamic system is stochastically stable with a desired H disturbance attenuation performance. Lastly, the validity of the presented filter design scheme is verified through a numerical example. Full article
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