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Volume 8
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Processes, Volume 8, Issue 7 (July 2020) – 134 articles

Cover Story (view full-size image): Modeling chromatographic separations is increasingly important in industry. The focus lies on modeling adsorption behavior, and the effect of system contributions on band-broadening is largely neglected. In this study, a bubble trap was chosen as a model system because of its non-standard mixing behavior and the related impact on protein elution though altering the salt gradient. A model using interconnected CSTRs was developed and solved with CADET, and the effect on chromatographic separation was simulated. The results demonstrate that this relatively simple model can capture the impact of system contributions to band broadening. View this paper
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21 pages, 6515 KiB  
Article
A Process-Based Modeling Method for Describing Production Processes of Ship Block Assembly Planning
by Dongsu Jeong, Dohyun Kim, Taihun Choi and Yoonho Seo
Processes 2020, 8(7), 880; https://doi.org/10.3390/pr8070880 - 21 Jul 2020
Cited by 8 | Viewed by 9452
Abstract
Ship block assembly planning is very complex due to the various activities and characteristics of ship production. Therefore, competitiveness in the shipbuilding industry depends on how well a company operates its ship block assembly plan. Many shipbuilders are implementing various studies to improve [...] Read more.
Ship block assembly planning is very complex due to the various activities and characteristics of ship production. Therefore, competitiveness in the shipbuilding industry depends on how well a company operates its ship block assembly plan. Many shipbuilders are implementing various studies to improve their competitiveness in ship block assembly planning, specifically regarding technology usage, such as modeling and simulation (M&S) and Cyber-Physical Systems (CPS). Although these technologies are successfully applied in some production planning systems, it is difficult to tailor ship production planning systems with flexibility due to unexpected situations. Providing a flexible plan for these production planning systems requires a way to describe and review the organic relationships of ship production processes. In this research, a process-based modeling (PBM) method proposes a novel approach to describing the production process of ship block assembly planning by redefining production information based on changing instructions. The proposed method consists of four modeling steps. The first creates a unit model, which includes the products, processes, and resource information for the block. The second designs an integrated network process for linking unit models according to the bill of materials (BOM). The third creates a process-based model that describes the production processes by combining unit models. The fourth generates a simulation model by applying a Petri-net to the process-based model, which analyzes the productivity of the ship’s block assembly processes. PBM identifies the assembly process’ interrelationship and shows that productivity can be reviewed to uncover ship production problems. Full article
(This article belongs to the Special Issue Advances in Sustainable Supply Chains)
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18 pages, 3621 KiB  
Article
Green Method Synthesised Graphene-Silver Electrochemical Nanobiosensors for Ethambutol and Pyrazinamide
by Rachel Fanelwa AjayI, Siphokazi Tshoko, Yonela Mgwili, Siphamandla Nqunqa, Takalani Mulaudzi, Noluthando Mayedwa and Emmanuel Iwuoha
Processes 2020, 8(7), 879; https://doi.org/10.3390/pr8070879 - 21 Jul 2020
Cited by 11 | Viewed by 3839
Abstract
A novel nanobiosensor was constructed with graphene oxide (GO) sheets coupled to pear extract-based green-synthesised silver nanoparticles (Ag-NPs) to which cytochrome P450-2D6 (CYP2D6) enzyme was attached. The biosensor was applied in the electrochemical detection of the tuberculosis (TB) treatment drugs, ethambutol (EMB) and [...] Read more.
A novel nanobiosensor was constructed with graphene oxide (GO) sheets coupled to pear extract-based green-synthesised silver nanoparticles (Ag-NPs) to which cytochrome P450-2D6 (CYP2D6) enzyme was attached. The biosensor was applied in the electrochemical detection of the tuberculosis (TB) treatment drugs, ethambutol (EMB) and pyrazinamide (PZA). The surface morphology of the green-synthesised nanocomposites was studied by performing High-Resolution Transmission Electron Microscopy (HR-TEM) and High-Resolution Scanning Electron Microscopy (HR-SEM). Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy were used for structural analysis, while Ultraviolet Visible (UV-Vis) Spectroscopy was used in the optical characterisation of the nanocomposite material. Electrochemical studies on glassy carbon electrode (GCE), which were done by Cyclic Voltammetry (CV), showed that the GO|Ag-NPs||GCE electrode was highly conductive, and thereby indicating its suitability as a platform for nanobiosensor development. The non-toxic and low-cost green GO|Ag-NPs|CYP2D6||GCE nanobiosensor was used to determine EMB and PZA. The very low limit of detection (LOD) values of the biosensor for EMB (0.2962 × 10−2 nM, S/N = 3) and PZA (0.897 × 10−2 nM, S/N = 3) demonstrate that the green nanobiosensor is more sensitive than other biosensors reported for EMB and PZA. Full article
(This article belongs to the Special Issue Synthesis and Characterization of Carbon–Based Materials for Applications in Chemical and Biological Sensing)
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28 pages, 5705 KiB  
Article
CFD and Experimental Characterization of a Bioreactor: Analysis via Power Curve, Flow Patterns and k L a
by Luis A. Ramírez, Edwar L. Pérez, Cesar García Díaz, Dumar Andrés Camacho Luengas, Nicolas Ratkovich and Luis H. Reyes
Processes 2020, 8(7), 878; https://doi.org/10.3390/pr8070878 - 20 Jul 2020
Cited by 14 | Viewed by 7333
Abstract
Mixing operations in biological processes is of utmost importance due to its effect on scaling-up and heat and mass transfer. This paper presents the characterization of a bench-top bioreactor with different impeller configurations, agitation and oxygen transfer rates, using CFD simulations and experimental [...] Read more.
Mixing operations in biological processes is of utmost importance due to its effect on scaling-up and heat and mass transfer. This paper presents the characterization of a bench-top bioreactor with different impeller configurations, agitation and oxygen transfer rates, using CFD simulations and experimental procedures. Here, it is demonstrated that factors such as the type of impeller and the flow regime can drastically vary the operation as in the preparation of cultures. It was observed that the bioreactor equipped with a Rushton generates a k L a of 0.0056 s−1 for an agitation velocity and airflow rate of 250 RPM and 5 L/min, respectively. It is suitable result for the dissolved oxygen (DO) but requires a considerable amount of power consumption. It is here where the importance of the agitator’s diameter can be observed, since, in the case of the two propeller types studied, lower energy consumption can be achieved with a smaller diameter, as well as a much smaller shear cup 2.376 against 0.723 s−1 by decreasing by 4 cm the standard diameter of an agitated tank (10 cm). Finally, the k L a values obtained for the different configurations are compared with the maximum shear rate values of different cell cultures to highlight the impact of this study and its applicability to different industries that use agitation processes for cell growth. Full article
(This article belongs to the Special Issue Bioreactor System: Design, Modeling and Continuous Production Process)
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13 pages, 4558 KiB  
Article
Numerical Investigation on Coal Combustion in Ultralow CO2 Blast Furnace: Effect of Oxygen Temperature
by Zhenfeng Zhou, Qiujie Yi, Ruihao Wang, Guang Wang and Chunyuan Ma
Processes 2020, 8(7), 877; https://doi.org/10.3390/pr8070877 - 20 Jul 2020
Cited by 6 | Viewed by 3040
Abstract
The cooling effect of room-temperature oxygen in oxygen blast furnaces with top gas recycling (TGR-OBF) delays the coal combustion process. To further explore the oxygen–coal combustion mechanism and intensify coal combustion in TGR-OBF, the effect of oxygen temperature on coal combustion was investigated [...] Read more.
The cooling effect of room-temperature oxygen in oxygen blast furnaces with top gas recycling (TGR-OBF) delays the coal combustion process. To further explore the oxygen–coal combustion mechanism and intensify coal combustion in TGR-OBF, the effect of oxygen temperature on coal combustion was investigated using computational fluid dynamics (CFD). A three-dimensional model was developed to simulate the lance–blowpipe–tuyere–raceway of TGR-OBF. The effect of oxygen temperature at the same oxygen velocity and mass flow on coal combustion was investigated. Results showed the cooling effect of room-temperature oxygen was weakened, and the coal burnout was greatly increased with the increase in oxygen temperature. In particular, the coal burnout increased from 21.64% to 81.98% at the same oxygen velocity when the oxygen temperature increased from 300 to 500 K. The results provide useful reference for the development of TGR-OBF and coal combustion technology. Full article
(This article belongs to the Section Energy Systems)
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10 pages, 4539 KiB  
Article
Effect of Cambered and Oval-Grooved Roll on the Strain Distribution During the Flat Rolling Process of a Wire
by Joong-Ki Hwang
Processes 2020, 8(7), 876; https://doi.org/10.3390/pr8070876 - 20 Jul 2020
Cited by 6 | Viewed by 3614
Abstract
The effect of the roll design on the strain distribution of the flat surface, lateral spreading, and the strain inhomogeneity of a flat-rolled wire were investigated during the flat rolling process. Oval-grooved and cambered rolls with various radii were applied to the flat [...] Read more.
The effect of the roll design on the strain distribution of the flat surface, lateral spreading, and the strain inhomogeneity of a flat-rolled wire were investigated during the flat rolling process. Oval-grooved and cambered rolls with various radii were applied to the flat rolling process based on a numerical simulation. The effective strain on the flat surface of the wire increased when using a cambered roll due to the highly intensified contact pressure on the flat surface, while the effective strain on the flat surface of the wire decreased when using an oval-grooved roll. Lateral spreading decreased when using an oval-grooved roll because the spread in the free surface area of the wire was highly restricted by the oval-grooved roll shape. In contrast, the spread in the surface area increased when using a cambered roll due to the less-restricted metal flow at the free surface. Accordingly, a cambered roll with a small radius is highly recommended in order to improve the surface quality of flat-rolled wires. This is beneficial for industrial plants because the cambered roll can be easily applied in flat rolling plants. Full article
(This article belongs to the Special Issue Process Modeling in Pyrometallurgical Engineering)
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16 pages, 8391 KiB  
Article
Experimental Study on Pressure Distribution and Flow Coefficient of Globe Valve
by Quang Khai Nguyen, Kwang Hyo Jung, Gang Nam Lee, Sung Bu Suh and Peter To
Processes 2020, 8(7), 875; https://doi.org/10.3390/pr8070875 - 20 Jul 2020
Cited by 20 | Viewed by 8964
Abstract
In this study, the pressure distribution and flow coefficient of a globe valve are investigated with a series of experiments conducted in a flow test loop. The experiments are performed on a three-inch model test valve from an eight-inch ANSI (American National Standards [...] Read more.
In this study, the pressure distribution and flow coefficient of a globe valve are investigated with a series of experiments conducted in a flow test loop. The experiments are performed on a three-inch model test valve from an eight-inch ANSI (American National Standards Institute) B16.11—Class 2500# prototype globe valve with various pump speeds and full range of valve openings. Both inherent and installed flow characteristics are measured, and the results show that the flow coefficient depends not only on the valve geometry and valve opening but also on the Reynolds number. When the Reynolds number exceeds a certain value, the flow coefficients are stable. In addition, the pressures at different positions in the upstream and the downstream of the valve are measured and compared with recommendation per ANSI/ISA-75.01 standard. The results show that, in single-phase flow, the discrepancies in pressure between different measurement locations within close range of 10 nominal diameter from the valve are inconsiderable. Full article
(This article belongs to the Section Process Control and Monitoring)
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16 pages, 3760 KiB  
Article
Extraction of Phosphorous from a Phosphorous-Containing Vanadium Titano-Magnetite Tailings by Direct Flotation
by Junhui Xiao, Chao Chen, Wei Ding, Yang Peng, Tao Chen and Kai Zou
Processes 2020, 8(7), 874; https://doi.org/10.3390/pr8070874 - 20 Jul 2020
Cited by 4 | Viewed by 4571
Abstract
In this study, there is 1.42% P2O5 in the P-containing V-Ti magnetite tailings in Miyi Region of China, with the valuable minerals mainly including apatite, and aluminosilicate minerals as the main gangue components. The direction flotation process was used to [...] Read more.
In this study, there is 1.42% P2O5 in the P-containing V-Ti magnetite tailings in Miyi Region of China, with the valuable minerals mainly including apatite, and aluminosilicate minerals as the main gangue components. The direction flotation process was used to recover phosphorous from the low-grade phosphorous-bearing V-Ti magnetite tailings. The results showed that an optimized phosphorous concentrate with a P2O5 grade of 31.35% and P2O5 recovery of 88.02% was obtained by flotation process of one roughing, three scavengings, and three cleanings under roughing conditions, which employed pulp pH of 9, grinding fineness of <0.039 mm occupying 90%, flotation concentration of 25%, and dosages of carboxymethylcellulose, oxidized paraffin wax soap, and pine oil of 400 g/t, 300 g/t, and 20 g/t, respectively. Optimized one scavenging, two scavenging, and three scavenging conditions used a pulp pH of 9, and dosages of carboxymethylcellulose, oxidized paraffin wax soap, and pine oil of 200 g/t, 150 g/t, 10 g/t; 100 g/t, 75 g/t, and 5 g/t; and 100 g/t, 75 g/t, and 5 g/t, respectively. Optimized one cleaning, two cleaning, and three cleaning condition dosages of carboxymethylcellulose of 100 g/t, 50 g/t, and 25 g/t, respectively. Study of analysis and characterization of phosphorous concentrate by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) show that most gangue minerals enter the flotation tailings, the main minerals in phosphorous concentrate are apatite, olivine, and feldspar. Full article
(This article belongs to the Special Issue Green Separation and Extraction Processes)
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17 pages, 3225 KiB  
Article
Andrographis paniculata Extract Relieves Pain and Inflammation in Monosodium Iodoacetate-Induced Osteoarthritis and Acetic Acid-Induced Writhing in Animal Models
by Donghun Lee, Chae Yun Baek, Ji Hong Hwang and Mi-Yeon Kim
Processes 2020, 8(7), 873; https://doi.org/10.3390/pr8070873 - 20 Jul 2020
Cited by 7 | Viewed by 6125
Abstract
Osteoarthritis (OA), being the most prominent degenerative joint disease is affecting millions of elderly people worldwide. Although Andrographis paniculata is an ethnic medicine with a long history of being used as analgesic agent, no study using a monosodium iodoacetate (MIA) model has investigated [...] Read more.
Osteoarthritis (OA), being the most prominent degenerative joint disease is affecting millions of elderly people worldwide. Although Andrographis paniculata is an ethnic medicine with a long history of being used as analgesic agent, no study using a monosodium iodoacetate (MIA) model has investigated its potential activities against OA. In this study, experimental OA was induced in rats with a knee injection of MIA, which represents the pathological characteristics of OA in humans. A. paniculata extract (APE) substantially reversed the loss of hind limb weight-bearing and the cartilage damage resulted from the OA induction in rats. Additionally, the levels of serum pro-inflammatory cytokines, such as IL-1β, IL-6, and TNF-α as well as the concentration of matrix metalloproteinases, including MMP-1, MMP-3, MMP-8, and MMP-13 were decreased by APE administration. Acetic acid-induced writhing responses in mice which quantitatively measure pain were significantly reduced by APE. In vitro, APE inhibited the generation of NO and downregulated the expression of IL-1β, IL-6, COX-2, and iNOS in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The above results suggest the potential use APE as a therapeutic agent against OA. Full article
(This article belongs to the Special Issue Pharmacodynamics Modeling of Anti-inflammatory Drugs)
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25 pages, 14233 KiB  
Article
Unsteady Flow Characteristics of Rotating Stall and Surging in a Backward Centrifugal Fan at Low Flow-Rate Conditions
by Biao Zhou, Ximing He, Hui Yang, Zuchao Zhu, Yikun Wei and Yan Zhang
Processes 2020, 8(7), 872; https://doi.org/10.3390/pr8070872 - 19 Jul 2020
Cited by 7 | Viewed by 4371
Abstract
The steady and unsteady flow characteristics of internal flow in a backward centrifugal fan of double inlet at low flow-rate condition are investigated by computational fluid dynamics in this paper. The investigation aims to reveal insights into generation mechanisms and our physical understanding [...] Read more.
The steady and unsteady flow characteristics of internal flow in a backward centrifugal fan of double inlet at low flow-rate condition are investigated by computational fluid dynamics in this paper. The investigation aims to reveal insights into generation mechanisms and our physical understanding of the rotating stall and surge. The numerical results mainly demonstrate that, with decreasing flow rate, a large number of vortex flows almost increasingly occupy the internal flow of the impeller. The reverse flow and separation vortices increasingly appear near the outlet of volute, and the internal flow of the impeller is completely blocked by the separated vortex flow at low flow-rate conditions. Results indicate that, due to a synchronization of the impeller rotation and separation vortex, these separated vortices act intensely on the pressure surface of the blade with time evolution, and the interaction between the separated vortices and surface of blade increasingly yields small-scale eddies. It is further found that the amplitude of pressure and velocity fluctuations gradually increase with the decrease of flow rate in a certain range. The unsteady characteristics acting on the volute tongue gradually increase in a range of Qd to 0.3 Qd (Qd is the design volume flow rate) with the decrease of flow rate, and the unsteady characteristics acting on the volute tongue are weakened at the working condition of 0.15 Qd. These insights clearly explain the unsteady nature of the rotating stall and surge phenomenon in the double inlet backward centrifugal fan. Full article
(This article belongs to the Collection Modeling, Simulation and Computation on Dynamics of Complex Fluids)
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25 pages, 2905 KiB  
Article
Production of Liquid Milk Protein Concentrate with Antioxidant Capacity, Angiotensin Converting Enzyme Inhibitory Activity, Antibacterial Activity, and Hypoallergenic Property by Membrane Filtration and Enzymatic Modification of Proteins
by Arijit Nath, Burak Atilla Eren, Attila Csighy, Klára Pásztorné-Huszár, Gabriella Kiskó, László Abrankó, Attila Tóth, Emőke Szerdahelyi, Zoltán Kovács, András Koris and Gyula Vatai
Processes 2020, 8(7), 871; https://doi.org/10.3390/pr8070871 - 18 Jul 2020
Cited by 9 | Viewed by 5766
Abstract
Liquid milk protein concentrate with different beneficial values was prepared by membrane filtration and enzymatic modification of proteins in a sequential way. In the first step, milk protein concentrate was produced from ultra-heat-treated skimmed milk by removing milk serum as permeate. A tubular [...] Read more.
Liquid milk protein concentrate with different beneficial values was prepared by membrane filtration and enzymatic modification of proteins in a sequential way. In the first step, milk protein concentrate was produced from ultra-heat-treated skimmed milk by removing milk serum as permeate. A tubular ceramic-made membrane with filtration area 5 × 10−3 m2 and pore size 5 nm, placed in a cross-flow membrane house, was adopted. Superior operational strategy in filtration process was herein: trans-membrane pressure 3 bar, retention flow rate 100 L·h−1, and implementation of a static turbulence promoter within the tubular membrane. Milk with concentrated proteins from retentate side was treated with the different concentrations of trypsin, ranging from 0.008–0.064 g·L−1 in individual batch-mode operations at temperature 40 °C for 10 min. Subsequently, inactivation of trypsin in reaction was done at a temperature of 70 °C for 30 min of incubation. Antioxidant capacity in enzyme-treated liquid milk protein concentrate was measured with the Ferric reducing ability of plasma assay. The reduction of angiotensin converting enzyme activity by enzyme-treated liquid milk protein concentrate was measured with substrate (Abz-FRK(Dnp)-P) and recombinant angiotensin converting enzyme. The antibacterial activity of enzyme-treated liquid milk protein concentrate towards Bacillus cereus and Staphylococcus aureus was tested. Antioxidant capacity, anti-angiotensin converting enzyme activity, and antibacterial activity were increased with the increase of trypsin concentration in proteolytic reaction. Immune-reactive proteins in enzyme-treated liquid milk protein concentrate were identified with clinically proved milk positive pooled human serum and peroxidase-labelled anti-human Immunoglobulin E. The reduction of allergenicity in milk protein concentrate was enzyme dose-dependent. Full article
(This article belongs to the Special Issue Processing Foods: Process Optimization and Quality Assessment)
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13 pages, 831 KiB  
Article
Determination of Vitamins K1, K2 MK-4, MK-7, MK-9 and D3 in Pharmaceutical Products and Dietary Supplements by TLC-Densitometry
by Urszula Hubicka, Agnieszka Padiasek, Barbara Żuromska-Witek and Marek Szlósarczyk
Processes 2020, 8(7), 870; https://doi.org/10.3390/pr8070870 - 18 Jul 2020
Cited by 8 | Viewed by 10036
Abstract
Vitamin K is a group of lipophilic molecules. Forms of vitamin K play an essential role in the activation of specific proteins involved in blood clotting cascade or bone metabolism. Another molecule belonging to the fat-soluble vitamins group that also plays an important [...] Read more.
Vitamin K is a group of lipophilic molecules. Forms of vitamin K play an essential role in the activation of specific proteins involved in blood clotting cascade or bone metabolism. Another molecule belonging to the fat-soluble vitamins group that also plays an important role in calcium metabolism is vitamin D3. The dietary supplements containing vitamins K and D3 are one of the most frequently consumed by patients. The objective of this work was to develop a simple, fast and sensitive thin-layer chromatography (TLC)-densitometric procedure for the simultaneous quantitative analysis of vitamins K and D3 in pharmaceutical products and dietary supplements. The analysis of vitamins was performed on the silica gel RP-18 F₂₅₄s plates with methanol-ethanol-isopropanol in a volume ratio of 15:1:4 as a mobile phase. The densitometric measurements were made at 254 nm. The method was validated by checking the specificity, linearity, precision, recovery, limit of detection, limit of quantification and robustness in accordance with International Conference on Harmonization (ICH) guidelines. The method was shown to be specific, accurate (recoveries were from 95.78 to 104.96%), linear over the tested range (correlation coefficient, exceeding 0.99), and precise (precision and intermediate precision RSD below 2.70% for all analytes). The satisfactory results of the validation of the method indicate that it can be used in the quality control of dietary supplements and pharmaceutical products containing vitamins K and D3. Full article
(This article belongs to the Special Issue Applications of Chromatographic Separation Techniques in Food and Chemistry)
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10 pages, 8987 KiB  
Article
Development of a Freeze-Drying Stage for In-Situ µ-CT Measurements
by Mathias Hilmer, Sebastian Gruber and Petra Foerst
Processes 2020, 8(7), 869; https://doi.org/10.3390/pr8070869 - 18 Jul 2020
Cited by 3 | Viewed by 3389
Abstract
This paper shows the development of a freeze-drying stage for in-situ μ-CT measurements. The stage can operate in a temperature range of −40 °C up to 70 °C, and a pressure range from atmospheric pressure to 7 Pa at the sample holder. To [...] Read more.
This paper shows the development of a freeze-drying stage for in-situ μ-CT measurements. The stage can operate in a temperature range of −40 °C up to 70 °C, and a pressure range from atmospheric pressure to 7 Pa at the sample holder. To get the best visualization of the probe, it is fundamental that the materials around the sample holder are not absorbing most of the radiation. For this reason, we built an axial symmetrical stage built out of polyetheretherketon (PEEK). A test of the stage by different freeze-drying experiments with maltodextrin and sucrose particles and solutions demonstrated its suitability to visualize the freeze-drying processes in-situ. It was possible to track the drying front during the process by radiographic and tomographic measurements, as well as to visually resolve the ice crystals and porous structure in tomographic measurements. Using different samples and process parameters, we showed that the freeze-drying stage is not only suitable for in-situ µ-CT measurements, but also allows us to use the stage for other imaging methods such as neutron imaging, and for any sample where a controlled environment is needed. Full article
(This article belongs to the Special Issue Modern Freeze Drying Design for More Efficient Processes)
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24 pages, 3349 KiB  
Article
Integrated Biorefinery of Empty Fruit Bunch from Palm Oil Industries to Produce Valuable Biochemicals
by Rendra Hakim Hafyan, Lupete K. Bhullar, Shuhaimi Mahadzir, Muhammad Roil Bilad, Nik Abdul Hadi Nordin, Mohd Dzul Hakim Wirzal, Zulfan Adi Putra, Gade Pandu Rangaiah and Bawadi Abdullah
Processes 2020, 8(7), 868; https://doi.org/10.3390/pr8070868 - 18 Jul 2020
Cited by 18 | Viewed by 7545
Abstract
Empty fruit bunch (EFB) utilization to produce valuable bio-chemicals is seen as an economical and sustainable alternative to waste management in palm oil industries. This work proposed an integrated biorefinery configuration of EFB valorization considering sustainability pillars—namely, economic, environmental, and safety criteria. Techno-economic [...] Read more.
Empty fruit bunch (EFB) utilization to produce valuable bio-chemicals is seen as an economical and sustainable alternative to waste management in palm oil industries. This work proposed an integrated biorefinery configuration of EFB valorization considering sustainability pillars—namely, economic, environmental, and safety criteria. Techno-economic analysis, life cycle assessment, and hazard identification ranking methods were used to estimate annual profit, global warming potential (GWP), fire explosion damage index (FEDI), and toxicity damage index (TDI) of the proposed integrated biorefinery. A multi-objective optimization problem was then formulated and solved for simultaneous maximization of profit and minimization of GWP, FEDI and TDI. The resulting Pareto-optimal solutions convey the trade-off among the economic, environmental, and safety performances. To choose one of these optimal solutions for implementation, a combined approach of fuzzy analytical hierarchy process and a technique for order preference by similarity to ideal solution was applied. For this selection, the economic criterion was more preferred, followed by the safety and environmental criterion; thus, the optimal solution selected for integrated biorefinery configuration had the highest annual profit, which was at the maximum capacity of 100 ton/h of EFB. It can fulfill the global demand of xylitol (by 55%), levulinic acid (by 98%), succinic acid (by 25%), guaiacol (by 90%), and vanillin (by 12%), and has annual profit, GWP, FEDI, and TDI of 932 M USD/year, 284 tonCO2-eq, 595, and 957, respectively. Full article
(This article belongs to the Collection Multi-Objective Optimization of Processes)
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3 pages, 167 KiB  
Editorial
Special Issue: Application of Advanced Oxidation Processes
by Ciro Bustillo-Lecompte, Jose Colina-Marquez and Lars Rehmann
Processes 2020, 8(7), 867; https://doi.org/10.3390/pr8070867 - 18 Jul 2020
Cited by 1 | Viewed by 3011
Abstract
Advanced oxidation processes (AOPs) are nowadays not only considered as a complementary treatment option but as an attractive alternative to conventional methods [...] Full article
(This article belongs to the Special Issue Application of Advanced Oxidation Processes)
27 pages, 9981 KiB  
Article
Digital Twin for Extraction Process Design and Operation
by Lukas Uhlenbrock, Christoph Jensch, Martin Tegtmeier and Jochen Strube
Processes 2020, 8(7), 866; https://doi.org/10.3390/pr8070866 - 17 Jul 2020
Cited by 19 | Viewed by 5027
Abstract
Traditional extraction processes of natural product are widespread, especially in regulated industries. Possibilities of extraction development and manufacturing optimization in regulated industries is limited. Regulatory approvals are often based on traditional preparations of phyto-pharmaceuticals. The dependence on traditional processes can result in sub-optimal [...] Read more.
Traditional extraction processes of natural product are widespread, especially in regulated industries. Possibilities of extraction development and manufacturing optimization in regulated industries is limited. Regulatory approvals are often based on traditional preparations of phyto-pharmaceuticals. The dependence on traditional processes can result in sub-optimal extraction parameters causing unnecessary costs and product variability. Innovative methods like Quality-by-Design (QbD), including process analytical technology (PAT), open opportunities for manufacturers to cope with regulatory demanded, narrow batch-to-batch variability. In addition, such validated process models represent perfect digital twins which could be utilized for advanced process control and life cycle analysis. Full article
(This article belongs to the Section Biological Processes and Systems)
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18 pages, 3419 KiB  
Article
Bioink Temperature Influence on Shear Stress, Pressure and Velocity Using Computational Simulation
by J. Carlos Gómez-Blanco, Enrique Mancha-Sánchez, Alfonso C. Marcos, Manuel Matamoros, Antonio Díaz-Parralejo and J. Blas Pagador
Processes 2020, 8(7), 865; https://doi.org/10.3390/pr8070865 - 17 Jul 2020
Cited by 24 | Viewed by 5634
Abstract
Bioinks are usually cell-laden hydrogels widely studied in bioprinting performing experimental tests to tune their rheological properties, thus increasing research time and development costs. Computational Fluids Dynamics (CFD) is a powerful tool that can minimize iterations and costs simulating the material behavior using [...] Read more.
Bioinks are usually cell-laden hydrogels widely studied in bioprinting performing experimental tests to tune their rheological properties, thus increasing research time and development costs. Computational Fluids Dynamics (CFD) is a powerful tool that can minimize iterations and costs simulating the material behavior using parametric changes in rheological properties under testing. Additionally, most bioinks have specific functionalities and their properties might widely change with temperature. Therefore, commercial bioinks are an excellent way to standardize bioprinting process, but they are not analyzed in detail. Therefore, the objective of this work is to study how three temperatures of the Cellink Bioink influence shear stress pressure and velocity through computational simulation. A comparison of three conical nozzles (20, 22, and 25G) for each temperature has been performed. The results show that shear stress, pressure, and velocity vary in negligible ranges for all combinations. Although these ranges are small and define a good thermo-responsive bioink, they do not generate a filament on the air and make drops during extrusion. In conclusion, this bioink provides a very stable behavior with low shear stress, but other bioprinting parameters must be set up to get a stable filament width. Full article
(This article belongs to the Collection Modeling, Simulation and Computation on Dynamics of Complex Fluids)
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18 pages, 3296 KiB  
Article
Utilization of Industry 4.0 Related Equipment in Assembly Line Balancing Procedure
by Nikola Gjeldum, Bashir Salah, Amanda Aljinovic and Sajjad Khan
Processes 2020, 8(7), 864; https://doi.org/10.3390/pr8070864 - 17 Jul 2020
Cited by 14 | Viewed by 5640
Abstract
In recent decades, production in high-volume/low-variety batches is replaced with low-volume/high-variety production type. This type of production demands excessive flows of both material and information. Recent advances in information and communication technologies (ICT), together with the concept of cyber-psychical system (CPS) enable the [...] Read more.
In recent decades, production in high-volume/low-variety batches is replaced with low-volume/high-variety production type. This type of production demands excessive flows of both material and information. Recent advances in information and communication technologies (ICT), together with the concept of cyber-psychical system (CPS) enable the concept of Industry 4.0 (I4.0). In this paper, the performance of I4.0 related equipment implementation is presented in iterative assembly line balancing (ALB) process of a gearbox assembly line. Largest candidate rule method through spreadsheet simulation was used for tasks reallocations, with the objective to minimize the cycle time when the number of stations is fixed. Utilization of human analysts using snap back method for manual data gathering process still shown advantage over I4.0 equipment utilization in manual ALB. The assembly process is performed in the learning factory environment, and it is considered as very close to real industry process. The major conclusion is that I4.0 is excellent in process data monitoring and product tracking, but activities to be performed to effectively exploit I4.0 is demanding for task reallocations during the balancing procedure. Nevertheless, future enhancements of I4.0 system are listed to bridge this gap and to increase I4.0 system usefulness in the manual assembly line balancing process. Full article
(This article belongs to the Section Advanced Digital and Other Processes)
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17 pages, 1293 KiB  
Article
Bioavailability of Sulfur from Waste Obtained during Biogas Desulfurization and the Effect of Sulfur on Soil Acidity and Biological Activity
by Monika Tabak, Aneta Lisowska and Barbara Filipek-Mazur
Processes 2020, 8(7), 863; https://doi.org/10.3390/pr8070863 - 17 Jul 2020
Cited by 20 | Viewed by 4392
Abstract
Sulfur deficiency has been recognized as a limiting factor for crop production in many regions of the world. A 120-day incubation experiment was conducted to assess the effect of the applied waste elemental sulfur on sulfur bioavailability in soil. Four doses of sulfur [...] Read more.
Sulfur deficiency has been recognized as a limiting factor for crop production in many regions of the world. A 120-day incubation experiment was conducted to assess the effect of the applied waste elemental sulfur on sulfur bioavailability in soil. Four doses of sulfur were applied: 10, 20, 30 and 60 mg S kg−1 dry matter (d.m.) of soil. In order to assess the effect of soil pH adjustment on sulfur oxidation, the research was conducted on two sets of soil samples: one set of soil samples had natural pH, and the second one was limed before sulfur application. Application of waste sulfur slightly affected the soil pH, and increased the content of available sulfur in soil proportionally to sulfur dose. A beneficial effect of waste sulfur application on soil dehydrogenase and catalase activity was found. Liming reduced soil acidity, and significantly increased sulfate content and soil enzymatic activity. Waste elemental sulfur may be an alternative source of sulfur, supplementing the deficiencies of this element in soils. The described way of sulfur waste reuse corresponds with the increasingly common approach to create waste-free technologies in all economy. Full article
(This article belongs to the Special Issue Applications of Bioprocess Processes in Environmental Protection and Purification)
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19 pages, 12933 KiB  
Article
A Numerical Investigation on the Optimization of Uneven Flow in a Marine De-SOx Scrubber
by Hao Guo, Song Zhou, Majed Shreka and Yongming Feng
Processes 2020, 8(7), 862; https://doi.org/10.3390/pr8070862 - 17 Jul 2020
Cited by 9 | Viewed by 3995
Abstract
According to regulations from the International Maritime Organization (IMO), the sulfur content of vessels must not exceed 0.5% outside the Emission Control Areas (ECAs) starting from 2020. The marine exhaust gas desulfurization (De-SOx) system is the most feasible technology to meet the increasing [...] Read more.
According to regulations from the International Maritime Organization (IMO), the sulfur content of vessels must not exceed 0.5% outside the Emission Control Areas (ECAs) starting from 2020. The marine exhaust gas desulfurization (De-SOx) system is the most feasible technology to meet the increasing regulations, but there is always a large swirl at the bottom of the scrubber causing uneven flow past the sprays. Solving this problem by adjusting the spray is a feasible method. The exhaust gas at 485 K and injection liquid at 305 K are simulated to optimize the flow field in a De-SOx scrubber. The results indicated that the flue gas was easily concentrated in the left side area of the scrubber and this part of hot gas could escape from the scrubber. By controlling the nozzles distribution and the nozzles angle, it was possible to reduce the droplets to hit the wall and improve the utilization rate of the washing liquid. The nozzles were arranged up and down in different positions, which reduced the escape amount of exhaust gas in the strong offset area. The new arrangement of nozzles made the flow field distribution inside the scrubber more uniform and increased the gas–liquid reaction time Although the pressure drop under outermost nozzles 45° injection was smaller than the vertical injection, the flow field under 45° injection became more complex and the outlet gas velocity became larger. Full article
(This article belongs to the Special Issue Advanced Liquid Waste and Gas Waste Treatment Processes)
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10 pages, 2567 KiB  
Article
Influence of Humidity on Performance of Single Chamber Air-Cathode Microbial Fuel Cells with Different Separators
by Mungyu Lee, Sanath Kondaveeti, Taeyeon Jeon, Inhae Kim and Booki Min
Processes 2020, 8(7), 861; https://doi.org/10.3390/pr8070861 - 17 Jul 2020
Cited by 5 | Viewed by 3158
Abstract
The maximum performance of microbial fuel cells (MFCs) is significantly affected by the reduction reactions in the cathode, but their optimum condition is not fully understood yet. The air-cathode MFC operations with different separators (Nafion 117 and polypropylene (PP80) were evaluated at various [...] Read more.
The maximum performance of microbial fuel cells (MFCs) is significantly affected by the reduction reactions in the cathode, but their optimum condition is not fully understood yet. The air-cathode MFC operations with different separators (Nafion 117 and polypropylene (PP80) were evaluated at various relative humidity (RH) at the cathode chamber. Air cathode MFCs with a Nafion 117 separator at RH of 90 ± 2% produced the highest cell voltage of 0.35 V (600 Ω) and power density of 116 mW/m2. With a PP80 separator, the maximum power generation of 381 mW/m2 was obtained at a relatively lower RH of 30 ± 2%. The cyclic voltammogram and Tafel analysis indicated that the best performance of cathodic oxygen reduction reactions could be observed at 90% RH for Nafion and 50% RH for the PP80 separator. Additionally, the RH conditions also affected the anodic reactions and oxygen mass transfer rates to the anode chamber through the cathode and separators. This study suggests that the optimum RH condition at the cathode is important in order to obtain a high performance of MFC operations and needs to be controlled at different optimum levels depending on the characteristics of the separators. Full article
(This article belongs to the Special Issue Development and Applications of Bioelectrochemical Systems)
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21 pages, 415 KiB  
Article
Structural and Thermal Characterization of Novel Organosolv Lignins from Wood and Herbaceous Sources
by Anna Trubetskaya, Heiko Lange, Bernd Wittgens, Anders Brunsvik, Claudia Crestini, Ulrika Rova, Paul Christakopoulos, J. J. Leahy and Leonidas Matsakas
Processes 2020, 8(7), 860; https://doi.org/10.3390/pr8070860 - 17 Jul 2020
Cited by 32 | Viewed by 4277
Abstract
This study demonstrates the effects of structural variations of lignins isolated via an organosolv process from different woody and herbaceous feedstocks on their thermal stability profiles. The organosolv lignins were first analysed for impurities, and structural features were determined using the default set [...] Read more.
This study demonstrates the effects of structural variations of lignins isolated via an organosolv process from different woody and herbaceous feedstocks on their thermal stability profiles. The organosolv lignins were first analysed for impurities, and structural features were determined using the default set of gel permeation chromatography, FT-IR spectroscopy, quantitative 31 P NMR spectroscopy and semi-quantitative 1 H- 13 C HSQC analysis. Pyrolysis-, O 2 - and CO 2 -reactivity of the organosolv lignins were investigated by thermogravimetric analysis (TGA), and volatile formation in various heating cycles was mapped by head-space GC-MS analysis. Revealed reactivities were correlated to the presence of identified impurities and structural features typical for the organosolv lignins. Data suggest that thermogravimetric analysis can eventually be used to delineate a lignin character when basic information regarding its isolation method is available. Full article
(This article belongs to the Special Issue Biochemical and Thermochemical Conversion Processes of Lignicellulosic Biomass Fractionated Streams)
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9 pages, 2320 KiB  
Article
Preparation of Biocomposite Soft Nanoparticles Composed of Poly(Propylene Oxide) and the Polymer-Binding Peptides
by Toshiki Sawada, Hiroki Fukuta and Takeshi Serizawa
Processes 2020, 8(7), 859; https://doi.org/10.3390/pr8070859 - 17 Jul 2020
Cited by 1 | Viewed by 3085
Abstract
The molecular recognition capability of naturally occurring biomolecules is generally expressed against biomolecules in the biological milieu. Recently, it was demonstrated that the specific interactions of biomolecules such as short peptides were applicable to artificial materials. We have developed peptides with specific affinities [...] Read more.
The molecular recognition capability of naturally occurring biomolecules is generally expressed against biomolecules in the biological milieu. Recently, it was demonstrated that the specific interactions of biomolecules such as short peptides were applicable to artificial materials. We have developed peptides with specific affinities for synthetic polymers toward functional biocomposite polymeric materials. In this study, we demonstrated the preparation of biocomposite nanoparticles composed of poly(propylene oxide) (PPO) and PPO-binding peptides. A simple injection of a concentrated PPO solution dissolved in an organic solvent into the peptide solution under sonication resulted in the formation of nanospherical structures. Morphological observation indicated characteristic softness and high applicability as a molecular carrier of the biocomposite nanoparticles. Structural characterization of PPO and the PPO-binding peptide revealed the structural conformability of these molecules to interact specifically with each other. Our findings expand the potential applicability of polymer-binding peptides for the future construction of biomedical materials composed of peptides and various polymers. Full article
(This article belongs to the Special Issue Advances of Peptide Engineering)
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11 pages, 1195 KiB  
Article
Evaluation of the Lipophilicity of New Anticancer 1,2,3-Triazole-Dipyridothiazine Hybrids Using RP TLC and Different Computational Methods
by Beata Morak-Młodawska, Krystian Pluta and Małgorzata Jeleń
Processes 2020, 8(7), 858; https://doi.org/10.3390/pr8070858 - 17 Jul 2020
Cited by 12 | Viewed by 4078
Abstract
Two new anticancer-active 1,2,3-triazole-dipyridothiazine hybrids were evaluated for their lipophilicity using thin-layer chromatography (TLC) and computational methods. The experimental lipophilicity was evaluated with mobile phases (mixtures of TRIS buffer and acetone), exploiting a linear correlation between the retention parameter (RM) [...] Read more.
Two new anticancer-active 1,2,3-triazole-dipyridothiazine hybrids were evaluated for their lipophilicity using thin-layer chromatography (TLC) and computational methods. The experimental lipophilicity was evaluated with mobile phases (mixtures of TRIS buffer and acetone), exploiting a linear correlation between the retention parameter (RM) and the volume of acetone. The relative lipophilicity parameter (RM0) was obtained by extrapolation to 0% acetone concentration. This parameter was intercorrelated with a specific hydrophobic surface area (b) revealing two congeneric subgroups: hybrids of 1,2,3-triazole-2,7-diazaphenothiazines and 1,2,3-triazole-3,6-diazaphenothiazines. The parameter RM0 was converted into the absolute lipophilicity parameter logPTLC using a calibration curve prepared on the basis of compounds of known logP values. Triazole–dipyridothiazine hybrids turned out to be medium lipophilic with logPTLC values of 1.232–2.979. The chromatographically established parameter logPTLC was compared to the calculated lipophilic parameter logPcalcd obtained with various algorithms. The lipophilicity was correlated with molecular descriptors and ADME properties. The new triazole–dipyridothiazine hybrids followed Lipinski’s rule of five. The lipophilicity of these hybrids was dependent on the substituents attached to the triazole ring and the location of the azine nitrogen atoms. Full article
(This article belongs to the Special Issue Applications of Chromatographic Separation Techniques in Food and Chemistry)
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40 pages, 9192 KiB  
Review
Larvae Mediated Valorization of Industrial, Agriculture and Food Wastes: Biorefinery Concept through Bioconversion, Processes, Procedures, and Products
by Harish Karthikeyan Ravi, Antoine Degrou, Jérôme Costil, Christophe Trespeuch, Farid Chemat and Maryline Abert Vian
Processes 2020, 8(7), 857; https://doi.org/10.3390/pr8070857 - 17 Jul 2020
Cited by 92 | Viewed by 16838
Abstract
Each year, the food supply chain produces more than 1.3 billion tons of food and agricultural waste, which poses serious environmental problems. The loss of the massive quantity of secondary and primary metabolites retrievable from this resource is a significant concern. What if [...] Read more.
Each year, the food supply chain produces more than 1.3 billion tons of food and agricultural waste, which poses serious environmental problems. The loss of the massive quantity of secondary and primary metabolites retrievable from this resource is a significant concern. What if there is a global solution that caters to the numerous problems arising due to the humongous volume of waste biomass generated in every part of the world? Insects, the tiny creatures that thrive in decaying organic matter, which can concentrate the nutrients present in dilute quantities in a variety of by-products, are an economically viable option. The bioconversion and nutritional upcycling of waste biomass with insects yield high-value products such as protein, lipids, chitin and frass. Insect-derived proteins can replace conventional protein sources in feed formulations. Notably, the ability of the black soldier fly (BSF) or Hermetia illucens to grow on diverse substrates such as agri-food industry side streams and other organic waste proves advantageous. However, the data on industrial-scale extraction, fractionation techniques and biorefinery schemes for screening the nutritional potential of BSF are scarce. This review attempts to break down every facet of insect processing and analyze the processing methods of BSF, and the functional properties of nutrients obtained thereof. Full article
(This article belongs to the Special Issue Sustainable Development of Waste towards Green Growth)
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13 pages, 1664 KiB  
Article
Post-Polymerization Heat Effect in the Production of Polyamide 6 by Bulk Quasiliving Anionic Ring-Opening Polymerization of ε-Caprolactam with Industrial Components: A Green Processing Technique
by Zsófia Osváth, Anita Szőke, Szabolcs Pásztor, Györgyi Szarka, László Balázs Závoczki and Béla Iván
Processes 2020, 8(7), 856; https://doi.org/10.3390/pr8070856 - 17 Jul 2020
Cited by 9 | Viewed by 4742
Abstract
Bulk, solventless anionic ring-opening polymerization (AROP) of ε-caprolactam (CPL) with high yields, without side products and with short reaction times, initiated by caprolactamate-carbamoylcaprolactam initiating systems belong to green polymerization processes, leading to poly(ε-caprolactam) (Polyamide 6, PA6, Nylon 6). However, the effect of post-polymerization [...] Read more.
Bulk, solventless anionic ring-opening polymerization (AROP) of ε-caprolactam (CPL) with high yields, without side products and with short reaction times, initiated by caprolactamate-carbamoylcaprolactam initiating systems belong to green polymerization processes, leading to poly(ε-caprolactam) (Polyamide 6, PA6, Nylon 6). However, the effect of post-polymerization heat (i.e., slow, technically feasible cooling) on the fundamental characteristics of the resulting polymers such as yield and molecular weight distributions (MWDs) have not been revealed thus far. Significant post-polymerization effect was found by us in terms of both monomer conversions and MWDs by carrying out CPL polymerization with industrial components under conditions mimicking thermoplastic reaction transfer molding (T-RTM). Remarkably, higher monomer conversions and molecular weights (MWs) were obtained for Polyamide 6 samples prepared without quenching than that for the quenched polymers at the same reaction times. Independent of quenching or non-quenching, Mn of the resulting polymers as a function of conversion fell in the theoretical line of quasiliving AROP of CPL. At high monomer conversions, significant increase of the MW and broadening of the MWDs occurred, indicating pronounced chain–chain coupling. These findings have fundamental importance for designing processing conditions for in situ polymerization processes of ε-caprolactam by various techniques such as T-RTM, reaction injection molding (RIM), and other processing methods of Polyamide 6. Full article
(This article belongs to the Special Issue Green Synthesis Processes of Polymers & Composites)
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21 pages, 570 KiB  
Article
Modular Model Predictive Control upon an Existing Controller
by Wai Hou Lio, John Anthony Rossiter and Bryn Llywelyn Jones
Processes 2020, 8(7), 855; https://doi.org/10.3390/pr8070855 - 16 Jul 2020
Cited by 1 | Viewed by 3168
Abstract
The availability of predictions of future system inputs has motivated research into preview control to improve set-point tracking and disturbance rejection beyond that achievable via conventional feedback control. The design of preview controllers, typically based upon model predictive control (MPC) for its constraint [...] Read more.
The availability of predictions of future system inputs has motivated research into preview control to improve set-point tracking and disturbance rejection beyond that achievable via conventional feedback control. The design of preview controllers, typically based upon model predictive control (MPC) for its constraint handling properties, is often performed in a monolithic nature, coupling the feedback and feed-forward problems. This can create problems, such as: (i) an additional feedback loop is introduced by MPC, which alters the closed-loop dynamics of the existing feedback compensator, potentially resulting in a deterioration of the nominal sensitivities and robustness properties of an existing closed-loop and (ii) the default preview action from MPC can be poor, degrading the original feedback control performance. In our previous work, the former problem is addressed by presenting a modular MPC design on top of a given output-feedback controller, which retains the nominal closed-loop robustness and frequency-domain properties of the latter, despite the addition of the preview design. In this paper, we address the second problem; the preview compensator design in the modular MPC formulation. Specifically, we derive the key conditions that ensure, under a given closed-loop tuning, the preview compensator within the modular MPC formulation is systematic and well-designed in a sense that the preview control actions complement the existing feedback control law rather than opposing it. In addition, we also derive some important results, showing that the modular MPC can be implemented in a cascade over any given linear controllers and the proposed conditions hold, regardless of the observer design for the modular MPC. The key benefit of the modular MPC is that the preview control with constraint handling can be implemented without replacing the existing feedback controller. This is illustrated through some numerical examples. Full article
(This article belongs to the Special Issue Redesign Processes in the Age of the Fourth Industrial Revolution)
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3 pages, 155 KiB  
Editorial
Special Issue: Bioprocess Monitoring and Control
by Bernd Hitzmann
Processes 2020, 8(7), 854; https://doi.org/10.3390/pr8070854 - 16 Jul 2020
Cited by 1 | Viewed by 2317
Abstract
Bioprocesses can be found in different areas such as the production of food, feed, energy, chemicals, and pharmaceuticals [...] Full article
(This article belongs to the Special Issue Bioprocess Monitoring and Control)
15 pages, 8417 KiB  
Article
Research on the Mechanical Efficiency of High-Speed 2D Piston Pumps
by Yu Huang, Jian Ruan, Chenchen Zhang, Chuan Ding and Sheng Li
Processes 2020, 8(7), 853; https://doi.org/10.3390/pr8070853 - 16 Jul 2020
Cited by 25 | Viewed by 3883
Abstract
Since many studies on axial piston pumps aim at enhancing their high power-weight ratio, many researchers have focused on the generated mechanical losses by the three friction pairs in such pumps and attempted to diminish them through abundant and new structural designs of [...] Read more.
Since many studies on axial piston pumps aim at enhancing their high power-weight ratio, many researchers have focused on the generated mechanical losses by the three friction pairs in such pumps and attempted to diminish them through abundant and new structural designs of the pump’s components. In this paper, a high-speed 2D piston pump is introduced and its architecture is specifically described. Afterward, a mathematical model is established to study the pump’s mechanical efficiency, including the mechanical losses caused by the viscosity and stirring oil. Additionally, in this study the influences of the rotational speed, the different load pressures, and the rolling friction coefficient between the cone roller and the guiding rail are considered and discussed. By building a test rig, a series of experiments were carried out to prove that the mechanical efficiency was accurately predicted by this model at low load pressures. However, there was an increasing difference between the test results and the analytical outcomes at high pressures. Nevertheless, it is still reasonable to conclude that the rolling friction coefficient changes as the load pressure increases, which leads to a major decrease in the mechanical efficiency in experiments. Full article
(This article belongs to the Section Process Control and Monitoring)
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17 pages, 1335 KiB  
Article
Study of the Digestate as an Innovative and Low-Cost Adsorbent for the Removal of Dyes in Wastewater
by Sicong Yao, Massimiliano Fabbricino, Marco Race, Alberto Ferraro, Ludovico Pontoni, Oriella Aimone and Yao Chen
Processes 2020, 8(7), 852; https://doi.org/10.3390/pr8070852 - 16 Jul 2020
Cited by 11 | Viewed by 3107
Abstract
Digestate, as an urban solid waste, was considered as an innovative adsorbent for colorant polluted wastewater. Batch adsorption experiments were carried out using digestate as an adsorbent material to remove various dyes belonging to different categories. The removal rate and adsorption capacity of [...] Read more.
Digestate, as an urban solid waste, was considered as an innovative adsorbent for colorant polluted wastewater. Batch adsorption experiments were carried out using digestate as an adsorbent material to remove various dyes belonging to different categories. The removal rate and adsorption capacity of dyes were evaluated and the dose of digestate, contact time, and initial dye concentration were studied. The maximum removal rate was approximately 96% for Methylene Blue. The equilibrium time for the Methylene Blue was 4 h, while for other dyes, a longer contact time was required to reach the equilibrium. The suspicion of colloidal matter release into the solution from solid fraction of the digestate led to the investigation of the consequence of a washing step of the digestate adsorbent upstream the adsorption experiment. Washed and not washed adsorbents were tested and the differences between them in terms of dye removal were compared. Moreover, experimental data were fitted by pseudo-first order, pseudo-second order, and intra-partial diffusion kinetic models as well as Langmuir, Freundlich, and Sips isotherm models. The results from fitted models showed that the adsorption of various dyes onto the digestate was mostly well fitted by the Langmuir isotherm and pseudo-second-order kinetic model. Full article
(This article belongs to the Special Issue Wastewater Treatment Processes)
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36 pages, 1150 KiB  
Article
Robust Multi-Stage Nonlinear Model Predictive Control Using Sigma Points
by Sakthi Thangavel, Radoslav Paulen and Sebastian Engell
Processes 2020, 8(7), 851; https://doi.org/10.3390/pr8070851 - 16 Jul 2020
Cited by 4 | Viewed by 3679
Abstract
We address the question of how to reduce the inevitable loss of performance that is incurred by robust multi-stage NMPC due to the lack of knowledge compared to the case where the exact plant model (no uncertainty) is available. Multi-stage NMPC in the [...] Read more.
We address the question of how to reduce the inevitable loss of performance that is incurred by robust multi-stage NMPC due to the lack of knowledge compared to the case where the exact plant model (no uncertainty) is available. Multi-stage NMPC in the usual setting over-approximates a continuous parametric uncertainty set by a box and includes the corners of the box and the center point into the scenario tree. If the uncertainty set is not a box, this augments the uncertainty set and results in a performance loss. In this paper, we propose to mitigate this problem by two different approaches where the scenario tree of the multi-stage NMPC is built using sigma points. The chosen sigma points help to capture the true mean and covariance of the uncertainty set more precisely. The first method computes a box over-approximation of the reachable set of the system states whereas the second method computes a box over-approximation of the reachable set of the constraint function using the unscented transformation. The advantages of the proposed schemes over the traditional multi-stage NMPC are demonstrated using simulation studies of a simple semi-batch reactor and a more complex industrial semi-batch polymerization reactor benchmark example. Full article
(This article belongs to the Special Issue Optimization-Driven Methods for Optimal Operation and Control Strategies)
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