| 1. |
- Carlsson, Leo, et al.
(författare)
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A Proposed Methodology to Evaluate Machine Learning Models at Near-Upper-Bound Predictive Performance—Some Practical Cases from the Steel Industry
- 2023
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Ingår i: Processes. - : MDPI AG. - 2227-9717. ; 11:12
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Tidskriftsartikel (refereegranskat)abstract
- The present work aims to answer three essential research questions (RQs) that have previously not been explicitly dealt with in the field of applied machine learning (ML) in steel process engineering. RQ1: How many training data points are needed to create a model with near-upper-bound predictive performance on test data? RQ2: What is the near-upper-bound predictive performance on test data? RQ3: For how long can a model be used before its predictive performance starts to decrease? A methodology to answer these RQs is proposed. The methodology uses a developed sampling algorithm that samples numerous unique training and test datasets. Each sample was used to create one ML model. The predictive performance of the resulting ML models was analyzed using common statistical tools. The proposed methodology was applied to four disparate datasets from the steel industry in order to externally validate the experimental results. It was shown that the proposed methodology can be used to answer each of the three RQs. Furthermore, a few findings that contradict established ML knowledge were also found during the application of the proposed methodology.
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| 2. |
- Chawade, Aakash
(författare)
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Biogas Upgradation by CO2 Sequestration and Simultaneous Production of Acetic Acid by Novel Isolated Bacteria
- 2023
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Ingår i: Processes. - 2227-9717. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Anaerobic digestion produces biogas, which is a proven bioprocess for generating energy, recovering nutrients, and reusing waste materials. Generally, the biogas generated contains methane (CH4) and carbon dioxide (CO2) in a 3:2 ratio, which limits the usage of the biogas to only cooking gas. To further enhance the application of biogas to vehicular fuel and natural gas grids, CO2 must be removed for an enhanced calorific value. This study seeks to lower greenhouse gas emissions by sequestering carbon dioxide from biogas. CO2 sequestration by microorganisms to upgrade the biogas and simultaneously convert the CO2 into acetic acid is a less explored area of research. Therefore, this research focuses mainly on the analysis of CO2 consumption % and acetic acid yield by novel isolated bacteria from fruit waste and mixed consortia obtained from cow dung and digested samples. The research finding states that there was a 32% increase in methane yield shown by isolated strain A1, i.e., CH4% was increased from 60% to 90%, whereas only an 11% increase was shown by consortia, which was an increase from 60% to 80%. The highest biogas upgradation was shown by the A1 strain at 30 degrees C incubation temperature and pH 8. The A1 strain demonstrated the highest recorded yield of acetic acid, reaching a concentration of 2215 mg/L at pH 8. A pH range of 7-8 was found to be the best-suited pH, and a mesophilic temperature was optimum for CO2 consumption and acetic acid production. The major objective is to create an effective method for improving biogas so that it is acceptable for different energy applications by lowering the carbon dioxide content and raising the methane content. This development signifies a significant advancement in the enhancement of biogas upgradation, as well as the concurrent generation of value-added goods, thereby establishing a sustainable platform technology.
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| 3. |
- Dai, Fei, et al.
(författare)
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Recent Progress on Hydrogen-Rich Syngas Production from Coal Gasification
- 2023
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Ingår i: Processes. - : MDPI. - 2227-9717. ; 11:6
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Tidskriftsartikel (refereegranskat)abstract
- Coal gasification is recognized as the core technology of clean coal utilization that exhibits significant advantages in hydrogen-rich syngas production and CO2 emission reduction. This review briefly discusses the recent research progress on various coal gasification techniques, including conventional coal gasification (fixed bed, fluidized bed, and entrained bed gasification) and relatively new coal gasification (supercritical water gasification, plasma gasification, chemical-looping gasification, and decoupling gasification) in terms of their gasifiers, process parameters (such as coal type, temperature, pressure, gasification agents, catalysts, etc.), advantages, and challenges. The capacity and potential of hydrogen production through different coal gasification technologies are also systematically analyzed. In this regard, the decoupling gasification technology based on pyrolysis, coal char–CO2 gasification, and CO shift reaction shows remarkable features in improving comprehensive utilization of coal, low-energy capture and conversion of CO2, as well as efficient hydrogen production. As the key unit of decoupling gasification, this work also reviews recent research advances (2019–2023) in coal char–CO2 gasification, the influence of different factors such as coal type, gasification agent composition, temperature, pressure, particle size, and catalyst on the char–CO2 gasification performance are studied, and its reaction kinetics are also outlined. This review serves as guidance for further excavating the potential of gasification technology in promoting clean fuel production and mitigating greenhouse gas emissions.
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| 4. |
- Deliiski, Nencho, et al.
(författare)
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Computing the Thermal Efficiency of Autoclaves during Steaming of Frozen Prisms for Veneer Production at Changing Operational Conditions
- 2023
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Ingår i: Processes. - : MDPI. - 2227-9717. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- A methodology for the computation of the thermal energy efficiency of modes for the heat treatment of frozen wooden prisms in an autoclave with saturated water vapor at changing operational conditions has been proposed. The methodology includes computer simulations with two own-coupled unsteady models: one to calculate the 2D temperature distribution in the cross-section of prismatic wood materials during their heat treatment, and the second to determine the heat balance of industrial autoclaves for such wood treatment. Simulations were carried out in order to determine the duration, energy consumption, and thermal efficiency of different modes, caused by changed operational conditions, for the autoclave steaming of frozen beech prisms with industrial parameters in the absence and presence of dispatcher intervention. The influence of nine combinations between the time of dispatcher intervention and the degree of reduction of the constant maximum temperature from the 130 °C of the basic mode on the thermal efficiency of the autoclave was investigated. The results show that all studied dispatching interventions cause an increase in both the duration and the thermal efficiency of the modes. This efficiency in the modes at changing operational conditions has values between 68.7% and 74.6%, while the efficiency in the basic steaming mode is equal to 68.0%.
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| 5. |
- Ghodke, Praveen Kumar, et al.
(författare)
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Experimental Investigation on Pyrolysis of Domestic Plastic Wastes for Fuel Grade Hydrocarbons
- 2023
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Ingår i: Processes. - : MDPI. - 2227-9717. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Plastics usage is rising daily because of increased population, modernization, and industrialization, which produces a lot of plastic garbage. Due to their various chemical structures, long chain polymeric compositions, and thermal/decomposition behavior, it is challenging to recycle these plastic wastes into hydrocarbon fuels. In the current work, domestic plastic waste was pyrolyzed at 473 to 973 K in a fixed bed reactor and compared with the three virgin plastics LDPE (low-density polyethylene), HDPE (high-density polyethylene), and PP (polypropylene), as well as a mixture of the three (virgin mixed plastics). The pyrolysis results showed that maximum liquid hydrocarbons obtained from HDPE, LDPE, PP, mixed plastic, and domestic waste were 64.6 wt.%, 62.2 wt.%, 63.1 wt.%, 68.6 wt.%, and 64.6 wt.% at 773 K, respectively. The composition of liquid fuels was characterized using FTIR and GC-MS, which showed a wide spectrum of hydrocarbons in the C8–C20 range. Furthermore, liquid fuel characteristics such as density, viscosity, fire and flash point, pour point, and calorific value were examined using ASTM standards, and the results were found to be satisfactory. This study provides an innovative method for recycling waste plastics into economical hydrocarbon fuel for use in transportation.
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| 6. |
- Hosseinzadeh Dadash, Amirhossein, 1986-, et al.
(författare)
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Optimal Degradation-Aware Control Using Process-Controlled Sparse Bayesian Learning
- 2023
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Ingår i: Processes. - : MDPI. - 2227-9717. ; 11:11
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Tidskriftsartikel (refereegranskat)abstract
- Efficient production planning hinges on reducing costs and maintaining output quality, with machine degradation management as a key factor. The traditional approaches to control this degradation face two main challenges: high costs associated with physical modeling and a lack of physical interpretability in machine learning methods. Addressing these issues, our study presents an innovative solution focused on controlling the degradation, a common cause of machine failure. We propose a method that integrates machine degradation as a virtual state within the system model, utilizing relevance vector machine-based identification designed in a way that offers physical interpretability. This integration maximizes the machine’s operational lifespan. Our approach merges a physical machine model with a physically interpretable data-driven degradation model, effectively tackling the challenges in physical degradation modeling and accessibility to the system disturbance model. By embedding degradation into the system’s state-space model, we simplify implementation and address stability issues. The results demonstrate that our method effectively controls degradation and significantly increases the machine’s mean time to failure. This represents a significant advancement in production planning, offering a cost-effective and interpretable method for managing machine degradation.
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| 7. |
- Jabeen, Mehreen, et al.
(författare)
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Exploring the Antioxidant and Anti-Inflammatory Potential of Wilckia maritima: In Vitro and In Silico Investigations
- 2023
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Ingår i: Processes. - : MDPI. - 2227-9717. ; 11:5
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Tidskriftsartikel (refereegranskat)abstract
- This research aimed to assess the anti-inflammatory and antioxidant potential of methanol extract of Wilckia maritima, a plant belonging to the family Brassicaceae, which is enriched with natural antioxidants. Qualitative phytochemical studies showed the presence of numerous compounds including glycosides, phenols, triterpenoids, and GC-MS studies revealed the presence of 35 bioactive components, including n-hexadecanoic acid (26.96%), 9,12,15 octadecatrienoic acid (cis) (25.52%), 3,5 di-hydroxy-6-methyl 2,3-di-hydro-4-pyran 4-one (14.35%), and 3-tertiary butyl-4-hydroxy-anisol (11.68%) as major components, which are thought to be responsible for anti-inflammatory and antioxidant potentials of methanol extract of W. maritima., flavonoids, steroids, tannins, and saponins. The antioxidant potential of the extract was determined by performing various assays, including DPPH free radical scavenging, ferrous reducing, and hydrogen peroxide assays, which showed significant percentage inhibition (83.55 +/- 0.89, 79.40 +/- 1.17, and 81.26 +/- 0.36%, respectively) as compared to ascorbic acid (standard). The extract also exhibited significant anti-inflammatory activity with percentage inhibition 65.66 +/- 0.42% compared to standard ibuprofen, which showed 73.20 +/- 0.21% inhibition. In vivo analysis further confirmed this anti-inflammatory potential of the extract, showing a 75.55 +/- 0.11% reduction in edema at 300 mg/kg as compared with standard diclofenac sodium 70.27 +/- 0.012%. Moreover, in silico investigations revealed that the phytocompounds in W. maritima exhibited excellent antioxidant and anti-inflammatory characteristics, which could provide novel biological molecules for target receptors. Overall, our findings suggest that W. maritima can be utilized as a potential resource of natural compounds with antioxidants and anti-inflammatory potential, with promising therapeutic effect in relieving various ailments related to inflammatory response.
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| 8. |
- Jin, Yanghao, et al.
(författare)
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From Waste Biomass to Hard Carbon Anodes : Predicting the Relationship between Biomass Processing Parameters and Performance of Hard Carbons in Sodium-Ion Batteries
- 2023
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Ingår i: Processes. - : MDPI AG. - 2227-9717. ; 11:3
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Forskningsöversikt (refereegranskat)abstract
- Sodium-ion batteries (SIBs) serve as the most promising next-generation commercial batteries besides lithium-ion batteries (LIBs). Hard carbon (HC) from renewable biomass resources is the most commonly used anode material in SIBs. In this contribution, we present a review of the latest progress in the conversion of waste biomass to HC materials, and highlight their application in SIBs. Specifically, the following topics are discussed in the review: (1) the mechanism of sodium-ion storage in HC, (2) the HC precursor's sources, (3) the processing methods and conditions of the HCs production, (4) the impact of the biomass types and carbonization temperature on the carbon structure, and (5) the effect of various carbon structures on electrochemical performance. Data from various publications have been analyzed to uncover the relationship between the processing conditions of biomass and the resulting structure of the final HC product, as well as its electrochemical performance. Our results indicate the existence of an ideal temperature range (around 1200 to 1400 degrees C) that enhances the formation of graphitic domains in the final HC anode and reduces the formation of open pores from the biomass precursor. This results in HC anodes with high storage capacity (>300 mAh/g) and high initial coulombic efficiency (ICE) (>80%).
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| 9. |
- Micolucci, Federico, 1984, et al.
(författare)
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Candidatus Scalindua, a Biological Solution to Treat Saline Recirculating Aquaculture System Wastewater
- 2023
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Ingår i: Processes. - : MDPI AG. - 2227-9717. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- Recirculating aquaculture systems (RAS) are promising candidates for the sustainable development of the aquaculture industry. A current limitation of RAS is the production and potential accumulation of nitrogenous wastes, ammonium (NH4+), nitrite (NO2-) and nitrate (NO3-), which could affect fish health and welfare. In a previous experiment, we have demonstrated that the marine anammox bacteria Candidatus Scalindua was a promising candidate to treat the wastewater (WW) of marine, cold-water RAS. However, the activity of the bacteria was negatively impacted after a direct exposure to RAS WW. In the current study, we have further investigated the potential of Ca. Scalindua to treat marine RAS WW in a three-phase experiment. In the first phase (control, 83 days), Ca. Scalindua was fed a synthetic feed, enriched in NH4+, NO2- and trace element (TE) mix. Removal rates of 98.9% and 99.6% for NH4+ and NO2-, respectively, were achieved. In the second phase (116 days), we gradually increased the exposure of Ca. Scalindua to nitrogen-enriched RAS WW over a period of about 80 days. In the last phase (79 days), we investigated the needs of TE supplementation for the Ca. Scalindua after they were fully acclimated to 100% RAS WW. Our results show that the gradual exposure of Ca. Scalindua resulted in a successful acclimation to 100% RAS WW, with maintained high removal rates of both NH4+ and NO2- throughout the experiment. Despite a slight decrease in relative abundance (from 21.4% to 16.7%), Ca. Scalindua remained the dominant species in the granules throughout the whole experiment. We conclude that Ca. Scalindua can be successfully used to treat marine RAS WW, without the addition of TE, once given enough time to acclimate to its new substrate. Future studies need to determine the specific needs for optimal RAS WW treatment by Ca. Scalindua at pilot scale.
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| 10. |
- Ribeiro, Luis, et al.
(författare)
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A Software Toolbox for Realistic Dataset Generation for Testing Online and Offline 3D Bin Packing Algorithms
- 2023
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Ingår i: Processes. - : MDPI. - 2227-9717. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- Packing products into a pallet or other medium is an unavoidable activity for producing companies. In many cases, packing is based on operator experience and training using packing patterns that have worked before. Automated packing, on the other hand, requires a systematic procedure for devising packing solutions. In the scientific literature, this problem is known as 3D bin packing (3DBP) and many authors have proposed exact and heuristic solutions for many variations of the problem. There is, however, a lack of datasets that can be used to test and validate such solutions. Many of the available datasets use randomly generated products with extremely limited connection to real practice. Furthermore, they contain a reduced number of product configurations and ignore that packing relates to customers orders, which have specific relative mixes of products. This paper proposes a software toolbox for generating arbitrarily large datasets for 3DBPP based on real industry data. The toolbox was developed in connection with the analysis of a real dataset from the food and beverages sector, which enabled the creation of several synthetic datasets. The toolbox and the synthetic datasets are publicly available and can be used to generate additional data for testing and validating 3DBP solutions. The industry is increasingly becoming data dependent and driven. The ability to generate good quality synthetic data to support the development of solutions to real industry problems is of extreme importance. This work is a step in that direction in a domain where open data are scarce.
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| 11. |
- Wang, Huifu, et al.
(författare)
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Numerical Simulation and Optimization of SCR-DeNOx Systems for Coal-Fired Power Plants Based on a CFD Method
- 2023
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Ingår i: Processes. - : MDPI AG. - 2227-9717. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- In order to solve the problem of the uneven distribution of the flow and ammonia concentration field in the selective catalytic reduction (SCR) denitrification system of a 660 MW coal-fired power plant, a three-dimensional computational fluid dynamics (CFD) model was established at a scale of 1:1. The existing flow guide and ammonia fume mixing device were then calibrated and optimized. The relative standard deviation of the velocity field distribution upstream of the ammonia injection grid (AIG) was optimized from 15.4% to 9.9%, with a reasonable radius of the deflector at the inlet flue elbows, and the relative standard deviation of the velocity field distribution above the inlet surface of the first catalyst layer in the reactor was optimized from 25.4% to 10.2% by adjusting the angle between the deflector and the wall plate of the inlet hood. Additionally, with the use of a double-layer spoiler ammonia fume mixing device, the relative standard deviation of the ammonia mass concentration distribution above the inlet surface of the first catalyst layer in the reactor was optimized from 12.9% to 5.3%. This paper can provide a valuable reference with practical implications for subsequent research.
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| 12. |
- Yuan, Kaifeng, et al.
(författare)
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Numerical Modeling for Rapid Charging of Hydrogen Gas Vessel in Fuel Cell Vehicle
- 2023
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Ingår i: Processes. - : MDPI AG. - 2227-9717. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- As a fuel for power generation, high-pressure hydrogen gas is widely used for transportation, and its efficient storage promotes the development of fuel cell vehicles (FCVs). However, as the filling process takes such a short time, the maximum temperature in the storage tank usually undergoes a rapid increase, which has become a thorny problem and poses great technical challenges to the steady operation of hydrogen FCVs. For security reasons, SAE J2601/ISO 15869 regulates a maximum temperature limit of 85 °C in the specifications for refillable hydrogen tanks. In this paper, a two-dimensional axisymmetric and a three-dimensional numerical model for fast charging of Type III, 35 MPa, and 70 MPa hydrogen vehicle cylinders are proposed in order to effectively evaluate the temperature rise within vehicle tanks. A modified standard k-ε turbulence model is utilized to simulate hydrogen gas charging. The equation of state for hydrogen gas is adopted with the thermodynamic properties taken from the National Institute of Standards and Technology (NIST) database, taking into account the impact of hydrogen gas’ compressibility. To validate the numerical model, three groups of hydrogen rapid refueling experimental data are chosen. After a detailed comparison, it is found that the simulated results calculated by the developed numerical model are in good agreement with the experimental results, with average temperature differences at the end time of 2.56 K, 4.08 K, and 4.3 K. The present study provides a foundation for in-depth investigations on the structural mechanics analysis of hydrogen gas vessels during fast refueling and may supply some technical guidance on the design of charging experiments.
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