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Volume 8
Issue 7
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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 9376
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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Figure 1

Figure 1
<p>Hierarchy of the ship production process, production layer, production planning, and company strategies.</p> Full article ">Figure 2
<p>Overall flow of the process-based modeling methods for ship production planning.</p> Full article ">Figure 3
<p>Typical structure information of large assembly blocks (Left: hierarchy structure information of large assembly blocks. Right: work breakdown structure of TT1 blocks based on the bill of materials (BOM)).</p> Full article ">Figure 4
<p>The production process definition of large assembly blocks: (<b>a</b>) production process of a panel block, and (<b>b</b>) production process of a curved block.</p> Full article ">Figure 5
<p>An example of a unit model that combines the products, processes, and resources.</p> Full article ">Figure 6
<p>Creation of integrated data through the relationships between the BOM, activities, and activity relationships data.</p> Full article ">Figure 7
<p>Workflow modeling patterns: (<b>a</b>) sequential operation, (<b>b</b>) parallel operation (AND-split), (<b>c</b>) choice operation (OR-split), (<b>d</b>) synchronized operation (AND-join), and (<b>e</b>) join/merge operation (OR-join).</p> Full article ">Figure 8
<p>A TT1 block workflow example.</p> Full article ">Figure 9
<p>Flowchart of the integrated network process. PPR: product, process, and resource.</p> Full article ">Figure 10
<p>Process-based model for describing a large assembly factory.</p> Full article ">Figure 11
<p>Illustration demonstrating a TT1 block’s production process through the process-based modeling (PBM) method.</p> Full article ">Figure 12
<p>Process-based model through the Petri-net model (QPNet: quick Petri-net simulator).</p> Full article ">Figure 13
<p>Productivity analysis of the ship production process through four key elements: (<b>a</b>) make-span, (<b>b</b>) throughput, (<b>c</b>) resource usage, and (<b>d</b>) resource cost. SP: space. SC: schedule.</p> Full article ">
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 3769
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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Figure 1

Figure 1
<p>(<b>a</b>) FTIR and (<b>b</b>) UV-vis spectra of Ag-NPs, GO|Ag-NPs and pear extracts.</p> Full article ">Figure 2
<p>HR-TEM image of (<b>a</b>) graphene oxide (GO), (<b>b</b>) GO|Ag-NPs and (<b>c</b>) SAED pattern of GO|Ag-NPs.</p> Full article ">Figure 3
<p>XRD pattern of (<b>a</b>) graphite and graphene oxide (<b>b</b>) GO|Ag-NPs and the (<b>c</b>) histogram for GO|Ag-NPs.</p> Full article ">Figure 4
<p>High-resolution scanning electron microscopy (HR-SEM) images showing (<b>a</b>) GO and (<b>b</b>) GO|Ag-NPs.</p> Full article ">Figure 5
<p>Raman spectra of GO and GO|Ag-NPs.</p> Full article ">Figure 6
<p>Cyclic voltammetry (CV) of bare glassy carbon electrode (GCE), GO|Ag-NPs|GCE and GO|Ag-NPs|CYT2D6|GCE in pH 7.4, 0.1 M PBS buffer solution at 50 mV s<sup>−1</sup>.</p> Full article ">Figure 7
<p>CV analysis of GO|Ag-NPs|CYP2D6||GCE at 10 mV s<sup>−1</sup> interval scan rate intervals.</p> Full article ">Figure 8
<p>CV of bare GCE, GO|Ag-NPs|CYP2D6 and (<b>a</b>) 50 µM of ethambutol and (<b>b</b>) 50 µM of pyrazinamide at 50 mV s<sup>−1</sup>.</p> Full article ">Figure 8 Cont.
<p>CV of bare GCE, GO|Ag-NPs|CYP2D6 and (<b>a</b>) 50 µM of ethambutol and (<b>b</b>) 50 µM of pyrazinamide at 50 mV s<sup>−1</sup>.</p> Full article ">Figure 9
<p>(<b>a</b>) Calibration curve for the EMB nanobiosensor and CV of the detection of EMB (insert). The currents plotted are cathodic currents measured at −0.5 V and subtracted from current at 0 µM EMB. (<b>b</b>) Calibration curve for the PZA nanobiosensor and the CV for the detection of PZA (insert). The currents plotted are cathodic currents measured at −0.5 V and subtracted from current at 0 µM.</p> Full article ">
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 7241
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)
►▼ Show Figures

Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>(<b>A</b>) Impellers used for this study (from left to right): Rushton (six-blade turbine), three-paddle helix impeller, Brunswick Bioflo/CelliGen 115 bioreactor default propeller and small propeller (abbreviated as S. Propeller). (<b>B</b>) The impeller combinations used (from left to right): Rushton–paddles, propellers–paddles, and Rushton–propeller. (<b>C</b>) The 3/4 section view 3D CAD models of: Brunswick Bioflo/CelliGen 115 bioreactor (left); and transparent view (right).</p> Full article ">Figure 2
<p>(<b>A</b>) Boundary conditions for the power analysis using a Moving Reference Frame (MRF) scheme. (<b>B</b>) Boundary conditions for the flow patterns analysis, with the inlet and outlet of air and the Rigid Body Motion (RBM) scheme. In both cases, the yellow area corresponds to the boundary location of the rotation zone.</p> Full article ">Figure 3
<p>Mesh independence for: (<b>A</b>) power (●) and shear rate (■); and (<b>B</b>) computational time on Brunswick Bioflo/CelliGen 115 bioreactor.</p> Full article ">Figure 4
<p>(<b>A</b>) The first experimental process approximation for the calculation of power on Brunswick Bioflo/CelliGen 115 bioreactor using the impellers with inclined paddles. The curves for simulated power (●) and experimental data (■). (<b>B</b>) Analysis between the experimental and simulated data for the power of Brunswick Bioflo/CelliGen 115 bioreactor using impellers with inclined paddles.</p> Full article ">Figure 5
<p>Power number curve for the different regimes in Brunswick Bioflo/CelliGen 115 bioreactor using inclined: paddles impeller (<b>A</b>); Rushton impeller (<b>B</b>); small designed propeller (<b>C</b>); and default propeller (<b>D</b>). Curve for simulated power number, experimental data, and literature data [<a href="#B25-processes-08-00878" class="html-bibr">25</a>,<a href="#B26-processes-08-00878" class="html-bibr">26</a>]. (<b>E</b>) The simulated power number for different Re numbers using various impeller combinations can be observed: propeller–Rushton, Rushton–paddles, and paddles–propeller.</p> Full article ">Figure 6
<p>Flow patterns for Brunswick Bioflo/CelliGen 115 bioreactor at 250 RPM and 2.5 <math display="inline"><semantics> <mrow> <mi mathvariant="normal">l</mi> <mo> </mo> <msup> <mi>min</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> </semantics></math> for: (<b>A</b>) inclined paddles; (<b>B</b>) Rushton; and (<b>C</b>) propeller.</p> Full article ">Figure 7
<p>Shear rate values for each operation condition compared with the maximum shear rate of three different cell cultures.</p> Full article ">Figure A1
<p>Isometric view of inclined: Rushton impeller (<b>A</b>); Paddles impeller (<b>B</b>); Propeller impeller: default (<b>C</b>); Propeller impeller: small design (<b>D</b>); and Brunswick Bioflo/CelliGen 115 bioreactor vessel (<b>E</b>).</p> Full article ">Figure A2
<p>Glycerin viscosity as a function of the percentage of water.</p> Full article ">Figure A3
<p>Statistical analysis: (<b>top left</b>) the main effects of dissolved oxygen, where the velocity label corresponds with agitation velocity [RPM] and the airflow has units of [L/min]; (<b>top right</b>) interaction effects for oxygen dissolved; (<b>bottom left</b>) data homoscedasticity; and (<b>bottom right</b>) Pareto chart of the standardized effects.</p> Full article ">Figure A4
<p><math display="inline"><semantics> <mrow> <msub> <mi>k</mi> <mi>L</mi> </msub> <mi>a</mi> </mrow> </semantics></math> determination for one agitation configuration: (<b>A</b>) 2.5 <math display="inline"><semantics> <mrow> <mi mathvariant="normal">l</mi> <mo> </mo> <mi mathvariant="normal">m</mi> <mi mathvariant="normal">i</mi> <msup> <mi mathvariant="normal">n</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> </semantics></math> and 100 RPM; (<b>B</b>) 2.5 <math display="inline"><semantics> <mrow> <mi mathvariant="normal">l</mi> <mo> </mo> <mi mathvariant="normal">m</mi> <mi mathvariant="normal">i</mi> <msup> <mi mathvariant="normal">n</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> </semantics></math> and 250 RPM; (<b>C</b>) 5 <math display="inline"><semantics> <mrow> <mi mathvariant="normal">l</mi> <mo> </mo> <mi mathvariant="normal">m</mi> <mi mathvariant="normal">i</mi> <msup> <mi mathvariant="normal">n</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> </semantics></math> and 100 RPM; and (<b>D</b>) 5 <math display="inline"><semantics> <mrow> <mi mathvariant="normal">l</mi> <mo> </mo> <mi mathvariant="normal">m</mi> <mi mathvariant="normal">i</mi> <msup> <mi mathvariant="normal">n</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> </semantics></math> and 250 RPM.</p> Full article ">Figure A5
<p><math display="inline"><semantics> <mrow> <msub> <mi>k</mi> <mi>L</mi> </msub> <mi>a</mi> </mrow> </semantics></math> determination for two impeller configurations: (<b>A</b>) 2.5 <math display="inline"><semantics> <mrow> <mi mathvariant="normal">l</mi> <mo> </mo> <mi mathvariant="normal">m</mi> <mi mathvariant="normal">i</mi> <msup> <mi mathvariant="normal">n</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> </semantics></math> and 100 RPM; (<b>B</b>) 2.5 <math display="inline"><semantics> <mrow> <mi mathvariant="normal">l</mi> <mo> </mo> <mi mathvariant="normal">m</mi> <mi mathvariant="normal">i</mi> <msup> <mi mathvariant="normal">n</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> </semantics></math> and 250 RPM; (<b>C</b>) 5 <math display="inline"><semantics> <mrow> <mi mathvariant="normal">l</mi> <mo> </mo> <mi mathvariant="normal">m</mi> <mi mathvariant="normal">i</mi> <msup> <mi mathvariant="normal">n</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> </semantics></math> and 100 RPM; and (<b>D</b>) 5 <math display="inline"><semantics> <mrow> <mi mathvariant="normal">l</mi> <mo> </mo> <mi mathvariant="normal">m</mi> <mi mathvariant="normal">i</mi> <msup> <mi mathvariant="normal">n</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> </semantics></math> and 250 RPM.</p> Full article ">
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 2991
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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Figure 1

Figure 1
<p>Schematic diagrams of (<b>a</b>) oxygen blast furnace with top gas recycling (TGR-OBF) and (<b>b</b>) traditional blast furnace (TBF).</p> Full article ">Figure 2
<p>Geometric details of the models.</p> Full article ">Figure 3
<p>Effect of oxygen temperature: (<b>a</b>) coal burnout; (<b>b</b>) pure oxygen amount, Nm<sup>3</sup>/t∙HM.</p> Full article ">Figure 4
<p>Effect of oxygen temperature: (<b>a</b>) coal burnout at different positions; (<b>b</b>) coal particle temperature at different positions; (<b>c</b>) CO reaction rate.</p> Full article ">Figure 4 Cont.
<p>Effect of oxygen temperature: (<b>a</b>) coal burnout at different positions; (<b>b</b>) coal particle temperature at different positions; (<b>c</b>) CO reaction rate.</p> Full article ">Figure 5
<p>Effect of oxygen temperature on mass ratio (m/m<sub>0</sub>) of volatile matter.</p> Full article ">Figure 6
<p>Effect of oxygen temperature on m/m<sub>0</sub> of char.</p> Full article ">Figure 7
<p>Effect of oxygen temperature on oxygen distributions along Z = 0 plane.</p> Full article ">Figure 8
<p>Effect of oxygen temperature on average gas temperature along the centerline.</p> Full article ">Figure 9
<p>Effect of oxygen temperature on the final coal burnout.</p> Full article ">Figure 10
<p>Effect of oxygen temperature on (<b>a</b>) coal burnout at different positions; (<b>b</b>) CO combustion rate at different positions.</p> Full article ">
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 3578
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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Figure 1

Figure 1
<p>Schematic of the cross-sectional shape of the wire and the roll design during the flat rolling process with a (<b>a</b>) flat roll, (<b>b</b>) oval-grooved roll, and (<b>c</b>) cambered roll.</p> Full article ">Figure 2
<p>Detailed geometry and elements of the numerical modeling with a (<b>a</b>) flat roll, (<b>b</b>) oval-grooved roll with a radius of 10 mm, and (<b>c</b>) cambered roll with a radius of 10 mm.</p> Full article ">Figure 3
<p>(<b>a</b>) Photograph of the caliber-rolled TWIP steel wire in this experiment and the shape of the deformed wire based on the numerical simulation. (<b>b</b>) Comparison of the measured, simulated, theoretically derived <span class="html-italic">W</span> and <span class="html-italic">b</span> values as a function of the total reduction in height.</p> Full article ">Figure 4
<p>Contour maps of the effective strain and normal pressure of flat-rolled wires with a roll design and pass.</p> Full article ">Figure 5
<p>(<b>a</b>) Schematic showing the terminologies used in this study. Comparison of the effective strain profiles in (<b>b</b>) cross-sections of flat-rolled wires along the horizontal and vertical directions, and (<b>c</b>) the flat surface of a flat-rolled wire with the representative roll design.</p> Full article ">Figure 5 Cont.
<p>(<b>a</b>) Schematic showing the terminologies used in this study. Comparison of the effective strain profiles in (<b>b</b>) cross-sections of flat-rolled wires along the horizontal and vertical directions, and (<b>c</b>) the flat surface of a flat-rolled wire with the representative roll design.</p> Full article ">Figure 6
<p>Variations in (<b>a</b>) the maximum and minimum effective strains in the cross-sections of the flat-rolled wires and (<b>b</b>) the maximum and centered effective strains on the flat surface of a wire with <span class="html-italic">I</span><sub><span class="html-italic">RD</span></sub>.</p> Full article ">Figure 7
<p>Variations in the <span class="html-italic">b</span> and <span class="html-italic">W</span> values with <span class="html-italic">I</span><sub><span class="html-italic">RD</span></sub>.</p> Full article ">Figure 8
<p>Schematic description of the effective strain on the flat surface and shape of a flat-rolled wire with <span class="html-italic">I</span><sub><span class="html-italic">RD</span></sub>.</p> Full article ">
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 19 | Viewed by 8843
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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Figure 1

Figure 1
<p>Two-phase (air-water) flow loop in Pusan National University: (<b>a</b>) flow loop facilities; (<b>b</b>) 3D model.</p> Full article ">Figure 2
<p>Schematic of the test section.</p> Full article ">Figure 3
<p>Prototype and model of the test valve: (<b>a</b>) eight-inch ANSI B16.11—Class 2500# globe valve; (<b>b</b>) three-inch model globe valve.</p> Full article ">Figure 4
<p>Pressure distribution along the pipeline. (<b>a</b>) 10% opening. (<b>b</b>) 20% opening. (<b>c</b>) 30% opening. (<b>d</b>) 40% opening. (<b>e</b>) 50% opening. (<b>f</b>) 60% opening. (<b>g</b>) 70% opening. (<b>h</b>) 80% opening. (<b>i</b>) 90% opening. (<b>j</b>) 100% opening.</p> Full article ">Figure 4 Cont.
<p>Pressure distribution along the pipeline. (<b>a</b>) 10% opening. (<b>b</b>) 20% opening. (<b>c</b>) 30% opening. (<b>d</b>) 40% opening. (<b>e</b>) 50% opening. (<b>f</b>) 60% opening. (<b>g</b>) 70% opening. (<b>h</b>) 80% opening. (<b>i</b>) 90% opening. (<b>j</b>) 100% opening.</p> Full article ">Figure 4 Cont.
<p>Pressure distribution along the pipeline. (<b>a</b>) 10% opening. (<b>b</b>) 20% opening. (<b>c</b>) 30% opening. (<b>d</b>) 40% opening. (<b>e</b>) 50% opening. (<b>f</b>) 60% opening. (<b>g</b>) 70% opening. (<b>h</b>) 80% opening. (<b>i</b>) 90% opening. (<b>j</b>) 100% opening.</p> Full article ">Figure 5
<p>Pressure drop at the globe valve.</p> Full article ">Figure 6
<p>Comparison of pressure in the valve upstream: (<b>a</b>) 1000 RPM; (<b>b</b>) 1500 RPM; (<b>c</b>) 2000 RPM.</p> Full article ">Figure 7
<p>Comparison of pressure in the valve downstream: (<b>a</b>) 1000 RPM; (<b>b</b>) 1500 RPM; (<b>c</b>) 2000 RPM.</p> Full article ">Figure 8
<p>Comparison of pressure at the top to the bottom of the pipeline: (<b>a</b>) 1000 RPM; (<b>b</b>) 1500 RPM; (<b>c</b>) 2000 RPM.</p> Full article ">Figure 9
<p>Flow characteristic of the globe valve. (<b>a</b>) Inherent condition; (<b>b</b>) installed condition.</p> Full article ">Figure 10
<p>Comparison of the inherent and installed characteristics.</p> Full article ">Figure 11
<p>Flow coefficient in inherent condition: (<b>a</b>) with respect to valve opening; (<b>b</b>) with respect to the Reynolds number.</p> Full article ">Figure 12
<p>Flow coefficient in installed condition: (<b>a</b>) with respect to valve opening; (<b>b</b>) with respect to Renolds number.</p> Full article ">Figure 13
<p>Linearity and constant characteristics of flow coefficient with Reynolds number. (<b>a</b>) 10% opening. (<b>b</b>) 20% opening. (<b>c</b>) 30% opening. (<b>d</b>) 40% opening. (<b>e</b>) 50% opening. (<b>f</b>) 60% opening. (<b>g</b>) 70% opening. (<b>h</b>) 80% opening. (<b>i</b>) 90% opening. (<b>j</b>) 100% opening.</p> Full article ">Figure 13 Cont.
<p>Linearity and constant characteristics of flow coefficient with Reynolds number. (<b>a</b>) 10% opening. (<b>b</b>) 20% opening. (<b>c</b>) 30% opening. (<b>d</b>) 40% opening. (<b>e</b>) 50% opening. (<b>f</b>) 60% opening. (<b>g</b>) 70% opening. (<b>h</b>) 80% opening. (<b>i</b>) 90% opening. (<b>j</b>) 100% opening.</p> Full article ">Figure 14
<p>Flow coefficient characteristics with respect to valve opening: (<b>a</b>) slope of the linear trendlines of linear regions; (<b>b</b>) average flow coefficients of constant regions.</p> Full article ">
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 4501
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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Figure 1
<p>XRD diffractograms of the P-Containing V-Ti magnetite tailings.</p> Full article ">Figure 2
<p>Effect of different collectors on extracting phosphorous.</p> Full article ">Figure 3
<p>Effect of oxidized paraffin soap dosage on extracting phosphorous.</p> Full article ">Figure 4
<p>Effect of different depressants on extracting phosphorous.</p> Full article ">Figure 5
<p>Effect of carboxymethylcellulose dosage on extracting phosphorous.</p> Full article ">Figure 6
<p>Effect of grinding fineness on extracting phosphorous.</p> Full article ">Figure 7
<p>Effect of and flotation pulp pH on extracting phosphorous.</p> Full article ">Figure 8
<p>Effect of flotation concentration on extracting phosphorous.</p> Full article ">Figure 9
<p>Effect of different pH regulators on extracting phosphorous.</p> Full article ">Figure 10
<p>Time on flotation scavenging flowsheet.</p> Full article ">Figure 11
<p>Time on flotation cleaning flowsheet.</p> Full article ">Figure 12
<p>The whole direction flotation flowsheet of recovering phosphorous.</p> Full article ">Figure 13
<p>XRD diffractograms of the P–Containing V–Ti magnetite tailings.</p> Full article ">Figure 14
<p>SEM-EDS images of apatite (<b>a</b>), olivine (<b>b</b>), and feldspar (<b>c</b>).</p> Full article ">
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 6006
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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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>3-D high performance liquid chromatography (HPLC) chromatogram of <span class="html-italic">Andrographis paniculata</span> extract. The X-axis is retention time, Y-axis is wavelength, and Z-axis is absorbance unit.</p> Full article ">Figure 2
<p>The effects of <span class="html-italic">Andrographis paniculata</span> extract on weight-bearing of hind paw in the monosodium iodoacetate (MIA)-induced osteoarthritis model. (<b>A</b>) Weight-bearing distribution of MIA rats on 0, 3, 7, 10, 14, 17, 21, 24 days with 100 and 300 mg/kg <span class="html-italic">Andrographis paniculata</span> extract or 3 mg/kg indomethacin treatment and (<b>B</b>) area under the curve (AUC) were recorded using incapacitance meter tester. ### <span class="html-italic">p</span> &lt; 0.001 vs. sham, ** <span class="html-italic">p</span> &lt; 0.01 vs. control *** <span class="html-italic">p</span> &lt; 0.001 vs. control.</p> Full article ">Figure 3
<p>Photographic images of the knee joint cartilages of monosodium iodoacetate (MIA)-induced osteoarthritis rats. MIA rats were treated with indomethacin (3 mg/kg body weight) and <span class="html-italic">Andrographis paniculata</span> extract (100 and 300 mg/kg body weight).</p> Full article ">Figure 4
<p>The inhibitory effects of <span class="html-italic">A. paniculata</span> extract (APE) extract on serum inflammatory cytokine levels in monosodium iodoacetate (MIA) rats. Rats were treated with 100 and 300 mg/kg APE for 24 days, ** <span class="html-italic">p</span> &lt; 0.01 vs. control, *** <span class="html-italic">p</span> &lt; 0.001 vs. control by one-way ANOVA, Dunnett’s test.</p> Full article ">Figure 5
<p>Changes of matrix metalloproteinase (MMP) at knee joint cartilage tissue with <span class="html-italic">Andrographis paniculata</span> extract (100 and 300 mg/kg) treatment. mRNA expression of MMP-1, MMP-3, MMP-8, and MMP-13 (<b>A</b>–<b>D</b>) determined by quantitative Real Time PCR. (<b>E</b>–<b>I</b>) Protein expression of MMP-1, MMP-3, MMP-8, and MMP-13 measured with Western blot analysis. * <span class="html-italic">p</span> &lt; 0.05 vs. control, ** <span class="html-italic">p</span> &lt; 0.01 vs. control, *** <span class="html-italic">p</span> &lt; 0.001 vs. control by one-way ANOVA, Dunnett’s test.</p> Full article ">Figure 5 Cont.
<p>Changes of matrix metalloproteinase (MMP) at knee joint cartilage tissue with <span class="html-italic">Andrographis paniculata</span> extract (100 and 300 mg/kg) treatment. mRNA expression of MMP-1, MMP-3, MMP-8, and MMP-13 (<b>A</b>–<b>D</b>) determined by quantitative Real Time PCR. (<b>E</b>–<b>I</b>) Protein expression of MMP-1, MMP-3, MMP-8, and MMP-13 measured with Western blot analysis. * <span class="html-italic">p</span> &lt; 0.05 vs. control, ** <span class="html-italic">p</span> &lt; 0.01 vs. control, *** <span class="html-italic">p</span> &lt; 0.001 vs. control by one-way ANOVA, Dunnett’s test.</p> Full article ">Figure 6
<p>Effects of APE extract on writhing responses of acetic acid-induced Institute of Cancer Research (ICR) mice. After 30 min of oral administration, every mouse was intraperitoneally injected with 0.7% acetic acid before 10 min counting. The number of mice was 7–8 per group; ### <span class="html-italic">p</span> &lt; 0.001 vs. ibuprofen, * <span class="html-italic">p</span> &lt; 0.05 vs. control by one-way ANOVA, Dunnett’s test.</p> Full article ">Figure 7
<p>Effects of <span class="html-italic">Andrographis paniculata</span> extract on (<b>A</b>) cell viability and (<b>B</b>) LPS-induced NO generation and the expression of (<b>C</b>) IL-1β, (<b>D</b>) IL-6, (<b>E</b>) TNF-α, (<b>F</b>) iNOS, and (<b>G</b>) COX-2 in RAW264.7 cells. Cell were treated with <span class="html-italic">Andrographis paniculata</span> extract (10, 30, 100, 300, and 1000 μg/mL) and LPS (1 μg/mL) for 24 h. ### <span class="html-italic">p</span> &lt; 0.001 vs. sham, * <span class="html-italic">p</span> &lt; 0.05 vs. control, ** <span class="html-italic">p</span> &lt; 0.01 vs. control, *** <span class="html-italic">p</span> &lt; 0.001 vs. control by one-way ANOVA, Dunnett’s test.</p> Full article ">Figure 7 Cont.
<p>Effects of <span class="html-italic">Andrographis paniculata</span> extract on (<b>A</b>) cell viability and (<b>B</b>) LPS-induced NO generation and the expression of (<b>C</b>) IL-1β, (<b>D</b>) IL-6, (<b>E</b>) TNF-α, (<b>F</b>) iNOS, and (<b>G</b>) COX-2 in RAW264.7 cells. Cell were treated with <span class="html-italic">Andrographis paniculata</span> extract (10, 30, 100, 300, and 1000 μg/mL) and LPS (1 μg/mL) for 24 h. ### <span class="html-italic">p</span> &lt; 0.001 vs. sham, * <span class="html-italic">p</span> &lt; 0.05 vs. control, ** <span class="html-italic">p</span> &lt; 0.01 vs. control, *** <span class="html-italic">p</span> &lt; 0.001 vs. control by one-way ANOVA, Dunnett’s test.</p> Full article ">
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 4319
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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<p>Geometric model of fluid domain.</p> Full article ">Figure 2
<p>Geometric model of impeller and volute.</p> Full article ">Figure 3
<p>Mesh generation.</p> Full article ">Figure 4
<p>Grid dependence test.</p> Full article ">Figure 5
<p>Performance test installation of centrifugal fan.</p> Full article ">Figure 6
<p>Compare of aerodynamics performance between numerical simulations and experimental data at 1400 rpm. (<b>a</b>) Pressure-Volume flow rates, (<b>b</b>) Efficiency-Volume flow rates.</p> Full article ">Figure 7
<p>Pressure distributions of impeller and volute at z = 80 mm on the surface of revolution. (<b>a</b>) 0.15 Q<sub>d</sub>, (<b>b</b>) 0.3 Q<sub>d</sub>, (<b>c</b>) 0.5 Q<sub>d</sub>, (<b>d</b>) Q<sub>d</sub>.</p> Full article ">Figure 8
<p>Velocity distributions of impeller and volute at z = 80 mm on the surface of revolution. (<b>a</b>) 0.15 Q<sub>d</sub>, (<b>b</b>) 0.3 Q<sub>d</sub>, (<b>c</b>) 0.5 Q<sub>d</sub>, (<b>d</b>) Q<sub>d</sub>.</p> Full article ">Figure 9
<p>Streamline of impeller and volute at z = 80 mm on the surface of revolution. (<b>a</b>) 0.15 Q<sub>d</sub>, (<b>b</b>) 0.3 Q<sub>d</sub>, (<b>c</b>) 0.5 Q<sub>d</sub>, (<b>d</b>) Q<sub>d</sub>.</p> Full article ">Figure 10
<p>Streamline of impeller at z = 80 mm on the surface of revolution. (<b>a</b>) 0.15 Q<sub>d</sub>, (<b>b</b>) 0.3 Q<sub>d</sub>, (<b>c</b>) 0.5 Q<sub>d</sub>, (<b>d</b>) Q<sub>d</sub>.</p> Full article ">Figure 11
<p>Magnified image of individual channel. Leading edges of the two blades are marked as points 1 and 2, and the position of the suction surface near the exit is marked as point 3.</p> Full article ">Figure 12
<p>Three-dimensional streamline of impeller and volute. (<b>a</b>) 0.15 Q<sub>d</sub>, (<b>b</b>) 0.3 Q<sub>d</sub>, (<b>c</b>) 0.5 Q<sub>d</sub>, (<b>d</b>) Q<sub>d</sub>.</p> Full article ">Figure 13
<p>Three-dimensional streamline in the impeller. (<b>a</b>) 0.15 Q<sub>d</sub>, (<b>b</b>) 0.3 Q<sub>d</sub>, (<b>c</b>) 0.5 Q<sub>d</sub>, (<b>d</b>) Q<sub>d</sub>.</p> Full article ">Figure 14
<p>Streamline of impeller and volute on the meridian surface. (<b>a</b>) 0.15 Q<sub>d</sub>, (<b>b</b>) 0.3 Q<sub>d</sub>, (<b>c</b>) 0.5 Q<sub>d</sub>, (<b>d</b>) Q<sub>d</sub>.</p> Full article ">Figure 15
<p>Streamline of impeller on the circumferential surface. (<b>a</b>) 0.15 Q<sub>d</sub>, (<b>b</b>) 0.3 Q<sub>d</sub>, (<b>c</b>) 0.5 Q<sub>d</sub>, (<b>d</b>) Q<sub>d</sub>.</p> Full article ">Figure 16
<p>Streamline on the rotary surface of the impeller rotates one turn at 0.15 Q<sub>d</sub>. (<b>a</b>) 0.25 turn, (<b>b</b>) 0.5 turn, (<b>c</b>) 0.75 turn, (<b>d</b>) 1 turn.</p> Full article ">Figure 17
<p>Streamline on the rotary surface of the impeller changed with time evolution at 0.15Q<sub>d</sub>.</p> Full article ">Figure 18
<p>Monitory points.</p> Full article ">Figure 19
<p>Pressure fluctuations for the tongue at various working conditions.</p> Full article ">Figure 20
<p>Velocity fluctuations for the tongue at various working conditions.</p> Full article ">Figure 21
<p>Pressure fluctuations of the blade inside at various working conditions.</p> Full article ">Figure 22
<p>Velocity fluctuations of the blade inside at various working conditions.</p> Full article ">Figure 23
<p>Fluctuations for the tongue at various working condition. (<b>a</b>) Amplitude spectrum of pressure fluctuations, (<b>b</b>) Amplitude spectrum of velocity fluctuations.</p> Full article ">Figure 24
<p>Fluctuations of the blade inside at various working condition. (<b>a</b>) Amplitude spectrum of pressure fluctuations, (<b>b</b>) Amplitude spectrum of velocity fluctuations.</p> Full article ">
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 5689
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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<p>Experimental steps for preparing hypoallergenic liquid milk protein concentrate with functional values (antioxidant capacity, angiotensin converting enzyme inhibitory activity, and antibacterial activity).</p> Full article ">Figure 2
<p>Schematic diagram of the cross-flow membrane module.</p> Full article ">Figure 3
<p>Specific energy consumption and concentration of protein in the retentate side of membrane for different trans-membrane pressures (TMPs) and retention flow rates (RFRs) in static turbulence promoter-implemented filtration process. Results are represented by mean value with standard deviation (±values). In superscript, dissimilar alphabet represents the significant difference between results, evaluated by the Tukey’s post hoc method.</p> Full article ">Figure 4
<p>Time history of permeate flux without the static turbulence promoter (<b>A</b>) and with the static turbulence promoter (<b>B</b>).</p> Full article ">Figure 5
<p>Results of liquid chromatography-mass spectrometry; (<b>A</b>) UV chromatogram of proteins in concentrated milk, (<b>B</b>) total ion chromatogram of proteins in concentrated milk, (<b>C</b>) deconvoluted mass spectra of different proteins, peaks appear at retention time 5.4 min (<b>C1</b>), 5.6 min (<b>C2</b>), and 5.8 min (<b>C3</b>).</p> Full article ">Figure 6
<p>Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) image of ultra-heat-treated skimmed milk, milk with concentrated proteins and milk with concentrated proteins after enzyme treatment; lane 1: marker protein, lane 2: standard casein, lane 3: standard α-lactalbumin and β-lactoglobulin, lane 4: ultra-heat-treated skimmed milk, lane 5: concentrated ultra-heat-treated skimmed milk, lane 6: concentrated liquid milk protein treated with 0.008 g L<sup>−1</sup> of trypsin, lane 7: concentrated liquid milk protein treated with 0.016 g L<sup>−1</sup> of trypsin, lane 8:concentrated liquid milk protein treated with 0.032 g L<sup>−1</sup> of trypsin, lane 9: concentrated liquid milk protein treated with 0.064 g L<sup>−1</sup> of trypsin.</p> Full article ">Figure 7
<p>Antioxidant capacity of ultra-heat-treated skimmed milk, milk with concentrated proteins, and milk with concentrated proteins after enzyme treatment. Results are represented by mean value with standard deviation (±values). In superscript, dissimilar alphabet represents the significant difference between results, evaluated by the Tukey’s post hoc method.</p> Full article ">Figure 8
<p>Angiotensin converting enzyme (ACE)-inhibitory activity of ultra-heat-treated skimmed milk and milk with concentrated proteins (<b>A</b>), and values of IC<sub>50</sub> in milk with concentrated proteins after enzyme treatment (<b>B</b>). Results are represented by mean value with standard deviation (±values). In superscript, dissimilar alphabet represents the significant difference between results, evaluated by the Tukey’s post hoc method.</p> Full article ">Figure 9
<p>Antibacterial activity of milk with concentrated proteins after enzyme treatment. Results are represented by mean value with standard deviation (±values). Superscript dissimilar alphabet represents the significant difference between results, evaluated by the Tukey’s post hoc method.</p> Full article ">Figure 10
<p>Immunoblot of ultra-heat-treated skimmed milk, milk with concentrated proteins and milk with concentrated proteins after enzyme treatment; lane 1: marker protein, lane 2: standard casein, lane 3: standard α-lactalbumin and β-lactoglobulin, lane 4: ultra-heat-treated skimmed milk, lane 5: concentrated ultra-heat-treated skimmed milk, lane 6: concentrated liquid milk protein treated with 0.008 g·L<sup>−1</sup> of trypsin, lane 7: concentrated liquid milk protein treated with 0.016 g·L<sup>−1</sup> of trypsin, lane 8: concentrated liquid milk protein treated with 0.032 g·L<sup>−1</sup> of trypsin, lane 9: concentrated liquid milk protein treated with 0.064 g·L<sup>−1</sup> of trypsin.</p> Full article ">
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 9875
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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<p>Chemical structure of analyzed compounds.</p> Full article ">Figure 2
<p>Example densitogram registered for a solution of a mixture of standards at 254 nm.</p> Full article ">Figure 3
<p>Overlay UV absorption spectra of standards registered directly from the densitogram.</p> Full article ">
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 3347
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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<p>In-house XCT-1600 HR µ-CT; (<b>1</b>) X-ray tube; (<b>2</b>) Fixed freeze-drying stage; (<b>3</b>) CCD-11000XR detector; (<b>4</b>) Stage-Connection; (<b>5</b>) Winding support.</p> Full article ">Figure 2
<p>Isometric and sectional view of the developed freeze-drying stage for µ-CT measurements; (<b>1</b>) cap; (<b>2</b>) sample holder; (<b>3</b>) PT1000 bore hole; (<b>4</b>) vacuum chamber with thread to mount the cap; (<b>5</b>) seal; (<b>6</b>) Swagelok connecter; (<b>7</b>) seal; (<b>8</b>) electrical housing; and (<b>9</b>) thermoelectric cooler; (<b>10</b>) heat sink; (<b>11</b>) support plate.</p> Full article ">Figure 3
<p><b>Left</b>: Particle sample on the sample holder; <b>Right</b>: Cylindrical cup-attachment for packed beds and liquids.</p> Full article ">Figure 4
<p>Partly dried and dried sectional view of a 20% (w/w) maltodextrin particle. Before (<b>Left</b>) and after (<b>Right</b>) a structural collapse.</p> Full article ">Figure 5
<p>Sectional view of a dried 20% (w/w) sucrose particle.</p> Full article ">Figure 6
<p>Sectional view of a dried 5% (w/w) sucrose solution.</p> Full article ">Figure 7
<p><b>Left</b>: Coagulation of chicken protein (radiographic image); <b>Right</b>: Slice of a partly dried chicken protein particle.</p> Full article ">
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 17 | Viewed by 7312
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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<p>Palm-oil-based integrated biorefinery concept [<a href="#B55-processes-08-00868" class="html-bibr">55</a>].</p> Full article ">Figure 2
<p>Methodology for identification of optimal empty fruit bunch (EFB)-based biorefinery configuration.</p> Full article ">Figure 3
<p>Schematic of the integrated biorefinery from the empty fruit bunch (EFB).</p> Full article ">Figure 4
<p>Schematic of alternate Pareto-optimal solutions for the integrated biorefinery.</p> Full article ">Figure 5
<p>Pareto-optimal front for profit versus global warming potential.</p> Full article ">Figure 6
<p>The biorefinery configuration of the optimal point S1 for profit and global warming potential objectives.</p> Full article ">Figure 7
<p>The biorefinery configuration of the optimal point S3 for profit and global warming potential objectives.</p> Full article ">Figure 8
<p>Pareto-optimal fronts for (<b>a</b>) profit versus fire explosion damage index and (<b>b</b>) profit versus toxicity damage index.</p> Full article ">Figure 9
<p>The optimal biorefinery configuration of the optimal point S1 for profit and fire explosion damage index in <a href="#processes-08-00868-f008" class="html-fig">Figure 8</a>a.</p> Full article ">Figure 10
<p>The optimal biorefinery configuration of the optimal point S3 for profit and fire explosion damage index in <a href="#processes-08-00868-f008" class="html-fig">Figure 8</a>a.</p> Full article ">Figure 11
<p>The optimal biorefinery configuration of the optimal point S1 for profit and toxicity damage index in <a href="#processes-08-00868-f008" class="html-fig">Figure 8</a>b.</p> Full article ">Figure 12
<p>The optimal biorefinery configuration of the optimal point S3 for profit and toxicity damage index in <a href="#processes-08-00868-f008" class="html-fig">Figure 8</a>b.</p> Full article ">Figure 13
<p>Pareto-optimal fronts for (<b>a</b>) profit, global warming potential, and fire explosion damage index and (<b>b</b>) profit, global warming potential, and toxicity damage index.</p> Full article ">Figure 14
<p>The optimal biorefinery configuration for simultaneously maximizing annual profit and minimizing global warming potential, fire explosion damage index, and toxicity damage index.</p> Full article ">
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 2967
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 4962
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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<p>Overview of different modeling depths with increasing detail [<a href="#B18-processes-08-00866" class="html-bibr">18</a>].</p> Full article ">Figure 2
<p>Model approach for solid-liquid extraction [<a href="#B15-processes-08-00866" class="html-bibr">15</a>].</p> Full article ">Figure 3
<p>Solid-liquid equilibria according to Henry (<b>A</b>), Freundlich (<b>B</b>), Langmuir (<b>C</b>), and Langmuir with saturation concentration (<b>D</b>).</p> Full article ">Figure 4
<p>Relevant parameters for modeling of extraction processes.</p> Full article ">Figure 5
<p>Ishikawa diagram for the considered solid-liquid extraction process.</p> Full article ">Figure 6
<p>Qualitative failure mode effect analysis (FMEA) for the considered solid-liquid extraction process. The broken lines represent the impact on product quality based on the average value. Risk categories are colored according to the category (red = process, green = material, grey = equipment).</p> Full article ">Figure 7
<p>Scaling of laboratory equipment from production scale [<a href="#B20-processes-08-00866" class="html-bibr">20</a>,<a href="#B32-processes-08-00866" class="html-bibr">32</a>].</p> Full article ">Figure 8
<p>Multi-column extraction apparatus for automated process characterization of process sequences consisting of maceration and percolation stages.</p> Full article ">Figure 9
<p>Automated sampling reel for sample collection.</p> Full article ">Figure 10
<p>Step function of the production equipment.</p> Full article ">Figure 11
<p>Determination of void volume by short-cut method.</p> Full article ">Figure 12
<p>Residence time distribution with column and packing.</p> Full article ">Figure 13
<p>Direct comparison between the residence time distribution between production and laboratory scale.</p> Full article ">Figure 14
<p>Concentration profiles for different limitations in a maceration process (left) and a percolation process (right).</p> Full article ">Figure 15
<p>Profile of extracted mass for the reference process.</p> Full article ">Figure 16
<p>Design spaces for component 1–4 for varying flow rates and particle sizes.</p> Full article ">Figure 17
<p>Comparison of the reference process (right) and a single step percolation (left) with constant product quality.</p> Full article ">Figure 18
<p>Comparison of the reference process (right) and a maceration (left) with constant product quality.</p> Full article ">Figure 19
<p>Comparison of the reference process (right) and a small-scale percolation (left) with constant product quality.</p> Full article ">Figure 20
<p>Scheduling for a continuous extraction process with a two-column concept.</p> Full article ">Figure 21
<p>Comparison of the solvent ratio (left) and product concentration (right) for the examined process alternatives.</p> Full article ">Figure 22
<p>Comparison of the space-time yield for the examined process alternatives.</p> Full article ">Figure 23
<p>Potential of different extraction methods in handling two basic mass transfer limitations and overview of different characterized plant systems.</p> Full article ">Figure 24
<p>Equivalent flowsheet for a carousel extractor.</p> Full article ">
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 5565
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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<p>Cellink bioprinting conical tips. From left to right: 20, 22, and 25G. Reproduced with permission from Cellink<sup>®</sup>.</p> Full article ">Figure 2
<p>Representation of models’ geometry, in millimeters, based on real measures of a commercial conical tip where X = 0.30, 0.20, and 0.13 mm for 20, 22, and 25G, respectively (<b>right</b>). Representation of bioink domain (light grey) and air domain (dark grey) with all boundary conditions (<b>left</b>).</p> Full article ">Figure 3
<p>Cellink Bioink rheological data. Reproduced with permission of Cellink<sup>®</sup>.</p> Full article ">Figure 4
<p>Maximum outlet pressure for 20, 22, and 25G conical tips using Cellink Bioink at 15, 25, and 37 °C.</p> Full article ">Figure 5
<p>Total extruded volume for 20, 22, and 22G conical tips using Cellink Bioink at 15, 25, and 37 °C.</p> Full article ">Figure 6
<p>Volume fraction of Cellink Bioink. (<b>A</b>) 20G at 25 °C in t = 3.14 s, (<b>B</b>) 20G at 37 °C in t = 2.31 s, (<b>C</b>) 22G at 25 °C in t = 10.00 s and (<b>D</b>) 22G at 37 °C in t = 6.86 s. Blue color represents Cellink Bioink and white color represents the air.</p> Full article ">Figure 7
<p>Maximum outlet velocity of 20G, 22G, and 25G conical tips using Cellink Bioink at 15, 25, and 37 °C.</p> Full article ">Figure 8
<p>Maximum shear stress of 20, 22, and 25G conical tips using Cellink Bioink at 15, 25, and 37 °C.</p> Full article ">Figure 9
<p>Shear stress distribution (Pa) at 37 °C.</p> Full article ">
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 5596
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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<p>Six different gearbox product types.</p> Full article ">Figure 2
<p>Assembly diagram for SAN gearbox type (RFID—radio-frequency identification).</p> Full article ">Figure 3
<p>Instruction page for two assembly steps of SAN gearbox type.</p> Full article ">Figure 4
<p>Assembly line balancing procedure.</p> Full article ">Figure 5
<p>Gearbox assembly line setup for the first iteration (LCD—Liquid Crystal Display, WS1—workstation 1, WS2—workstation 2).</p> Full article ">Figure 6
<p>Process times and standard deviations in the first experimentation iteration.</p> Full article ">Figure 7
<p>Radio-frequency identification (RFID) antenna, Raspberry Pi 3B+ (RPi), pushbuttons, and different appearances of touch Liquid Crystal Display (LCD).</p> Full article ">Figure 8
<p>Process times and standard deviations in the second experimentation iteration.</p> Full article ">Figure 9
<p>Process times and standard deviations in the third experimentation iteration.</p> Full article ">
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 19 | Viewed by 4341
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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<p>Materials used in the experiment: (<b>a</b>) sulfur pulp; (<b>b</b>) carbide lime.</p> Full article ">Figure 2
<p>pH<sub>KCl</sub> value of soil during the experiment: (<b>a</b>) unlimed soil; (<b>b</b>) limed soil. C: control soil (with no additions); S-I: soil with the addition of sulfur pulp (sulfur dose: I); S-II: soil with the addition of sulfur pulp (sulfur dose: II); S-III: soil with the addition of sulfur pulp (sulfur dose: III); S-IV: soil with the addition of sulfur pulp (sulfur dose: IV); Sas-II: soil with the addition of ammonium sulfate (sulfur dose: II).</p> Full article ">Figure 3
<p>Principal component analysis (PCA) showing relationships between the examined parameters, incubation time and sulfur doses: (<b>a</b>) principal components PC1 and PC2 for unlimed soil; (<b>b</b>) principal components PC1 and PC3 for unlimed soil; (<b>c</b>) principal components PC2 and PC3 for unlimed soil; (<b>d</b>) principal components PC1 and PC2 for limed soil; (<b>e</b>) principal components PC1 and PC3 for limed soil; (<b>f</b>) principal components PC2 and PC3 for limed soil.</p> Full article ">
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 3939
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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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>A simplified model of the SO<sub>2</sub> absorption process.</p> Full article ">Figure 2
<p>3D Computer Aided Design (CAD) model of the scrubber.</p> Full article ">Figure 3
<p>Simplified scrubber meshes.</p> Full article ">Figure 4
<p>Pressure map inside the scrubber.</p> Full article ">Figure 5
<p>Velocity map inside the scrubber.</p> Full article ">Figure 6
<p>Speed vectors contour and streamlines inside the scrubber.</p> Full article ">Figure 7
<p>Temperature contours inside the scrubber.</p> Full article ">Figure 8
<p>Velocity and temperature for the preferred planes along the flow direction.</p> Full article ">Figure 9
<p>3D distribution of the spray droplets.</p> Full article ">Figure 10
<p>Pressure for the preferred planes along the flow direction.</p> Full article ">Figure 11
<p>Temperature distribution of the scrubber wall.</p> Full article ">Figure 12
<p>Distribution of the droplets inside the scrubber (Z<sub>A</sub> = 2.2 m, Z<sub>B</sub> = 3.92 m).</p> Full article ">Figure 13
<p>Distribution of the spray nozzles.</p> Full article ">Figure 14
<p>Comparison of the number of droplets that hitting the wall.</p> Full article ">Figure 15
<p>Distribution of the spray droplets.</p> Full article ">Figure 16
<p>Contour of the outlet temperature.</p> Full article ">Figure 17
<p>Nozzle photo and injection direction.</p> Full article ">Figure 18
<p>3D distribution of the droplets.</p> Full article ">Figure 18 Cont.
<p>3D distribution of the droplets.</p> Full article ">Figure 19
<p>Average temperature inside the scrubber.</p> Full article ">Figure 20
<p>3D distribution of the droplets.</p> Full article ">Figure 21
<p>Pressure map inside the scrubber.</p> Full article ">
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 3130
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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<p>Exploded schematic view and photograph of a single chamber the air-cathode microbial fuel cell (MFC) with an end frame for controlling relative humidity.</p> Full article ">Figure 2
<p>Voltage generation from a single chamber air cathode MFC at different relative humidity (RH: 30 ± 2%, 50 ± 2% and 90 ± 2%) conditions with (<b>a</b>) Nafion 117 and (<b>b</b>) PP80 as a separator.</p> Full article ">Figure 3
<p>I-V and polarization curve of a single chamber air cathode MFC using (<b>a</b>) Nafion 117 and (<b>c</b>) PP80 at different relative humidity conditions. Variation in individual electrode potentials in relation to current densities by using (<b>b</b>) Nafion 117 and (<b>d</b>) PP80 as a separator.</p> Full article ">Figure 4
<p>Cyclic voltammogram analysis of air-cathode MFCs with Nafion 117 (<b>a</b>) and PP80 (<b>b</b>) at different relative humidity (RH).</p> Full article ">Figure 5
<p>Tafel analysis derived from the voltametric profiles during forward and reverse scans of Nafion 117 (<b>a</b>) and PP80 (<b>b</b>) at different relative humidity (RH).</p> Full article ">Figure 6
<p>Dissolved oxygen levels noted in a single chamber air-cathode MFC with Nafion 117 (<b>a</b>) and PP80 (<b>b</b>) at different relative humidity (RH) conditions.</p> Full article ">
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 31 | Viewed by 4198
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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Figure 1
<p>Experimental IR spectra of lignin samples. The abbreviations of lignin fractionated from pine sawdust (PL), cotton stalks (CL), sweet sorghum bagasse (SSL), spruce bark with (SBAL) and without acid addition (SBNL) were used.</p> Full article ">Figure 2
<p>(<b>a</b>–<b>c</b>) DTG curves of lignin samples in 100% N<math display="inline"><semantics> <msub> <mrow/> <mn>2</mn> </msub> </semantics></math>, O<math display="inline"><semantics> <msub> <mrow/> <mn>2</mn> </msub> </semantics></math> (5% volume fraction O<math display="inline"><semantics> <msub> <mrow/> <mn>2</mn> </msub> </semantics></math> + 95% volume fraction N<math display="inline"><semantics> <msub> <mrow/> <mn>2</mn> </msub> </semantics></math>) and CO<math display="inline"><semantics> <msub> <mrow/> <mn>2</mn> </msub> </semantics></math> (20% volume fraction CO<math display="inline"><semantics> <msub> <mrow/> <mn>2</mn> </msub> </semantics></math> + 80% volume fraction N<math display="inline"><semantics> <msub> <mrow/> <mn>2</mn> </msub> </semantics></math>). The abbreviations of lignin fractionated from pine sawdust (PL), cotton stalks (CL), sweet sorghum bagasse (SSL), spruce bark with (SBAL) and without acid addition (SBNL) were used.</p> Full article ">
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 3061
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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<p>Schematic illustration of the preparation of biocomposite poly(propylene oxide) (PPO) nanoparticles with the PPO-binding peptide in an aqueous solution.</p> Full article ">Figure 2
<p>Transmission electron microscopy (TEM) images of the objects in the supernatants after sonication and subsequent centrifugation. (<b>a</b>) Biocomposite PPO nanoparticles prepared in the presence of PPO-binding peptide. (<b>b</b>) PPO aggregates prepared in the absence of peptides. (<b>c</b>) PPO aggregates prepared in the presence of the naphthalene-binding peptide. (<b>d</b>) Aggregates of the PPO-binding peptide.</p> Full article ">Figure 3
<p>Atomic force microscopy (AFM) observation of the biocomposite nanoparticles using PPO and PPO-binding peptides. (<b>a</b>) Height image of biocomposite PPO nanoparticles prepared in the presence of the PPO-binding peptide. A representative cross-sectional analysis of the biocomposite nanoparticles is shown in the figure. (<b>b</b>) Phase image of biocomposite PPO nanoparticles observed in another position to (<b>a</b>).</p> Full article ">Figure 4
<p>Time-dependent dynamic light scattering (DLS) measurements of the biocomposite nanoparticles composed of PPO and PPO-binding peptides.</p> Full article ">Figure 5
<p>Structural comparison of PPO and PPO-binding peptides obtained from molecular mechanics (MM) calculations. Grey, white, blue, and red colors represent carbon, hydrogen, nitrogen, and oxygen molecules, respectively.</p> Full article ">
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 4050
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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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>The visual interpretation of Lipinski’s rule of five criteria.</p> Full article ">Figure 2
<p>Structure of 1,2,3-triazole-dipyridothiazine hybrids (<b>1–10</b>) and prothipendyl (<b>11</b>).</p> Full article ">Figure 3
<p>Graphical visualization of calculated log<span class="html-italic">P</span> values (using VCCLAB models) of the tested compounds with a comparison to log<span class="html-italic">P<sub>TLC</sub></span>.</p> Full article ">Figure 4
<p>Graphical visualization of the calculated log<span class="html-italic">P</span> values (using SwissADME models) of the tested compounds with a comparison to log<span class="html-italic">P<sub>TLC</sub></span>.</p> Full article ">
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 16676
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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Graphical abstract
Full article ">Figure 1
<p>Krona chart of the proximate composition of black soldier fly larvae (BSFL) (adapted from [<a href="#B11-processes-08-00857" class="html-bibr">11</a>]).</p> Full article ">Figure 2
<p>Food wastes: Global and European context. (<b>a</b>) global fruit and vegetable losses (<b>b</b>) food losses in different categories across Europe (adapted from [<a href="#B13-processes-08-00857" class="html-bibr">13</a>]).</p> Full article ">Figure 3
<p>Insect bioconversion: material balance overview.</p> Full article ">Figure 4
<p>Nutrition upcycling from waste streams and circular economy.</p> Full article ">Figure 5
<p>Unit operations in wet and dry fractionation of BSFL: An industrial-scale purview. (<b>A</b>) wet fractionation scheme with enzyme application (<b>B</b>) wet fractionation scheme with juice press (<b>C</b>) converntional dry fractionation (<b>D</b>) dry fractionation with an electrostatic separator.</p> Full article ">Figure 6
<p>Breakdown of unitary operations in industrial patents.</p> Full article ">Figure 7
<p>Constituents retrievable via BSFL biorefinery.</p> Full article ">Figure 8
<p>Flow chart of BSFL oil, protein, biodiesel and chitin extraction.</p> Full article ">Figure 9
<p>Structures of select chemical constituents present in BSFL.</p> Full article ">Figure 10
<p>General overview of verticals in BSF rearing and processing.</p> Full article ">Figure 11
<p>Factors influencing BSFL growth.</p> Full article ">Figure 12
<p>Substrates approved for BSF rearing (adapted from the International Platform of Insects for Food and Feed (IPIFF)).</p> Full article ">Figure 13
<p>Strengths, weaknesses, opportunities, and threats (SWOT) analysis of BSFL rearing and processing.</p> Full article ">Figure 14
<p>Insect rearing: Sustainable development goals perspective.</p> Full article ">
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 4665
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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<p>The conversion of ε-caprolactam in bulk (melt) AROP with and without quenching as a function of polymerization time (CPL/C10/C20 = 93.6/3.2/3.2 wt%, 170 °C reaction temperature).</p> Full article ">Figure 2
<p>The Gel permeation chromatography (GPC) chromatograms of Polyamide 6 samples prepared by bulk (melt) AROP of ε-caprolactam with different polymerization times with and without quenching (without quenching is assigned by star (*); CPL/C10/C20 = 93.6/3.2/3.2 wt%, 170 °C reaction temperature).</p> Full article ">Figure 3
<p>The average molecular weights (M<sub>n</sub>) (<b>a</b>) and the polydispersity index (PDI = M<sub>w</sub>/M<sub>n</sub>) (<b>b</b>) of Polyamide 6 samples prepared by bulk (melt) AROP of ε-caprolactam with and without quenching as a function of polymerization time (CPL/C10/C20 = 93.6/3.2/3.2 wt%, 170 °C reaction temperature).</p> Full article ">Figure 4
<p>The average molecular weights (M<sub>n</sub>) (<b>a</b>) and the polydispersity index (PDI = M<sub>w</sub>/M<sub>n</sub>) (<b>b</b>) of Polyamide 6 samples prepared by AROP of ε-caprolactam with and without quenching as a function of monomer conversion (CPL/C10/C20 = 93.6/3.2/3.2 wt%, 170 °C reaction temperature).</p> Full article ">Scheme 1
<p>Anionic ring-opening polymerization (AROP) of ε-caprolactam (CPL) by the lactamate–carbamoylcaprolactam initiator–activator combination.</p> Full article ">Scheme 2
<p>Reactions of the caprolactamate monomeric (top) and propagating polymeric (bottom) amide anions with an amide group in the polymer chain to form in-chain reactive amide anions.</p> Full article ">Scheme 3
<p>Possible branching reactions in the course of the anionic ring-opening polymerization of ε-caprolactam.</p> Full article ">
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 3136
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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<p>Schematic of modular model predictive control layer on top of an existing feedback controller.</p> Full article ">Figure 2
<p>Time series of the output, input, and perturbation input trajectories. The thin solid (blue) lines denote the original closed-loop with the existing controller. The thick (red) solid lines represent the response of the closed-loop with the modular MPC with the preview measurement, whilst the dashed lines denote the original closed-loop with the proposed MPC module with the preview and constraint knowledge.</p> Full article ">Figure 2 Cont.
<p>Time series of the output, input, and perturbation input trajectories. The thin solid (blue) lines denote the original closed-loop with the existing controller. The thick (red) solid lines represent the response of the closed-loop with the modular MPC with the preview measurement, whilst the dashed lines denote the original closed-loop with the proposed MPC module with the preview and constraint knowledge.</p> Full article ">Figure 3
<p>Time-series of predictions and closed-loop trajectory of the perturbation input. Four diagrams at a different time, showing that the predicted perturbation sequence (grey solid line) is consistent with the actual input trajectory (dash line).</p> Full article ">
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 2300
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 24 | Viewed by 3833
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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<p>Mechanical structure of the traditional 2D piston pump.</p> Full article ">Figure 2
<p>Mechanical structure of the high-speed 2D piston pump [<a href="#B17-processes-08-00853" class="html-bibr">17</a>].</p> Full article ">Figure 3
<p>Critical structures of the high-speed 2D piston pump [<a href="#B17-processes-08-00853" class="html-bibr">17</a>]. (<b>a</b>) Driving set; (<b>b</b>) balancing set; (<b>c</b>) left roller set.</p> Full article ">Figure 4
<p>Theoretical curves of the high-speed 2D piston pump [<a href="#B17-processes-08-00853" class="html-bibr">17</a>]. (<b>a</b>) The curves of the reciprocating motions; (<b>b</b>) the curves of the output flow rates.</p> Full article ">Figure 5
<p>Force analysis of the driving set while rotating from 0 degrees to 45 degrees.</p> Full article ">Figure 6
<p>Force analysis of the cone rollers on the left driving set when the driving set rotates from 0 degrees to 45 degrees. (<b>a</b>) Axial component force of the supporting force on the cone roller; (<b>b</b>) force analysis of the cone rollers on the guiding rail.</p> Full article ">Figure 7
<p>Force analysis of the driving set when rotating from 45 degrees to 90 degrees.</p> Full article ">Figure 8
<p>Force analysis of the driving set while rotating from 45 degrees to 90 degrees when the load pressure is low.</p> Full article ">Figure 9
<p>Force analysis of the cone rollers on the right driving set when it rotates from 45 degrees to 90 degrees.</p> Full article ">Figure 10
<p>Resistance torque caused by the shearing flow during rotation.</p> Full article ">Figure 11
<p>The input torques of the driving set at different rotational speeds and at a load pressure of 8 MPa.</p> Full article ">Figure 12
<p>The input torques of the driving set at different masses.</p> Full article ">Figure 13
<p>Theoretical mechanical efficiencies at different rotational speeds. (<b>a</b>) Without considering the viscosity damping and oil stirring losses; (<b>b</b>) with considering the viscosity damping and oil stirring losses.</p> Full article ">Figure 14
<p>Input torque distribution of the driving set under different load pressures at 5000 rpm. (<b>a</b>) Normal load pressures; (<b>b</b>) relatively low load pressures.</p> Full article ">Figure 15
<p>Theoretical mechanical efficiency under different load pressures at 5000 rpm.</p> Full article ">Figure 16
<p>Experimental schematic diagram.</p> Full article ">Figure 17
<p>Comparison between the experimental and analytical results of the high-speed 2D piston pump. (<b>a</b>) At 1000 rpm; (<b>b</b>) at 5000 rpm.</p> Full article ">Figure 18
<p>Comparison between the experimental and analytical results at different rolling friction coefficients at 5000 rpm.</p> Full article ">
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 3077
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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<p>Various dyes molecular structures.</p> Full article ">Figure 2
<p>Effect of ratios on adsorption capacity by not washed (NW) and washed (W) digestate adsorbents towards various dyes removal. Ratios: (W<sub>adsorbents</sub> (g): C<sub>dyes</sub> (mg/L)). (<b>a</b>) Methylene Blue (MB); (<b>b</b>) Direct yellow 27 (DY27); (<b>c</b>) Acid Red 66 (AR66); (<b>d</b>) Reactive Violet 5 (RV5); (<b>e</b>) Reactive Black 5 (RB5).</p> Full article ">Figure 2 Cont.
<p>Effect of ratios on adsorption capacity by not washed (NW) and washed (W) digestate adsorbents towards various dyes removal. Ratios: (W<sub>adsorbents</sub> (g): C<sub>dyes</sub> (mg/L)). (<b>a</b>) Methylene Blue (MB); (<b>b</b>) Direct yellow 27 (DY27); (<b>c</b>) Acid Red 66 (AR66); (<b>d</b>) Reactive Violet 5 (RV5); (<b>e</b>) Reactive Black 5 (RB5).</p> Full article ">Figure 2 Cont.
<p>Effect of ratios on adsorption capacity by not washed (NW) and washed (W) digestate adsorbents towards various dyes removal. Ratios: (W<sub>adsorbents</sub> (g): C<sub>dyes</sub> (mg/L)). (<b>a</b>) Methylene Blue (MB); (<b>b</b>) Direct yellow 27 (DY27); (<b>c</b>) Acid Red 66 (AR66); (<b>d</b>) Reactive Violet 5 (RV5); (<b>e</b>) Reactive Black 5 (RB5).</p> Full article ">Figure 3
<p>Adsorption capacity of various dyes onto digestate adsorbents. Ratio 1:50 (W<sub>adsorbents</sub> = 0.05 g: Cdyes = 50 mg/L). (<b>a</b>) Not washed digestate adsorbent, (<b>b</b>) washed digestate adsorbent.</p> Full article ">Figure 4
<p>Adsorption capacity under different ratio at 48 h for not washed and washed digestate adsorbent removal of various dyes. (<b>a</b>) MB; (<b>b</b>) DY27; (<b>c</b>) AR66; (<b>d</b>) RV5; (<b>e</b>) RB5.</p> Full article ">
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 3618
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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<p>Principles of the unscented transformation. (<b>a</b>) Confidence region of the uncertain parameters (<b>b</b>) The image set of the nonlinear function <math display="inline"><semantics> <mi mathvariant="bold-italic">n</mi> </semantics></math>.</p> Full article ">Figure 2
<p>Scenario tree of the multi-stage NMPC.</p> Full article ">Figure 3
<p>Comparison between multi-stage NMPC based on the vertex approximation and multi-stage NMPC based on the box over-approximation of the reachable states set. (<b>a</b>) Confidence region of the uncertain parameters (<b>b</b>) Predictions and the reachable set for MS-VA NMPC. (<b>c</b>) Predictions, reachable set and over-approximation of the reachable set for MS-SB NMPC.</p> Full article ">Figure 4
<p>Comparison between multi-stage NMPC based on the vertex approximation, multi-stage NMPC based on the box over-approximation of the set of reachable states, multi-stage NMPC based on the box over-approximation of the reachable set of the constraint function. (<b>a</b>) Confidence region of the uncertain parameters. (<b>b</b>) Constraint space when the system is controlled using MS-VA NMPC. ● represents the constraint function values obtained for the nodes in the scenario tree. (<b>c</b>) Constraint space when the system is controlled using MS-SB NMPC. <span style="color:#0000FF">■</span> represents the constraint function value obtained using the vertices of the box over-approximation of the set of reachable states along with its state mean Equation (10f). (<b>d</b>) Constraint space when the system is controlled using MS-CB NMPC.</p> Full article ">Figure 5
<p>Input feed, jacket cooling power, reactor temperature, and moles of product C obtained using different NMPC strategies in the presence of measurement noise. Left figure: The plant is controlled using the non-adaptive approaches explained in <a href="#sec3-processes-08-00851" class="html-sec">Section 3</a>, Right figure: The plant is controlled using the adaptive approaches explained in <a href="#sec4-processes-08-00851" class="html-sec">Section 4</a>. The true plant parameters are assumed to be the nominal parameters. NMPC (no mismatch)—the plant model and the simulation model are identical.</p> Full article ">Figure 6
<p>Reactor temperature, input feed, and jacket cooling power predicted in the scenario tree of the MS NMPC optimization problem solved at time <math display="inline"><semantics> <mrow> <mi>t</mi> <mo>=</mo> <mn>0.15</mn> <mspace width="3.33333pt"/> <mi mathvariant="normal">h</mi> </mrow> </semantics></math>. The magenta line (<span style="color:#FF00FF">━</span>) indicates the measured plant state and control inputs applied to the plant in the past, the blue lines (<span style="color:#0000FF">━</span>) indicate the predicted plant states and control inputs and the dashed red lines (<span style="color:#FF0000">╍</span>) indicate the constraints.</p> Full article ">Figure 7
<p>Confidence regions of the uncertain parameters considered in the adaptive NMPC variants at <math display="inline"><semantics> <mrow> <mi>t</mi> <mo>=</mo> <mn>0.05</mn> <mspace width="3.33333pt"/> <mi mathvariant="normal">h</mi> </mrow> </semantics></math>. <span style="color:#DDA0DD">■</span> represents the initial confidence region, <span style="color:#B0C4DE">■</span> represents the confidence region obtained using the observed measurements, <span style="color:#DCDCDC">■</span> represents the confidence region that is considered by the adaptive NMPC schemes and <span style="color:#00FF00">■</span> represents the parameter combinations that are used to build the scenario tree of the adaptive NMPC schemes.</p> Full article ">Figure 8
<p>Parameter combinations considered to be the true realization of the uncertain parameters chosen within the initial confidence region of the uncertain parameters to evaluate the performance NMPC controllers for different values of the tuning parameters.</p> Full article ">Figure 9
<p>Violin plots of the amount of product C produced in the first <math display="inline"><semantics> <mrow> <mn>0.3</mn> </mrow> </semantics></math> h in moles using non-adaptive and adaptive NMPC schemes with different lengths of prediction horizon <math display="inline"><semantics> <mrow> <mo>(</mo> <msub> <mi>N</mi> <mi>p</mi> </msub> <mo>)</mo> </mrow> </semantics></math> in the absence of measurement noise. <span style="color:#0000FF">■</span> represents MS NMPC, A-MS NMPC, <span style="color:#FF00FF">■</span> represents MS-VA NMPC, A-MS-VA NMPC, ■ represents MS-SB NMPC, A-MS-SB NMPC, and <span style="color:#DAA520">■</span> represents MS-CB NMPC, A-MS-CB NMPC. <span style="color:#00FF00">◆</span> and <span style="color:#FF0000">━</span> represent the mean and median values of the number of moles of product C produced.</p> Full article ">Figure 10
<p>Semi-log plots of the average computation time taken per iteration [in <math display="inline"><semantics> <mrow> <mo>[</mo> <mi mathvariant="normal">s</mi> <mo>]</mo> </mrow> </semantics></math>] by the different NMPC schemes for different values of the prediction horizon and robust horizon.</p> Full article ">Figure 11
<p>Violin plot of the amount of product C produced in the first <math display="inline"><semantics> <mrow> <mn>0.3</mn> </mrow> </semantics></math> h using MS-SB, A-MS-SB, MS-CB, and A-MS-CB NMPC schemes with different values of the scaling factor considered at the first stage <math display="inline"><semantics> <mrow> <mo>(</mo> <msub> <mi>κ</mi> <mn>0</mn> </msub> <mo>)</mo> </mrow> </semantics></math> in the absence of measurement noise. ■ represents MS-SB NMPC, A-MS-SB NMPC, and <span style="color:#DAA520">■</span> represents MS-CB NMPC, A-MS-CB NMPC. <span style="color:#00FF00">◆</span> and <span style="color:#FF0000">━</span> represent the mean and the median value.</p> Full article ">Figure 12
<p>Violin plot of the amount of product C produced during the first <math display="inline"><semantics> <mrow> <mn>0.3</mn> </mrow> </semantics></math> h using MS-SB, A-MS-SB, MS-CB, and A-MS-CB NMPC schemes with different values of the scaling increase factor <math display="inline"><semantics> <mrow> <mo>(</mo> <mi>β</mi> <mo>)</mo> </mrow> </semantics></math> in the absence of measurement noise. ■ represents MS-SB NMPC, A-MS-SB NMPC, and <span style="color:#DAA520">■</span> represents MS-CB NMPC, A-MS-CB NMPC. <span style="color:#00FF00">◆</span> and <span style="color:#FF0000">━</span> represent the mean and median values.</p> Full article ">Figure 13
<p>Process flow diagram of the industrial polymerization semi-batch reactor.</p> Full article ">Figure 14
<p>Input feed, temperatures of the coolant entering the jacket and entering the external heat exchanger, temperature of the reaction mixture, maximum attainable reactor temperature in the event of a cooling failure, and mass of the contents inside the reactor with their constraints when the reactor is controlled using the different NMPC controllers in the presence of measurement noise. The dotted vertical lines indicate the end times of the batches. Left figure: The plant is controlled using the non-adaptive approaches explained in <a href="#sec3-processes-08-00851" class="html-sec">Section 3</a>, Right figure: The plant is controlled using the adaptive approaches explained in <a href="#sec4-processes-08-00851" class="html-sec">Section 4</a>. NMPC (no mismatch)—the plant model and the simulation model are identical.</p> Full article ">Figure 15
<p>Reactor temperature predicted in the scenario tree of the MS-VA NMPC optimization problems solved at <math display="inline"><semantics> <mrow> <mi>t</mi> <mo>=</mo> <mn>0</mn> <mspace width="3.33333pt"/> <mi mathvariant="normal">h</mi> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>t</mi> <mo>=</mo> <mn>1.2</mn> <mspace width="3.33333pt"/> <mi mathvariant="normal">h</mi> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi>t</mi> <mo>=</mo> <mn>2.8</mn> <mspace width="3.33333pt"/> <mi mathvariant="normal">h</mi> </mrow> </semantics></math>. The magenta line (<span style="color:#FF00FF">━</span>) indicates the measured reactor temperature and control inputs applied to the plant until time <span class="html-italic">t</span>, the blue lines (<span style="color:#0000FF">━</span>) indicate the predicted plant states and control inputs and the dashed red lines (<span style="color:#FF0000">╍</span>) indicate the constraints.</p> Full article ">Figure 16
<p>(<b>a</b>): True plant parameter values chosen within the initial confidence region of the uncertain parameters to evaluate the performance of non-adaptive and adaptive NMPC schemes (<b>b</b>): The violin plot of the batch end time obtained when the plant is controlled using non-adaptive and adaptive NMPC schemes in the presence of measurement noise. <span style="color:#0000FF">■</span> represents MS NMPC, A-MS NMPC, <span style="color:#FF00FF">■</span> represents MS-VA NMPC, A-MS-VA NMPC, ■ represents MS-SB NMPC, A-MS-SB NMPC, and <span style="color:#DAA520">■</span> represents MS-CB NMPC, A-MS-CB NMPC. <span style="color:#00FF00">◆</span> and <span style="color:#FF0000">━</span> represent the mean and median values of the number of moles of product C produced.</p> Full article ">
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