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Processes
Volume 8
Issue 12
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Processes, Volume 8, Issue 12 (December 2020) – 166 articles

Cover Story (view full-size image): Under safety and reaction engineering aspects, good radial heat transfer is of outstanding importance in slender packed-beds. However, because of local wall effects, the radial heat transport in the near-wall region is limited. In this original research article, we study with particle-resolved CFD simulations and experiments the impact of internal heat fins on the near-wall radial heat transport in slender packed beds filled with spherical particles. The simulation results show that internal heat fins increase the conductive portion of the radial heat transport close to the reactor wall, leading to an overall increased thermal performance of the system. View this paper
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20 pages, 10491 KiB  
Article
Prototype of the Runway Monitoring Process at Smaller Airports: Edvard Rusjan Airport Maribor
by Boštjan Kovačič, Damjan Želodec and Damjan Doler
Processes 2020, 8(12), 1689; https://doi.org/10.3390/pr8121689 - 21 Dec 2020
Cited by 6 | Viewed by 2945
Abstract
The last 20-year announcement predicts a 3.5% increase in the number of yearly passengers which will result in the doubling of the number of passengers in air transport by 2037. Such anticipation indicates the need for efficient monitoring of airport infrastructure as the [...] Read more.
The last 20-year announcement predicts a 3.5% increase in the number of yearly passengers which will result in the doubling of the number of passengers in air transport by 2037. Such anticipation indicates the need for efficient monitoring of airport infrastructure as the support of opportune and efficient maintenance works. The novelties of this article are a process model of maintenance and monitoring, suitable for smaller and less burdened airports, and the methodology of monitoring of runways by implementation of the geodetic and geomechanics falling weight deflectometer (FWD) method. In addition, the results confirm the assumption that a specific environment such as an airport allows for sufficiently reliable determination of deformation areas or areas of vertical deviations of runways in a relative short time period available for measurements by using geodetic methods only or by combining other methods; our research model includes the FWD method. With the research, we have also shown there is an interaction between deformations or areas of vertical deviations on the surface and anomalies in the runway lower constructure which will, hereinafter, allow the development of the prediction, creating a vertical deviations or deformation model. Full article
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<p>Location of Edvard Rusjan Airport in Maribor. Source: Administration of the Republic of Slovenia for Civil Protection and Disaster Relief and Surveying and Mapping Authority.</p> Full article ">Figure 2
<p>The APMS-MB, Edvard Rusjan Airport in Maribor (MB) process model.</p> Full article ">Figure 3
<p>The monitoring process model, sub-process IMV-P_all, part 1.</p> Full article ">Figure 4
<p>The monitoring process model, sub-process IMV-P_all, part 2.</p> Full article ">Figure 5
<p>The monitoring process model, sub-process IMV-P_all, part 3.</p> Full article ">Figure 6
<p>The runway: (<b>a</b>) the measurement area; (<b>b</b>) the touchdown zone.</p> Full article ">Figure 7
<p>The used geodetic measurement equipment.</p> Full article ">Figure 8
<p>The used falling weight deflectometer (FWD) measurement equipment.</p> Full article ">Figure 9
<p>The trailer with the FWD measuring equipment.</p> Full article ">Figure 10
<p>The basic geodetic grid (yellow crosses) and measured perpendicular grid (green crosses).</p> Full article ">Figure 11
<p>Areas of maximum vertical deviations in the (<b>a</b>) first, (<b>b</b>) second, and (<b>c</b>) third periods of measurement.</p> Full article ">Figure 11 Cont.
<p>Areas of maximum vertical deviations in the (<b>a</b>) first, (<b>b</b>) second, and (<b>c</b>) third periods of measurement.</p> Full article ">Figure 12
<p>Comparison area.</p> Full article ">Figure 13
<p>Presentation of the measurement with the FWD device [<a href="#B46-processes-08-01689" class="html-bibr">46</a>].</p> Full article ">Figure 14
<p>The measurement area: measurements axes—a right axis (green), a middle axis (blue), and a left axis (yellow).</p> Full article ">Figure 15
<p>Vertical deviation of plane R1 from the grid.</p> Full article ">Figure 16
<p>Temperature-corrected deflections D0(T) under the loading plate measured in the middle axis.</p> Full article ">Figure 17
<p>Comparison of the results gained by geodetic and FWD measurements.</p> Full article ">Figure 18
<p>Schematic display of locational connection of the vertical deviation areas on the surface which are detected with geodetic measurements and anomalies in the lower structure detected with the FWD measurements.</p> Full article ">
16 pages, 36093 KiB  
Article
Mixing of Particles in a Rotating Drum with Inclined Axis of Rotation
by Parag Widhate, Haiping Zhu, Qinghua Zeng and Kejun Dong
Processes 2020, 8(12), 1688; https://doi.org/10.3390/pr8121688 - 21 Dec 2020
Cited by 8 | Viewed by 6209
Abstract
Various experimental and numerical studies have been carried out to study the mixing processes inside rotating drums with a horizontal axis of rotation in the past, but little effort has been made to investigate the rotating drums with an inclined axis of rotation, [...] Read more.
Various experimental and numerical studies have been carried out to study the mixing processes inside rotating drums with a horizontal axis of rotation in the past, but little effort has been made to investigate the rotating drums with an inclined axis of rotation, though such inclined drums exist in industrial waste management, food processing, power and pharmaceutical industries. To fill this gap, in this work, the discrete element method was used to study the mixing phenomena of a rotating drum for different angles of inclination from 0° to 15°. It was found that for inclined rotating drums, the whole bed Lacey mixing index is higher than that for the horizontal drum by 7.2% when the angle of inclination is 10°. The mixing index is related to the area ratio of the active region to the whole bed and volumetric fill. Increase in volumetric fill would lead to the decrease of the mixing index. The mixing index and area ratio exhibit similar patterns along the length of the drum for different angles of inclination. Full article
(This article belongs to the Special Issue DEM Simulations and Modelling of Granular Materials)
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<p>Inclined rotating drum from the axial view (red: small particles; and blue: large particles) (<span class="html-italic">L<sub>a</sub></span> is the distance to the bottom of the drum).</p> Full article ">Figure 2
<p>Mixing patterns of particles in the cross section located at <span class="html-italic">L<sub>a</sub></span> = 425 mm for different angles of inclination.</p> Full article ">Figure 3
<p>Schematic diagram of active and passive regions in a rotating drum.</p> Full article ">Figure 4
<p>Variation of net mass flow rate with time at three locations for different angles of inclination. The inset shows the net mass flow rate when <span class="html-italic">t</span> &lt; 8 s.</p> Full article ">Figure 5
<p>Fluctuation of net mass flow rate at three locations for different angles of inclination: (<b>a</b>) 0°; (<b>b</b>) 5°; (<b>c</b>) 10°; and (<b>d</b>) 15°.</p> Full article ">Figure 5 Cont.
<p>Fluctuation of net mass flow rate at three locations for different angles of inclination: (<b>a</b>) 0°; (<b>b</b>) 5°; (<b>c</b>) 10°; and (<b>d</b>) 15°.</p> Full article ">Figure 6
<p>Variation of volumetric fill along the length of the drum for the inclinations of 0°, 5°, 10°, and 15°.</p> Full article ">Figure 7
<p>Velocity field for α = 10° at <span class="html-italic">L<sub>a</sub></span> = 425 mm.</p> Full article ">Figure 8
<p>Bed surface velocity profile at <span class="html-italic">L<sub>a</sub></span> = 425 mm for 10° inclination at <span class="html-italic">t</span> = 30 s.</p> Full article ">Figure 9
<p>(<b>a</b>) Variation of the area ratio along the length of the drum for different angles of inclination at <span class="html-italic">t</span> = 30 s; and (<b>b</b>) average area ratio for different angles of inclination.</p> Full article ">Figure 10
<p>(<b>a</b>) Variation of the Lacey mixing index with time for different angles of inclination; and (<b>b</b>) average Lacey mixing index for different angles of inclination.</p> Full article ">Figure 11
<p>Variation of the Lacey mixing index along the length of the drum for different angles of inclination.</p> Full article ">Figure 12
<p>Dependence of Lacey mixing index and area ratio on volumetric fill.</p> Full article ">
12 pages, 6655 KiB  
Article
Comparative Study on CFD Turbulence Models for the Flow Field in Air Cooled Radiator
by Chao Yu, Xiangyao Xue, Kui Shi, Mingzhen Shao and Yang Liu
Processes 2020, 8(12), 1687; https://doi.org/10.3390/pr8121687 - 21 Dec 2020
Cited by 9 | Viewed by 2633
Abstract
This paper compares the performances of three Computational Fluid Dynamics (CFD) turbulence models, Reynolds Average Navier-Stokes (RANS), Detached Eddy Simulation (DES), and Large Eddy Simulation (LES), for simulating the flow field of a wheel loader engine compartment. The distributions of pressure fields, velocity [...] Read more.
This paper compares the performances of three Computational Fluid Dynamics (CFD) turbulence models, Reynolds Average Navier-Stokes (RANS), Detached Eddy Simulation (DES), and Large Eddy Simulation (LES), for simulating the flow field of a wheel loader engine compartment. The distributions of pressure fields, velocity fields, and vortex structures in a hybrid-grided engine compartment model are analyzed. The result reveals that the LES and DES can capture the detachment and breakage of the trailing edge more abundantly and meticulously than RANS. Additionally, by comparing the relevant calculation time, the feasibility of the DES model is proved to simulate the three-dimensional unsteady flow of engine compartment efficiently and accurately. This paper aims to provide a guiding idea for simulating the transient flow field in the engine compartment, which could serve as a theoretical basis for optimizing and improving the layout of the components of the engine compartment. Full article
(This article belongs to the Special Issue Advancement in Computational Fluid Mechanics and Optimization Methods)
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<p>Virtual wind tunnel model. (<b>a</b>) The whole model; (<b>b</b>) the wheel loader.</p> Full article ">Figure 2
<p>Simplified engine compartment.</p> Full article ">Figure 3
<p>Engine compartment virtual wind tunnel model meshing (x = 0 section).</p> Full article ">Figure 4
<p>Flow rate collection points of experiment.</p> Full article ">Figure 5
<p>Simulation calculation and experimental data comparison (at 2000 rpm).</p> Full article ">Figure 6
<p>2D contours of pressure magnitude at YZ plane.</p> Full article ">Figure 7
<p>2D contours of velocity magnitude at YZ plane.</p> Full article ">Figure 8
<p>2D contours of velocity magnitude at XY plane.</p> Full article ">Figure 9
<p>Vortex structures of the fan.</p> Full article ">Figure 10
<p>Prediction performance of three models.</p> Full article ">
15 pages, 1391 KiB  
Article
Subspace Based Model Identification for an Industrial Bioreactor: Handling Infrequent Sampling Using Missing Data Algorithms
by Nikesh Patel, Brandon Corbett, Johan Trygg, Chris McCready and Prashant Mhaskar
Processes 2020, 8(12), 1686; https://doi.org/10.3390/pr8121686 - 21 Dec 2020
Cited by 6 | Viewed by 2369
Abstract
This manuscript addresses the problem of modeling an industrial (Sartorius) bioreactor using process data. In the context of the Sartorius Bioreactor, it is important to appropriately address the problem of dealing with a large number of variables, which are not always measured or [...] Read more.
This manuscript addresses the problem of modeling an industrial (Sartorius) bioreactor using process data. In the context of the Sartorius Bioreactor, it is important to appropriately address the problem of dealing with a large number of variables, which are not always measured or are measured at different sampling rates, without taking recourse to simpler interpolation- or imputation-based approaches. To this end, a dynamic model for the Sartorius Bioreactor is developed via appropriately adapting a recently presented subspace model identification technique, which in turn uses nonlinear iterative partial least squares (NIPALS) algorithms to gracefully handle the missing data. The other key contribution is evaluating the ability of the identification approach to provide insight into the process by computing interpretable variables such as metabolite rates. The results demonstrate the ability of the proposed approach to model data from the Sartorius Bioreactor. Full article
(This article belongs to the Special Issue Modeling, Control, and Optimization of Batch and Batch-Like Processes)
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<p>The glucose input profiles for a training batch using the incorrect assumption of taking measurements whenever they are sampled.</p> Full article ">Figure 2
<p>The glucose input profiles for a training batch using the correct approach of updating the glucose concentration instantaneously.</p> Full article ">Figure 3
<p>The input profiles for a training batch.</p> Full article ">Figure 4
<p>The training fit (grey) from the dynamic model for each output are compared against the process data (black) for a training batch.</p> Full article ">Figure 5
<p>The process data (black) is compared with the dynamic model predictions using the state observer (grey solid) until the states converge and then the dynamic model predicts the remainder of the validation batch (grey starred).</p> Full article ">Figure 6
<p>The output predictions (grey) from the metabolite model for each output are compared against the process data (black) for one training batch.</p> Full article ">Figure 7
<p>The process data (black) is compared with the metabolite rate model predictions using the state observer (grey solid) until the states converge and then the metabolite rate model predicts the remainder of the validation batch (grey starred).</p> Full article ">Figure 8
<p>The process data (black) is compared with the model predictions batch (grey starred).</p> Full article ">
16 pages, 915 KiB  
Article
Characterization of a Wireless Vacuum Sensor Prototype Based on the SAW-Pirani Principle
by Sofia Toto, Mazin Jouda, Jan G. Korvink, Suparna Sundarayyan, Achim Voigt, Hossein Davoodi and Juergen J. Brandner
Processes 2020, 8(12), 1685; https://doi.org/10.3390/pr8121685 - 21 Dec 2020
Cited by 2 | Viewed by 2955
Abstract
A prototype of a wireless vacuum microsensor combining the Pirani principle and surface acoustic waves (SAW) with extended range and sensitivity was designed, modelled, manufactured and characterised under different conditions. The main components of the prototype are a sensing SAW chip, a heating [...] Read more.
A prototype of a wireless vacuum microsensor combining the Pirani principle and surface acoustic waves (SAW) with extended range and sensitivity was designed, modelled, manufactured and characterised under different conditions. The main components of the prototype are a sensing SAW chip, a heating coil and an interrogation antenna. All the components were assembled on a 15 mm × 11 mm × 3 mm printed circuit board (PCB). The behaviour of the PCB was characterised under ambient conditions and in vacuum. The quality of the SAW interrogation signal, the frequency shift and the received current of the coil were measured for different configurations. Pressures between 0.9 and 100,000 Pa were detected with sensitivities between 2.8 GHz/Pa at 0.9 Pa and 1 Hz/Pa close to atmospheric pressure. This experiment allowed us to determine the optimal operating conditions of the sensor and the integration conditions inside a vacuum chamber in addition to obtaining a pressure-dependent signal. Full article
(This article belongs to the Special Issue Advances in Microfluidics Technology for Diagnostics and Detection)
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<p>Schematic of the vacuum test rig showing its components.</p> Full article ">Figure 2
<p>Top view of the test rig showing the window. The Tx coil and the Tx antenna are placed on top of the window. (<b>a</b>) SMA cable going to the network analyser. (<b>b</b>) Sensor PCB. (<b>c</b>) Transmitting coil. (<b>d</b>) Cable inside vacuum connecting the receiver coil and the heating resistor. (<b>e</b>) PMMA window.</p> Full article ">Figure 3
<p>Complete test rig: (<b>a</b>) Voltage source. (<b>b</b>) Arbitrary waveform generator. (<b>c</b>) Vacuum pump. (<b>d</b>) Valve to protect the turbo pump. (<b>e</b>) Pressure sensor. (<b>f</b>) Vector network analyser. (<b>g</b>) Window setup shown in <a href="#processes-08-01685-f002" class="html-fig">Figure 2</a>.</p> Full article ">Figure 4
<p>Comparison of the antenna signal with a pump running and with no pump running: (<b>a</b>) The antenna’s self resonance, main peak. (<b>b</b>) The antenna’s self resonance, second peak. (<b>c</b>) Surface acoustic waves (SAW) chip resonance peak. RL is the gain and RP is the phase. Peaks are less sharp with the pump running.</p> Full article ">Figure 5
<p>SAW peak frequency vs. pressure.</p> Full article ">Figure 6
<p>Sensitivity of the SAW chip resonance frequency vs. pressure in Hz/Pa. A logarithmic scale for the pressure axis was used for the sake of clarity.</p> Full article ">Figure 7
<p><math display="inline"><semantics> <msub> <mi>S</mi> <mn>11</mn> </msub> </semantics></math> gain at the SAW chip resonance frequency vs. pressure in dB.</p> Full article ">Figure 8
<p><math display="inline"><semantics> <msub> <mi>S</mi> <mn>11</mn> </msub> </semantics></math> phase at the SAW chip resonance frequency vs. pressure in kPa.</p> Full article ">Figure 9
<p>Temperature of the chip versus pressure.</p> Full article ">
20 pages, 6312 KiB  
Article
Flow and Diffusion Characteristics of Typical Halon Extinguishing Agent Substitute under Different Release Pressures
by Jiaming Jin, Renming Pan, Ruiyu Chen, Xiaokang Xu and Quanwei Li
Processes 2020, 8(12), 1684; https://doi.org/10.3390/pr8121684 - 21 Dec 2020
Cited by 4 | Viewed by 2394
Abstract
To provide guidance towards reducing the weight of the HFC-125 storage vessel by reducing the release pressure and to reveal the effects of release pressure on the extinguishing efficiency of HFC-125, we investigated the flow and diffusion characteristics of HFC-125 under six release [...] Read more.
To provide guidance towards reducing the weight of the HFC-125 storage vessel by reducing the release pressure and to reveal the effects of release pressure on the extinguishing efficiency of HFC-125, we investigated the flow and diffusion characteristics of HFC-125 under six release pressures in the present study. The influence of release pressure on the degree of superheat, injection duration, pressure loss, jet angle, and concentration distribution were analyzed. Results show that the degree of superheat and the injection duration both decreased with the release pressure. The bubble expansion in the HFC-125 could slow down the pressure decrease in the storage vessel. The flow process in the pipeline can be divided into three phases: pipeline filling, stable flow, and mixed gases release. Both of the maximum and mean values of the pipeline pressure loss increased with the release pressure. The maximum concentration value decreased with the increase of the distance from the nozzle. The maximum concentration value in the near field from the nozzle increased with the release pressure. The concentration and holding time (duration above 17.6% volume concentration) of HFC-125 in the near field from the nozzle met the requirements of minimum performance standards (MPS) for HFC-125. Full article
(This article belongs to the Special Issue Green Technologies for Production Processes)
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<p>The full-scale airborne fire extinguishing system.</p> Full article ">Figure 2
<p>The location of sampling points.</p> Full article ">Figure 3
<p>The saturated vapor pressure versus saturation temperature of HFC-125.</p> Full article ">Figure 4
<p><span class="html-italic">D</span><sub>sup</sub> of the HFC-125 agent as a function of release pressure.</p> Full article ">Figure 5
<p>The injection duration of HFC-125 under different release pressures.</p> Full article ">Figure 6
<p>The vessel pressure of HFC-125 agent under various release pressures.</p> Full article ">Figure 7
<p>The differential pressure of HFC-125 under different release pressures.</p> Full article ">Figure 8
<p>Phase division determined by the differential pressure curve in the pipeline at 4.14 MPa.</p> Full article ">Figure 9
<p>(<b>a</b>) The maximum and mean values of differential pressure in the whole process. (<b>b</b>) The mean value of differential pressure in each phase.</p> Full article ">Figure 10
<p>Jet angle.</p> Full article ">Figure 11
<p>The injection process of HFC-125 agent obtained by the high-speed camera.</p> Full article ">Figure 12
<p>The maximum jet angle versus the release pressure.</p> Full article ">Figure 13
<p>Concentration as a function of time at points 4, 5, 6, 7, and 8 in Section II in the case of 3.45 MPa.</p> Full article ">Figure 14
<p>Concentration versus time at points 9, 10, 11, and 12 in Section III in the case of 3.45 MPa.</p> Full article ">Figure 15
<p>The backflow recorded by the high-speed camera.</p> Full article ">Figure 16
<p>(<b>a</b>) Concentration of HFC-125 as a function of time at point 1; (<b>b</b>) the maximum value of concentration value with different release pressure at point 1; (<b>c</b>) concentration of HFC-125 as a function of time at point 8; (<b>d</b>) concentration of HFC-125 as a function of time at point 9.</p> Full article ">Figure 17
<p>The holding time at points 1 and 8 at different release pressures.</p> Full article ">
32 pages, 3390 KiB  
Review
Iron-Based Catalytically Active Complexes in Preparation of Functional Materials
by Katarzyna Rydel-Ciszek, Tomasz Pacześniak, Izabela Zaborniak, Paweł Błoniarz, Karolina Surmacz, Andrzej Sobkowiak and Paweł Chmielarz
Processes 2020, 8(12), 1683; https://doi.org/10.3390/pr8121683 - 20 Dec 2020
Cited by 12 | Viewed by 5312
Abstract
Iron complexes are particularly interesting as catalyst systems over the other transition metals (including noble metals) due to iron’s high natural abundance and mediation in important biological processes, therefore making them non-toxic, cost-effective, and biocompatible. Both homogeneous and heterogeneous catalysis mediated by iron [...] Read more.
Iron complexes are particularly interesting as catalyst systems over the other transition metals (including noble metals) due to iron’s high natural abundance and mediation in important biological processes, therefore making them non-toxic, cost-effective, and biocompatible. Both homogeneous and heterogeneous catalysis mediated by iron as a transition metal have found applications in many industries, including oxidation, C-C bond formation, hydrocarboxylation and dehydration, hydrogenation and reduction reactions of low molecular weight molecules. These processes provided substrates for industrial-scale use, e.g., switchable materials, sustainable and scalable energy storage technologies, drugs for the treatment of cancer, and high molecular weight polymer materials with a predetermined structure through controlled radical polymerization techniques. This review provides a detailed statement of the utilization of homogeneous and heterogeneous iron-based catalysts for the synthesis of both low and high molecular weight molecules with versatile use, focusing on receiving functional materials with high potential for industrial application. Full article
(This article belongs to the Special Issue Engineering Reversible Deactivation Radical Polymerization in the Second Century of Macromolecular Science)
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<p>(<b>a</b>) Various types of tetradentate ligand; (<b>b</b>) coordination geometry at the metal center of iron(II) benzilate complexes; (<b>c</b>) The mechanism of oxidative decarboxylation of iron(II) benzilate complexes of tridentate ligands as follows: formation of iron(III) superoxide radical intermediate (II) and analogous iron(III) superoxide radical intermediate (II′), followed by generation of iron(III) hydroperoxo oxyl radical intermediates (III and III′) due to hydrogen atom abstraction from the hydroxy group of α-hydroxy acid. Decarboxylation of III and III′ generates iron(II) hydroperoxo intermediates (IV and V) that could oxidize sulfide to sulfoxide and sulfone, and provide <span class="html-italic">cis</span>-diol product in reactions with olefins (only V) [<a href="#B31-processes-08-01683" class="html-bibr">31</a>]. TPA is equivalent to the TPMA abbreviation. Reprinted with permission from American Chemical Society, Copyright 2016.</p> Full article ">Figure 2
<p>(<b>a</b>) Tetradentate ligands in bio-inspired non-heme iron-mediated olefin oxidations; (<b>b</b>) Activation of H<sub>2</sub>O<sub>2</sub> by non-heme iron oxidation catalysts with the assistance of water or carboxylic acids with TPMA- (1–3) and TPMA*-based (1 *–3 *) complexes [<a href="#B6-processes-08-01683" class="html-bibr">6</a>]. Reprinted with permission from Nature Publishing Group, a division of Macmillan Publishers Limited, Copyright 2014. (<b>c</b>) Gram-scale <span class="html-italic">syn-</span>dihydroxylation of cholesteryl oleate catalyzed by <sup>tips3</sup>TPMA (1) with H<sub>2</sub>O<sub>2</sub> as oxidant [<a href="#B4-processes-08-01683" class="html-bibr">4</a>]. Reprinted with permission from American Chemical Society, Copyright 2018.</p> Full article ">Figure 3
<p>(<b>a</b>) Catalytic epoxidation of olefins using <span class="html-italic">N</span>-heterocyclic carbene complex (NCCN) and H<sub>2</sub>O<sub>2</sub> as the oxidant [<a href="#B8-processes-08-01683" class="html-bibr">8</a>]. Reprinted with permission from WILEY-VCH Verlag GmbH &amp; Co. KGaA, Copyright 2014. (<b>b</b>) <span class="html-italic">N</span>-heterocyclic carbene complex-(carbenodiamidine)Fe(4-methoxyphenoxide)<sub>2</sub> (2) in polymerization of lactide [<a href="#B55-processes-08-01683" class="html-bibr">55</a>]. Reprinted with permission from Elsevier Ltd., Copyright 2014.</p> Full article ">Figure 4
<p>Heterogeneous catalysts: (<b>a</b>) Synthetic routes for the preparation of iron (Fe) single clusters immobilized on <span class="html-italic">N</span>-doped porous carbon (C/TP-Fe700 SMCs) and iron-based nanoparticles (C/Fe700 NPs) [<a href="#B83-processes-08-01683" class="html-bibr">83</a>]. Reprinted with permission from WILEY-VCH Verlag GmbH &amp; Co. KGaA, Copyright 2018. (<b>b</b>) Preparation of Fe<sub>2</sub>O<sub>3</sub>-based nanocatalysts by pyrolysis on carbon support [<a href="#B91-processes-08-01683" class="html-bibr">91</a>]. Reprinted with permission from WILEY-VCH Verlag GmbH &amp; Co. KGaA, Copyright 2015. (<b>c</b>) Multiscale porous Fe-N-C catalyst produced with SiO2 and Zn as co-templates [<a href="#B94-processes-08-01683" class="html-bibr">94</a>]. Reprinted with permission from Royal Society of Chemistry, Copyright 2019.</p> Full article ">Figure 5
<p>Synthetic route for the preparation of fluorescent/magnetic nanoparticles via iron-catalyzed ATRP [<a href="#B133-processes-08-01683" class="html-bibr">133</a>]. Reprinted with permission from American Chemical Society, Copyright 2011.</p> Full article ">Figure 6
<p>(<b>a</b>) Synthetic route for the preparation of MNPs characterized by bifunctional properties i.e., NIR fluorescence and magnetism by iron-mediated SI-AGET ATRP, subsequently modified by pH-activatable benzo[<span class="html-italic">a</span>]phenoxazine derivatives; (<b>b</b>) In vivo NIR fluorescence images of prepared hybrid material in 4T1 tumor-bearing mouse at indicated times after intravenous administration [<a href="#B135-processes-08-01683" class="html-bibr">135</a>]. Reprinted with permission from Royal Society of Chemistry, Copyright 2015.</p> Full article ">Figure 7
<p>Modification of chitosan nanospheres (CTSNSs) by SI-AGET ATRP mediated by iron catalyst [<a href="#B141-processes-08-01683" class="html-bibr">141</a>]. Reprinted with permission from American Chemical Society, Copyright 2009.</p> Full article ">
18 pages, 2493 KiB  
Article
An Integrated Approach to the Design of Centralized and Decentralized Biorefineries with Environmental, Safety, and Economic Objectives
by Antioco López-Molina, Debalina Sengupta, Claire Shi, Eman Aldamigh, Maha Alandejani and Mahmoud M. El-Halwagi
Processes 2020, 8(12), 1682; https://doi.org/10.3390/pr8121682 - 20 Dec 2020
Cited by 13 | Viewed by 3671
Abstract
Biorefineries provide economic, environmental, and social benefits towards sustainable development. Because of the relatively small size of typical biorefineries compared to oil and gas processes, it is necessary to evaluate the options of decentralized (or distributed) plants that are constructed near the biomass [...] Read more.
Biorefineries provide economic, environmental, and social benefits towards sustainable development. Because of the relatively small size of typical biorefineries compared to oil and gas processes, it is necessary to evaluate the options of decentralized (or distributed) plants that are constructed near the biomass resources and product markets versus centralized (or consolidated) facilities that collect biomass from different regions and distribute the products to the markets, benefiting from the economy of scale but suffering from the additional transportation costs. The problem is further compounded when, in addition to the economic factors, environmental and safety aspects are considered. This work presents an integrated approach to the design of biorefining facilities while considering the centralized and decentralized options and the economic, environmental, and safety objectives. A superstructure representation is constructed to embed the various options of interest. A mathematical programming formulation is developed to transform the problem into an optimization problem. A new correlation is developed to estimate the capital cost of biorefineries and to facilitate the inclusion of the economic functions in the optimization program without committing to the type of technology or the size of the plant. A new metric called Total Process Risk is also introduced to evaluate the relative risk of the process. Life cycle analysis is applied to evaluate environmental emissions. The environmental and safety objectives are used to establish tradeoffs with the economic objectives. A case study is solved to illustrate the value and applicability of the proposed approach. Full article
(This article belongs to the Special Issue Process Systems Engineering Tools for the Design of Ionic Liquids and Integrated Biorefineries)
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<p>Flowchart summarizing the methodology.</p> Full article ">Figure 2
<p>Superstructure of centralized and decentralized biorefining options.</p> Full article ">Figure 3
<p>Biomass availability and relative locations for the case study.</p> Full article ">Figure 4
<p>Key process inputs and outputs for a basis of one tonne methanol.</p> Full article ">Figure 5
<p>Economically optimum solution with a centralized facility (ROI is return on investment).</p> Full article ">Figure 6
<p>Suboptimal solution with centralized and decentralized facilities.</p> Full article ">
16 pages, 2529 KiB  
Article
The Effects of Biofertilizers on Growth, Soil Fertility, and Nutrients Uptake of Oil Palm (Elaeis Guineensis) under Greenhouse Conditions
by Aaronn Avit Ajeng, Rosazlin Abdullah, Marlinda Abdul Malek, Kit Wayne Chew, Yeek-Chia Ho, Tau Chuan Ling, Beng Fye Lau and Pau Loke Show
Processes 2020, 8(12), 1681; https://doi.org/10.3390/pr8121681 - 19 Dec 2020
Cited by 44 | Viewed by 8640
Abstract
The full dependency on chemical fertilizers in oil palm plantation poses an enormous threat to the ecosystem through the degradation of soil and water quality through leaching to the groundwater and contaminating the river. A greenhouse study was conducted to test the effect [...] Read more.
The full dependency on chemical fertilizers in oil palm plantation poses an enormous threat to the ecosystem through the degradation of soil and water quality through leaching to the groundwater and contaminating the river. A greenhouse study was conducted to test the effect of combinations of biofertilizers with chemical fertilizer focusing on the soil fertility, nutrient uptake, and the growth performance of oil palms seedlings. Soils used were histosol, spodosol, oxisol, and ultisol. The three treatments were T1: 100% chemical fertilizer (NPK 12:12:17), T2: 70% chemical fertilizer + 30% biofertilizer A (CF + BFA), and T3: 70% + 30% biofertilizer B (CF + BFB). T2 and T3, respectively increased the growth of oil palm seedlings and soil nutrient status but seedlings in oxisol and ultisol under T3 had the highest in almost all parameters due to the abundance of more efficient PGPR. The height of seedlings in ultisol under T3 was 22% and 17% more than T2 and T1 respectively, with enhanced girth size, chlorophyll content, with improved nutrient uptake by the seedlings. Histosol across all treatments has a high macronutrient content suggesting that the rate of chemical fertilizer application should be revised when planting using the particular soil. With the reduction of chemical fertilizer by 25%, the combined treatment with biofertilizers could enhance the growth of the oil palm seedlings and soil nutrient properties regardless of the soil orders. Full article
(This article belongs to the Special Issue Biotechnology for Sustainability and Social Well Being)
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<p>Highest frond height of oil palm seedlings at the end of treatment (DAT 131). Vertical bar represents the standard deviation. Different letters represent significant differences in Tukey’s HSD comparison. Means sharing the same letter across treatments do not differ significantly at <span class="html-italic">p</span>-value ≤ 0.05.</p> Full article ">Figure 2
<p>Girth size of the seedlings throughout the treatment period. Vertical bar represents the standard deviation. Different letters represent significant differences in Tukey’s HSD comparison. Means sharing the same letter across treatments do not differ significantly at <span class="html-italic">p</span>-value ≤ 0.05.</p> Full article ">Figure 3
<p>Chlorophyll index of the seedlings throughout the treatment period. Vertical bar represents the standard deviation. Different letters represent significant differences in Tukey’s HSD comparison. Means sharing the same letter across treatments do not differ significantly at <span class="html-italic">p</span>-value (<span class="html-italic">p</span> ≤ 0.05).</p> Full article ">Figure 4
<p>Soil macronutrient content (NPK) after the harvest. Vertical bar represents the standard deviation. Different letters represent significant differences in Tukey’s HSD comparison. Means sharing the same letter across treatments do not differ significantly at <span class="html-italic">p</span>-value (<span class="html-italic">p</span> ≤ 0.05).</p> Full article ">Figure 5
<p>NPK uptake by the seedlings at time of harvest. Vertical bar represents the standard deviation. Different letters represent significant differences in Tukey’s HSD comparison. Means sharing the same letter across treatments do not differ significantly at <span class="html-italic">p</span>-value (<span class="html-italic">p</span> ≤ 0.05).</p> Full article ">Figure 6
<p>Roots of oil palm seedlings at the end of treatment. (<b>a</b>)T1, (<b>b</b>) T2, and (<b>c</b>) T3. The roots of oil palm seedlings treated with T3 were more in number, longer with more root hairs followed by seedlings in T2 then 100% T1 plots.</p> Full article ">
21 pages, 8022 KiB  
Review
Ultrasonically Induced Polymerization and Polymer Grafting in the Presence of Carbonaceous Nanoparticles
by Sarah Cohen, Evgeni Zelikman and Ran Yosef Suckeveriene
Processes 2020, 8(12), 1680; https://doi.org/10.3390/pr8121680 - 19 Dec 2020
Cited by 11 | Viewed by 3636
Abstract
Nanotechnology refers to technologies using at least one nanometric dimension. Most advances have been in the field of nanomaterials used in research and industry. The vast potential of polymeric nanocomposites for advanced materials and applications such as hybrid nanocomposites with customized electrical conductivity, [...] Read more.
Nanotechnology refers to technologies using at least one nanometric dimension. Most advances have been in the field of nanomaterials used in research and industry. The vast potential of polymeric nanocomposites for advanced materials and applications such as hybrid nanocomposites with customized electrical conductivity, anti-bacterial, anti-viral, and anti-fog properties have attracted considerable attention. The number of studies on the preparation of nanocomposites in the presence of carbon materials, i.e., carbon nanotubes (CNTs) and graphene, has intensified over the last decade with the growing interest in their outstanding synergic properties. However, the functionality of such nanocomposites depends on overcoming three key challenges: (a) the breakdown of nanoparticle agglomerates; (b) the attachment of functional materials to the nanoparticle surfaces; and (c) the fine dispersion of functional nanoparticles within the polymeric matrices. Ultrasonic polymerization and grafting in the presence of nanoparticles is an innovative solution that can meet these three challenges simultaneously. These chemical reactions are less well known and only a few research groups have dealt with them to date. This review focuses on two main pathways to the design of ultrasonically induced carbon-based nanocomposites: the covalent approach which is based on the chemical interactions between the carbon fillers and the matrix, and the non-covalent approach which is based on the physical interactions. Full article
(This article belongs to the Special Issue Polymerization Technologies in the Presence of Nanoparticles)
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Figure 1
<p>Core-shell structure of multi-walle carbon nanotube-g-poly(3-hexylthiophene) (MWCNT-g-P3HT) nanocomposites prepared by the “grafting-from” method (Reprinted (adapted) with permission from Hou, W.; Zhao, N.-J.; Meng, D.; Tang, J.; Zeng, Y.; Wu, Y.; Weng, Y.; Cheng, C.; Xu, X.; Li, Y.; et al. Controlled Growth of Well-Defined Conjugated Polymers from the Surfaces of Multiwalled Carbon Nanotubes: Photoresponse Enhancement via Charge Separation. <span class="html-italic">ACS Nano</span> <b>2016</b>, <span class="html-italic">10</span>, 5189–5198 [<a href="#B20-processes-08-01680" class="html-bibr">20</a>]. Copyright (2020) American Chemical Society.).</p> Full article ">Figure 2
<p>Energy-band diagrams of P3HT and MWNTs (Reprinted (adapted) with permission from Hou, W.; Zhao, N.-J.; Meng, D.; Tang, J.; Zeng, Y.; Wu, Y.; Weng, Y.; Cheng, C.; Xu, X.; Li, Y.; et al. Controlled Growth of Well-Defined Conjugated Polymers from the Surfaces of Multiwalled Carbon Nanotubes: Photoresponse Enhancement via Charge Separation. <span class="html-italic">ACS Nano</span> <b>2016</b>, <span class="html-italic">10</span>, 5189–5198 [<a href="#B20-processes-08-01680" class="html-bibr">20</a>]. Copyright (2020) American Chemical Society.).</p> Full article ">Figure 3
<p>Preparation of poly(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) (PTMA) covalently grafted from MWCNTs by grafting-from polymerization (Republished with permission (2020) of the Royal Society of Chemistry from Ernould, B.; Devos, M.; Bourgeois, J.-P.; Rolland, J.; Vlad, A.; Gohy, J.-F. Grafting of a Redox Polymer onto Carbon Nanotubes for High Capacity Battery Materials. <span class="html-italic">J. Mater. Chem. A.</span> <b>2015</b>, <span class="html-italic">3</span>, 8832–8839 [<a href="#B5-processes-08-01680" class="html-bibr">5</a>]. Permission conveyed through Copyright Clearance Center Inc.).</p> Full article ">Figure 4
<p>Transmission electron microscopy (TEM) micrographs of (<b>a</b>) pristine MWCNTs and (<b>b</b>) MWCNT-g-poly(2,2,6,6-tetramethyl-4-piperidyl methacrylate) (PTMPM) (MWCNT-g-PTMPM)—Scale bars: 100 nm (Republished with permission (2020) of the Royal Society of Chemistry from Ernould, B.; Devos, M.; Bourgeois, J.-P.; Rolland, J.; Vlad, A.; Gohy, J.-F. Grafting of a Redox Polymer onto Carbon Nanotubes for High Capacity Battery Materials. <span class="html-italic">J. Mater. Chem. A.</span> <b>2015</b>, <span class="html-italic">3</span>, 8832–8839 [<a href="#B5-processes-08-01680" class="html-bibr">5</a>]. Permission conveyed through Copyright Clearance Center Inc.).</p> Full article ">Figure 5
<p>Microscopic images of (<b>A</b>) poly(amidoamine)-free single-walled carbon nanotube-based epoxy matrix, PAMAM/SWCNTs/EP, with (<b>B</b>) 1 and (<b>C</b>) 2 as number generation and (<b>D</b>) field emission scanning electron microscope (FESEM) images of PAMAM/SWCNTs/EP with grafting generation 2 (Reprinted (adapted) with permission from Che, J.; Yuan, W.; Jiang, G.; Dai, J.; Lim, S.Y.; Chan-Park, M.B. Epoxy Composite Fibers Reinforced with Aligned Single-Walled Carbon Nanotubes Functionalized with Generation 0−2 Dendritic Poly(Amidoamine). <span class="html-italic">Chem. Mater.</span> <b>2009</b>, <span class="html-italic">21</span>, 1471–1479 [<a href="#B22-processes-08-01680" class="html-bibr">22</a>]. Copyright (2020) American Chemical Society.).</p> Full article ">Figure 6
<p>Atomic force microscopy (AFM) image of vertically aligned (VA)-SWCNTs/polystyrene (PS) nanocomposites (Reprinted from Macdonald, T.J.; Gibson, C.T.; Constantopoulos, K.; Shapter, J.G.; Ellis, A.V. Functionalization of Vertically Aligned Carbon Nanotubes with Polystyrene via Surface Initiated Reversible Addition Fragmentation Chain Transfer Polymerization. <span class="html-italic">Appl. Surf. Sci.</span> <b>2012</b>, <span class="html-italic">258</span>, 2836–2843 [<a href="#B16-processes-08-01680" class="html-bibr">16</a>], with permission (2020) from Elsevier).</p> Full article ">Figure 7
<p>FESEM images of VA-CNTs (<b>a</b>) before and (<b>b</b>) after the grafting of polyaniline by a grafting-from method (Reprinted from Haq, A.U.; Lim, J.; Yun, J.M.; Lee, W.J.; Han, T.H.; Kim, S.O. Direct Growth of Polyaniline Chains from N-Doped Sites of Carbon Nanotubes. <span class="html-italic">Small</span> <b>2013</b>, <span class="html-italic">9</span>, 3829–3833 [<a href="#B23-processes-08-01680" class="html-bibr">23</a>], with permission (2020) from WILEY).</p> Full article ">Figure 8
<p>High resolution scanning electron microscopy (HRSEM) image of MWCNT/PANI nanocomposites prepared by ultrasonically induced inverse emulsion polymerization (Reprinted from Zelikman, E.; Suckeveriene, R.Y.; Mechrez, G.; Narkis, M. Fabrication of Composite Polyaniline/CNT Nanofibers Using an Ultrasonically Assisted Dynamic Inverse Emulsion Polymerization Technique. <span class="html-italic">Polym. Adv. Technol.</span> <b>2009</b>, <span class="html-italic">21</span>, 150–152 [<a href="#B28-processes-08-01680" class="html-bibr">28</a>], with permission (2020) from WILEY).</p> Full article ">Figure 9
<p>Fabrication via in situ inverse emulsion polymerization of the styrene=isoprene-styrene (SIS)/CNT/PANI elastomeric nanocomposite film by precipitation-filtration or drop-casting and (<b>a</b>) schematic structure of the resulting composites and (<b>b</b>) HRSEM images (Reprinted from Brook, I.; Mechrez, G.; Suckeveriene, R.Y.; Tchoudakov, R.; Lupo, S.; Narkis, M. The Structure and Electro-Mechanical Properties of Novel Hybrid CNT/PANI Nanocomposites. <span class="html-italic">Polym. Compos.</span> <b>2014</b>, <span class="html-italic">35</span>, 788–794 [<a href="#B29-processes-08-01680" class="html-bibr">29</a>]; and from Brook, I.; Mechrez, G.; Suckeveriene, R.Y.; Tchoudakov, R.; Lupo, S.; Narkis, M. Electrically Conductive Hybrid Elastomeric Nanocomposites. <span class="html-italic">Composites</span> <b>2013</b>, <span class="html-italic">161</span>, 1–3 [<a href="#B30-processes-08-01680" class="html-bibr">30</a>], with permission (2020) from WILEY).</p> Full article ">Figure 10
<p>Preparation of PANI-based modified graphene (MGA) or PPy-based modified graphene (MGP) nanocomposites using (<b>A</b>) modified graphene and (<b>B</b>) pristine graphene yielding PANI/Graphene (GA) and PPy/Graphene (GP) (Reprinted from Sahoo, S.; Bhattacharya, P.; Hatui, G.; Ghosh, D.; Das, C.K. Sonochemical Synthesis and Characterization of Amine-Modified Graphene/Conducting Polymer Nanocomposites. <span class="html-italic">J. Appl. Polym. Sci.</span> <b>2012</b>, <span class="html-italic">128</span>, 1476–1483 [<a href="#B6-processes-08-01680" class="html-bibr">6</a>], with permission (2020) from WILEY).</p> Full article ">Figure 11
<p>FESEM images of pristine graphene-based nanocomposites wrapped with (<b>a</b>) PANI and (<b>b</b>) PPy and modified graphene-based with (<b>c</b>) PANI and (<b>d</b>) PPy, at a magnification of 260.00 KX except for (<b>a</b>) 200.00 KX (Reprinted from Sahoo, S.; Bhattacharya, P.; Hatui, G.; Ghosh, D.; Das, C.K. Sonochemical Synthesis and Characterization of Amine-Modified Graphene/Conducting Polymer Nanocomposites. <span class="html-italic">J. Appl. Polym. Sci.</span> <b>2012</b>, <span class="html-italic">128</span>, 1476–1483 [<a href="#B6-processes-08-01680" class="html-bibr">6</a>], with permission (2020) from WILEY).</p> Full article ">Figure 12
<p>Preparation flow for graphene/MWCNT/PS film using divinylbenzene (DVB) crosslinker (Reprinted from Patole, A.S.; Patole, S.P.; Jung, S.-Y.; Yoo, J.-B.; An, J.-H.; Kim, T.-H. Self Assembled Graphene/Carbon Nanotube/Polystyrene Hybrid Nanocomposite by in Situ Microemulsion Polymerization. <span class="html-italic">Eur. Polym. J.</span> <b>2012</b>, <span class="html-italic">48</span>, 252–259 [<a href="#B7-processes-08-01680" class="html-bibr">7</a>], with permission (2020) from Elsevier).</p> Full article ">Figure 13
<p>(<b>a</b>) SEM image of exfoliated graphene and the graphene/MWCNT/PS nanocomposites prepared by in situ micro-emulsion polymerization observed by (<b>b</b>) SEM and (<b>c</b>) TEM (Reprinted from Patole, A.S.; Patole, S.P.; Jung, S.-Y.; Yoo, J.-B.; An, J.-H.; Kim, T.-H. Self Assembled Graphene/Carbon Nanotube/Polystyrene Hybrid Nanocomposite by in Situ Microemulsion Polymerization. <span class="html-italic">Eur. Polym. J.</span> <b>2012</b>, <span class="html-italic">48</span>, 252–259 [<a href="#B7-processes-08-01680" class="html-bibr">7</a>], with permission (2020) from Elsevier).</p> Full article ">Figure 14
<p>Fabrication of modified graphene oxide through ultrasonication assisted by silanization (Reprinted from Zhang, L.; Wu, H.; Zheng, Z.; He, H.; Wei, M.; Huang, X. Fabrication of Graphene Oxide/Multi-Walled Carbon Nanotube/Urushiol Formaldehyde Polymer Composite Coatings and Evaluation of Their PhysiCo-Mechanical Properties and Corrosion Resistance. <span class="html-italic">Prog. Org. Coatings</span> <b>2019</b>, <span class="html-italic">127</span>, 131–139 [<a href="#B47-processes-08-01680" class="html-bibr">47</a>], with permission (2020) from Elsevier).</p> Full article ">Figure 15
<p>SEM images of (<b>a</b>) the MWCNTs/urushiol formaldehyde polymer (UFP) and (<b>b</b>) the GO/MWCNTs/UFP films (<b>c</b>) after its deposition on a silicon substrate (Reprinted from Zhang, L.; Wu, H.; Zheng, Z.; He, H.; Wei, M.; Huang, X. Fabrication of Graphene Oxide/Multi-Walled Carbon Nanotube/Urushiol Formaldehyde Polymer Composite Coatings and Evaluation of Their PhysiCo-Mechanical Properties and Corrosion Resistance. <span class="html-italic">Prog. Org. Coatings</span> <b>2019</b>, <span class="html-italic">127</span>, 131–139 [<a href="#B47-processes-08-01680" class="html-bibr">47</a>], with permission (2020) from Elsevier).</p> Full article ">
17 pages, 6168 KiB  
Article
Experimental Study on Ramp Shock Wave Control in Ma3 Supersonic Flow Using Two-Electrode SparkJet Actuator
by Wei Xie, Zhenbing Luo, Yan Zhou, Lin Wang, Wenqiang Peng and Tianxiang Gao
Processes 2020, 8(12), 1679; https://doi.org/10.3390/pr8121679 - 19 Dec 2020
Cited by 5 | Viewed by 2213
Abstract
The control of a shock wave produced by a ramp (ramp shock) in Ma3 supersonic flow using a two-electrode SparkJet (SPJ) actuator in a single-pulse mode is studied experimentally. Except for schlieren images of the interaction process of SPJ with the flow field, [...] Read more.
The control of a shock wave produced by a ramp (ramp shock) in Ma3 supersonic flow using a two-electrode SparkJet (SPJ) actuator in a single-pulse mode is studied experimentally. Except for schlieren images of the interaction process of SPJ with the flow field, a dynamic pressure measurement method is also used in the analysis of shock wave control. In a typical experimental case, under the control of single-pulsed SPJ, the characteristic of ramp shock changes from “short-term local upstream motion” in the initial stage to “long-term whole downstream motion” in the later stage. The angle and position of the ramp shock changes significantly in the whole control process. In addition, the dynamic pressure measurement result shows that the ramp pressure is reduced by a maximum of 79% compared to that in the base flow field, which indicates that the ramp shock is significantly weakened by SPJ. The effects of some parameters on the control effect of SPJ on the ramp shock are investigated and analyzed in detail. The increase in discharge capacitance helps to improve the control effect of SPJ on the ramp shock. However, the control effect of the SPJ actuator with medium exit diameter is better than that with a too small or too large one. In addition, when the SPJ exit is located in the separation zone and outside, the change in the ramp shock shows significant differences, but the control effect in the case of medium ramp distance is better when the SPJ exit is located outside the separation zone. Full article
(This article belongs to the Special Issue Advances in Plasma Diagnostics and Applications)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Schematic diagram of KD-2 supersonic wind tunnel.</p> Full article ">Figure 2
<p>Schematic diagram of experimental model; (<b>a</b>) experimental model installation; (<b>b</b>) SparkJet (SPJ) actuator section view.</p> Full article ">Figure 3
<p>Interaction process between SPJ and the supersonic crossflow near the ramp in case1.</p> Full article ">Figure 4
<p>Change curve of the ramp shock tail angle with time during the recovery process.</p> Full article ">Figure 5
<p>Change curves of discharge voltage and ramp wall pressure with time in case1.</p> Full article ">Figure 6
<p>Comparison of the flow field evolution process with different discharge capacitance: (<b>a</b>) case1—640 nF, (<b>b</b>) case2—320 nF and (<b>c</b>) case3—80 nF.</p> Full article ">Figure 7
<p>Change curves of ramp pressure with different discharge capacitances.</p> Full article ">Figure 8
<p>Comparison of the flow field evolution process with different exit diameters: (<b>a</b>) case4—1.5 mm, (<b>b</b>) case5—5 mm, (<b>c</b>) case6—11 mm.</p> Full article ">Figure 9
<p>Change curves of ramp pressure with different exit diameter.</p> Full article ">Figure 10
<p>Comparison of the flow field evolution process when SPJ exit is in the separation zone and outside: (<b>a</b>) case7—in the separation zone, (<b>b</b>) case5—outside the separation zone.</p> Full article ">Figure 11
<p>Comparison of the flow field evolution process when SPJ exit is outside the separation zone at different ramp distances: (<b>a</b>) case10—90 mm, (<b>b</b>) case9—70 mm, (<b>c</b>) case1—50 mm, (<b>d</b>) case8—30 mm.</p> Full article ">Figure 12
<p>Change curves of ramp pressure with different ramp distances.</p> Full article ">
30 pages, 884 KiB  
Review
A Review of Process Systems Engineering (PSE) Tools for the Design of Ionic Liquids and Integrated Biorefineries
by Nishanth G. Chemmangattuvalappil, Denny K. S. Ng, Lik Yin Ng, Jecksin Ooi, Jia Wen Chong and Mario R. Eden
Processes 2020, 8(12), 1678; https://doi.org/10.3390/pr8121678 - 18 Dec 2020
Cited by 18 | Viewed by 5084
Abstract
In this review paper, a brief overview of the increasing applicability of Process Systems Engineering (PSE) tools in two research areas, which are the design of ionic liquids and the design of integrated biorefineries, is presented. The development and advances of novel computational [...] Read more.
In this review paper, a brief overview of the increasing applicability of Process Systems Engineering (PSE) tools in two research areas, which are the design of ionic liquids and the design of integrated biorefineries, is presented. The development and advances of novel computational tools and optimization approaches in recent years have enabled these applications with practical results. A general introduction to ionic liquids and their various applications is presented followed by the major challenges in the design of optimal ionic liquids. Significant improvements in computational efficiency have made it possible to provide more reliable data for optimal system design, minimize the production cost of ionic liquids, and reduce the environmental impact caused by such solvents. Hence, the development of novel computational tools and optimization tools that contribute to the design of ionic liquids have been reviewed in detail. A detailed review of the recent developments in PSE applications in the field of integrated biorefineries is then presented. Various value-added products could be processed by the integrated biorefinery aided with applications of PSE tools with the aim of enhancing the sustainability performance in terms of economic, environmental, and social impacts. The application of molecular design tools in the design of integrated biorefineries is also highlighted. Major developments in the application of ionic liquids in integrated biorefineries have been emphasized. This paper is concluded by highlighting the major opportunities for further research in these two research areas and the areas for possible integration of these research fields. Full article
(This article belongs to the Special Issue Process Systems Engineering Tools for the Design of Ionic Liquids and Integrated Biorefineries)
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<p>The integrated biorefinery concept.</p> Full article ">Figure 2
<p>General framework of ionic liquid design via a computer-aided molecular design (CAMD) approach.</p> Full article ">
16 pages, 3395 KiB  
Article
VectorDisk: A Microfluidic Platform Integrating Diagnostic Markers for Evidence-Based Mosquito Control
by Sebastian Hin, Desirée Baumgartner, Mara Specht, Jan Lüddecke, Ehsan Mahmodi Arjmand, Benita Johannsen, Larissa Schiedel, Markus Rombach, Nils Paust, Felix von Stetten, Roland Zengerle, Nadja Wipf, Pie Müller, Konstantinos Mavridis, John Vontas and Konstantinos Mitsakakis
Processes 2020, 8(12), 1677; https://doi.org/10.3390/pr8121677 - 18 Dec 2020
Cited by 7 | Viewed by 3186
Abstract
Effective mosquito monitoring relies on the accurate identification and characterization of the target population. Since this process requires specialist knowledge and equipment that is not widely available, automated field-deployable systems are highly desirable. We present a centrifugal microfluidic cartridge, the VectorDisk, which integrates [...] Read more.
Effective mosquito monitoring relies on the accurate identification and characterization of the target population. Since this process requires specialist knowledge and equipment that is not widely available, automated field-deployable systems are highly desirable. We present a centrifugal microfluidic cartridge, the VectorDisk, which integrates TaqMan PCR assays in two feasibility studies, aiming to assess multiplexing capability, specificity, and reproducibility in detecting disk-integrated vector-related assays. In the first study, pools of 10 mosquitoes were used as samples. We tested 18 disks with 27 DNA and RNA assays each, using a combination of multiple microfluidic chambers and detection wavelengths (geometric and color multiplexing) to identify mosquito and malaria parasite species as well as insecticide resistance mechanisms. In the second study, purified nucleic acids served as samples to test arboviral and malaria infective mosquito assays. Nine disks were tested with 14 assays each. No false positive results were detected on any of the disks. The coefficient of variation in reproducibility tests was <10%. The modular nature of the platform, the easy adaptation of the primer/probe panels, the cold chain independence, the rapid (2–3 h) analysis, and the assay multiplexing capacity are key features, rendering the VectorDisk a potential candidate for automated vector analysis. Full article
(This article belongs to the Special Issue Advances in Microfluidics Technology for Diagnostics and Detection)
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Figure 1
<p>Schematic workflow for manual preparation of mosquito samples prior to VectorDisk tests during the Vector Study.</p> Full article ">Figure 2
<p>Schematic workflow of testing the three nucleic acid (NA) samples in the VectorDisk during the NA Study. ‘PF-INF’ represents the mixture of <span class="html-italic">P. falciparum</span> DNA + <span class="html-italic">P. falciparum</span> infective stage RNA.</p> Full article ">Figure 3
<p>The VectorDisk design where the main unit operations are indicated (<b>A</b>–<b>F</b>). The structure G has the role of stiffening in order to prevent the foil disk from bending. The design was the same for both the Vector- and the NA-Studies. What differed was the type of inserted sample, and the assay panel. ‘Ch.1, 2, …’ refers to the VectorDisk reaction chambers.</p> Full article ">Figure 4
<p>(<b>a</b>) The LabDisk Player instrument used in the two studies. (<b>b</b>) Pipetting the sample (diluted lysate or purified nucleic acid (NA)) into the VectorDisk.</p> Full article ">Figure 5
<p>Indicative LabDisk real-time RT-PCR data acquired for the semi-quantitative analysis of mosquito samples in VectorDisk #D11, as one representative out of the 18 disks, from all three channels green (<b>a</b>), yellow (<b>b</b>), and red (<b>c</b>). DNA and RNA assays are shown in solid and dashed lines, respectively. The threshold was set to be the <span class="html-italic">x</span>-axis itself.</p> Full article ">Figure 6
<p>Representative LabDisk real-time PCR, acquired from the analysis of purified RNA for the various targets of the NA Study. (<b>a</b>) <span class="html-italic">Pf</span> species ID (DNA); (<b>b</b>) <span class="html-italic">Pf</span> infective stage (RNA); (<b>c</b>) ZIKV (RNA); (<b>d</b>) WNV-Lineage 1 (RNA). Each VectorDisk graph has two curves because each assay was included in two reaction chambers per disk (indicated in the figure legends).</p> Full article ">Figure 6 Cont.
<p>Representative LabDisk real-time PCR, acquired from the analysis of purified RNA for the various targets of the NA Study. (<b>a</b>) <span class="html-italic">Pf</span> species ID (DNA); (<b>b</b>) <span class="html-italic">Pf</span> infective stage (RNA); (<b>c</b>) ZIKV (RNA); (<b>d</b>) WNV-Lineage 1 (RNA). Each VectorDisk graph has two curves because each assay was included in two reaction chambers per disk (indicated in the figure legends).</p> Full article ">
12 pages, 256 KiB  
Article
Pharmacoeconomic Analysis of Hemophilia Care in Romania
by Petre Serban, Brigitha Vlaicu, Margit Serban, Cristina Emilia Ursu, Adina Traila, Cristian Jinca, Jenel Marian Patrascu, Daniel Andrei, Andrei Kozma and Teodora Smaranda Arghirescu
Processes 2020, 8(12), 1676; https://doi.org/10.3390/pr8121676 - 18 Dec 2020
Cited by 1 | Viewed by 2543
Abstract
Hemophilia, a congenital X linked disease, has the serious burden of bleeding, requiring life-long replacement with coagulation factors (CF). In the present day, there is a continuously improving treatment for this condition. Objective: Our observational, cross-sectional study aims at finding out whether a [...] Read more.
Hemophilia, a congenital X linked disease, has the serious burden of bleeding, requiring life-long replacement with coagulation factors (CF). In the present day, there is a continuously improving treatment for this condition. Objective: Our observational, cross-sectional study aims at finding out whether a prophylactic replacement with CF is affordable from the point of view of its cost-effectiveness in our country. Material and methods: A cohort of 122 persons with hemophilia were included in this patient-reported outcome survey, and they answered a questionnaire consisting of 56 items, focused on 4 domains—socio-demographic, medical, quality of health/life and cost/cost-effectiveness. Results and discussion: The markers for quality of health/life were correlated with the direct and indirect costs of care, comparing subgroup 1 of patients with prophylactic vs. subgroup 2 with on-demand replacement. Based on the incremental quality adjusted life years and the incremental costs, we calculated the incremental cost-effectiveness ratio (ICER) proving that prophylaxis is more cost-effective than on-demand replacement on a long time basis. Conclusions: The ICER is a threshold recommending the reimbursement of costs for a life-long prophylactic replacement in our country. Full article
(This article belongs to the Special Issue Pharmaceutical Development and Bioavailability Analysis)
14 pages, 2904 KiB  
Article
Experimental Study on the Flow and Heat Transfer of Graphene-Based Lubricants in a Horizontal Tube
by Zhongpan Cai, Maocheng Tian and Guanmin Zhang
Processes 2020, 8(12), 1675; https://doi.org/10.3390/pr8121675 - 18 Dec 2020
Cited by 6 | Viewed by 2244
Abstract
To improve the heat transfer characteristics of lubricant, graphene-based lubricants were prepared by adding graphene particles, due to its advantages of excellent thermal conductivity and two-dimensional sheet structure. In the present study, its physical properties were measured. A flow heat transfer experiment platform [...] Read more.
To improve the heat transfer characteristics of lubricant, graphene-based lubricants were prepared by adding graphene particles, due to its advantages of excellent thermal conductivity and two-dimensional sheet structure. In the present study, its physical properties were measured. A flow heat transfer experiment platform was built to study the flow and heat transfer characteristics of the graphene lubricating oil in a horizontal circular tube. The results show that the graphene lubricant prepared using a two-step approach had good stability, and the dispersibility was good without the agglomeration phenomenon, according to measurements undertaken using an electron microscope and centrifuge. The thermal conductivity and viscosity of graphene lubricant increased with the increase of the graphene concentration, and the thermal conductivity of graphene lubricant with the same concentration decreased with the increase of temperature. When the concentration was equal, the convective heat transfer Nusselt number (Nu) of graphene lubricant increased with the increase of Reynolds number (Re). When Re was equal, the convective heat transfer Nu increased with the increase of graphene particle concentration, and the maximum Nu increased by 40%. Full article
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<p>SEM image of graphene.</p> Full article ">Figure 2
<p>The images of prepared nanofluid samples under multifunctional stereomicroscope.</p> Full article ">Figure 3
<p>Separation images of graphene lubricant oil at different centrifugal speeds.</p> Full article ">Figure 4
<p>Thermal conductivity of prepared nanofluid samples with different mass fraction.</p> Full article ">Figure 5
<p>Thermal conductivity of prepared nanofluid samples at different temperatures.</p> Full article ">Figure 6
<p>Viscosity of prepared nanofluid samples at different temperatures.</p> Full article ">Figure 7
<p>Specific heat capacity of prepared nanofluid samples at different temperature.</p> Full article ">Figure 8
<p>Schematic diagram of the experimental setup.</p> Full article ">Figure 9
<p>Pressure drop of prepared nanofluid samples at different Reynolds numbers.</p> Full article ">Figure 10
<p>Wall temperature for different samples along the tube length at different flow rates: (<b>a</b>) flow rate u = 0.35 m/s; (<b>b</b>) flow rate u = 0.50 m/s.</p> Full article ">Figure 11
<p>Local heat transfer coefficient for different samples along the tube length at different flow rates: (<b>a</b>) flow rate u = 0.35 m/s; (<b>b</b>) flow rate u = 0.50 m/s.</p> Full article ">Figure 12
<p>Heat transfer coefficient of prepared nanofluid samples at different velocities.</p> Full article ">Figure 13
<p>Nusselt number of prepared nanofluid samples at different Reynolds numbers.</p> Full article ">
14 pages, 2179 KiB  
Article
Antifungal Effect of Volatile Organic Compounds from Bacillus velezensis CT32 against Verticillium dahliae and Fusarium oxysporum
by Xinxin Li, Xiuhong Wang, Xiangyuan Shi, Baoping Wang, Meiping Li, Qi Wang and Shengwan Zhang
Processes 2020, 8(12), 1674; https://doi.org/10.3390/pr8121674 - 18 Dec 2020
Cited by 52 | Viewed by 4642
Abstract
The present study focuses on the inhibitory effect of volatile metabolites released by Bacillus velezensis CT32 on Verticillium dahliae and Fusarium oxysporum, the causal agents of strawberry vascular wilt. The CT32 strain was isolated from maize straw compost tea and identified as [...] Read more.
The present study focuses on the inhibitory effect of volatile metabolites released by Bacillus velezensis CT32 on Verticillium dahliae and Fusarium oxysporum, the causal agents of strawberry vascular wilt. The CT32 strain was isolated from maize straw compost tea and identified as B. velezensis based on 16S rRNA gene sequence analysis. Bioassays conducted in sealed plates revealed that the volatile organic compounds (VOCs) produced by the strain CT32 possessed broad-spectrum antifungal activity against eight phytopathogenic fungi. The volatile profile of strain CT32 was obtained by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). A total of 30 volatile compounds were identified, six of which have not previously been detected in bacteria or fungi: (Z)-5-undecene, decyl formate, 2,4-dimethyl-6-tert-butylphenol, dodecanenitrile, 2-methylpentadecane and 2,2’,5,5’-tetramethyl-1,1’-biphenyl. Pure compounds were tested in vitro for their inhibitory effect on the mycelial growth of V. dahliae and F. oxysporum. Decanal, benzothiazole, 3-undecanone, 2-undecanone, 2-undecanol, undecanal and 2,4-dimethyl-6-tert-butylphenol showed high antifungal activity, with benzothiazole and 2,4-dimethyl-6-tert-butylphenol being the most potent compounds. These results indicate that the VOCs produced by B. velezensis CT32 have the potential to be used as a biofumigant for management of vascular wilt pathogens. Full article
(This article belongs to the Special Issue Advances in Microbial Fermentation Processes)
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<p>Inhibitory effect of volatile organic compounds (VOCs) produced by strain CT32 on the mycelial growth of 8 plant pathogenic fungi. Values with different lowercase letters are significantly different according to Duncan’s multiple range test at the 0.05 level.</p> Full article ">Figure 2
<p>Effect of VOCs emitted by strain CT32 on the growth of 8 phytopathogenic fungi in vitro. In the sealed plates test, fungi in the control groups were cultured on potato dextrose agar (PDA) medium. The mycelial growth of fungi in the treatment groups was suppressed upon exposure to volatiles emitted by strain CT32. (<b>a</b>) <span class="html-italic">V. dahliae</span>; (<b>b</b>) <span class="html-italic">F. oxysporum</span> f. sp. <span class="html-italic">fragariae</span>; (<b>c</b>) <span class="html-italic">F. oxysporum</span> f. sp. <span class="html-italic">niveum</span>; (<b>d</b>) <span class="html-italic">F. oxysporum</span> f. sp. <span class="html-italic">cucumerinum</span>; (<b>e</b>) <span class="html-italic">B. cinerea</span>; (<b>f</b>) <span class="html-italic">T. cucumeris</span>; (<b>g</b>) <span class="html-italic">G. cingulata</span>; (<b>h</b>) <span class="html-italic">B. dothidea</span>.</p> Full article ">Figure 3
<p>(<b>a</b>) Total ion chromatogram of VOCs from uninoculated nutrient agar (NA) medium; (<b>b</b>) total ion chromatogram of VOCs from strain CT32.</p> Full article ">Figure 4
<p>(<b>a</b>) Light micrograph of strain CT32 cell morphology; (<b>b</b>) transmission electron microscopy image of strain CT32 endospore.</p> Full article ">Figure 5
<p>Neighbor-joining (NJ) tree based on 16S rRNA gene sequences, highlighting the phylogenetic relationship of strain CT32 to other strain types of the genus <span class="html-italic">Bacillus</span>. Bootstrap values (1000 replications) greater than 50% are given at branch points. Scale bar = 0.02 substitutions per nucleotide position.</p> Full article ">
14 pages, 2859 KiB  
Article
Methanol Synthesis with Steel-Mill Gases: Simulation and Practical Testing of Selected Gas Utilization Scenarios
by Kai Girod, Heiko Lohmann, Stefan Schlüter and Stefan Kaluza
Processes 2020, 8(12), 1673; https://doi.org/10.3390/pr8121673 - 17 Dec 2020
Cited by 7 | Viewed by 3776
Abstract
The utilization of CO2-containing steel-mill gases for synthesis of methanol was investigated. Four different scenarios with syngas derived from steel-mill gases were considered. A process model for an industrial methanol production including gas recirculation was applied to provide realistic conditions for [...] Read more.
The utilization of CO2-containing steel-mill gases for synthesis of methanol was investigated. Four different scenarios with syngas derived from steel-mill gases were considered. A process model for an industrial methanol production including gas recirculation was applied to provide realistic conditions for catalyst performance tests. A long-term test series was performed in a close-to-practice setup to demonstrate the stability of the catalyst. In addition, the experimental results were used to discuss the quality of the simulation results. Kinetic parameters of the reactor model were fitted. A comparison of two different kinetic approaches and the experimental results revealed which approach better fits CO-rich or CO2-rich steel-mill gases. Full article
(This article belongs to the Special Issue Heterogeneous Catalysts for CO2 Valorisation)
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<p>Typical gas composition in vol. % of steel-mill gases.</p> Full article ">Figure 2
<p>Flow scheme of the applied process model.</p> Full article ">Figure 3
<p>Basic flow scheme of the test setup.</p> Full article ">Figure 4
<p>(<b>a</b>) Fixed-bed reactor with fibre-optic temperature measurement and (<b>b</b>) photo of the test setup.</p> Full article ">Figure 5
<p>Carbon efficiency and reactor productivity (<b>a</b>), and N<sub>2</sub>-amount at the reactor inlet (<b>b</b>) as a function of the recycle ratio (RR).</p> Full article ">Figure 6
<p>Axial temperature profile of the gas utilization scenarios at a recycle ratio (RR) of 7.</p> Full article ">Figure 7
<p>Simulation results of four gas-utilization scenarios.</p> Full article ">Figure 8
<p>Carbon efficiency and methanol productivity for the pure CO<sub>2</sub> scenario as a function of the recycle ratio (RR).</p> Full article ">Figure 9
<p>Practical test results of the considered case scenarios (<b>a</b>) and the order of the performed tests (<b>b</b>).</p> Full article ">Figure 10
<p>Axial temperature profile measured at 9 equidistant measurement points inside the catalytic fixed bed of 60 cm total length.</p> Full article ">Figure 11
<p>Comparison between experimental productivity and the process simulation results according to the Graaf kinetic with catalyst diffusion limitation pre-factors adapted to an industrial catalyst (<b>a</b>) and comparison between the experimental results and simulation results according to two different kinetic approaches without lcatalyst diffusion limitation pre-factors (<b>b</b>).</p> Full article ">
23 pages, 4700 KiB  
Article
Permeate Flux Control in SMBR System by Using Neural Network Internal Model Control
by Norhaliza Abdul Wahab, Nurazizah Mahmod and Ramon Vilanova
Processes 2020, 8(12), 1672; https://doi.org/10.3390/pr8121672 - 17 Dec 2020
Cited by 5 | Viewed by 2526
Abstract
This paper presents a design of a data-driven-based neural network internal model control for a submerged membrane bioreactor (SMBR) with hollow fiber for microfiltration. The experiment design is performed for measurement of physical parameters from an actuator input (permeate pump voltage), which gives [...] Read more.
This paper presents a design of a data-driven-based neural network internal model control for a submerged membrane bioreactor (SMBR) with hollow fiber for microfiltration. The experiment design is performed for measurement of physical parameters from an actuator input (permeate pump voltage), which gives the information (outputs) of permeate flux and trans-membrane pressure (TMP). The palm oil mill effluent is used as an influent preparation to depict fouling phenomenon in the membrane filtration process. From the experiment, membrane fouling potential is observed from flux decline pattern, with a rapid increment of TMP (above 200 mbar). Membrane fouling is a complex process and the available models in literature are not designed for control system (filtration performance). Therefore, this work proposes an aeration fouling control strategy to measure the filtration performance. The artificial neural networks (Feed-Forward Neural Network—FFNN, Radial Basis Function Neural Network—RBFNN and Nonlinear Autoregressive Exogenous Neural Network—NARXNN) are used to model dynamic behaviour of flux and TMP. In this case, only flux is used in closed loop control application, whereby the TMP effect is used for monitoring. The simulation results show that reliable prediction of membrane fouling potential is obtained. It can be observed that almost all the artificial neural network (ANN) models have similar shape with the actual data set, with the highest accuracy of more than 90% for both RBFNN and NARXN. The RBFNN is preferable due to simple structure of the network. In the control system, the RBFNN IMC depicts the highest closed loop performance with only 3.75 s (settling time) for setpoint changes when compared with other controllers. In addition, it showed fast performance in disturbance rejection with less overshoot. In conclusion, among the different neural network tested configurations the one based on radial basis function provides the best performance with respect to prediction as well as control performance. Full article
(This article belongs to the Special Issue Optimization and Control of Integrated Water Systems)
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<p>Workflow of the method.</p> Full article ">Figure 2
<p>The schematic layout of th submerged Membrane Bioreactor (MBR) pilot plant: <b>a</b>—inlet stream, <b>b</b>—aeration stream, <b>c</b>—backwash stream, <b>d</b>—permeate stream.</p> Full article ">Figure 3
<p>(<b>a</b>) Submerged MBR bench scale plant; (<b>b</b>) Hollow Fibre (HF)-Membrane (with three membrane modules).</p> Full article ">Figure 4
<p>Input and output data for the SMBR filtration process: The input is the permeate pump voltage while the outputs are the flux and TMP. The aeration airflow during filtration is set around 6 to 8 L per minute (LPM) to maintain high intensity of bubble flow in cleaning the membrane.</p> Full article ">Figure 5
<p>Feed-Forward Neural Network (FFNN) procedure.</p> Full article ">Figure 6
<p>Radial Basis Function Neural Network (RBFNN) structure.</p> Full article ">Figure 7
<p>RBFNN procedure.</p> Full article ">Figure 8
<p>Nonlinear Autoregressive Exogenous Neural Network (NARXNN) procedure.</p> Full article ">Figure 9
<p>Neural Network Internal Model Control (NNIMC) inverse model training.</p> Full article ">Figure 10
<p>Conventional IMC (C-IMC) Neural Network block diagram.</p> Full article ">Figure 11
<p>Modified IMC Neural Network block diagram.</p> Full article ">Figure 12
<p>Model and real-time open-loop flux responses for constant input voltage.</p> Full article ">Figure 13
<p>Training models for (<b>a</b>) flux; (<b>b</b>) trans-membrane pressure (TMP).</p> Full article ">Figure 14
<p>Testing models for (<b>a</b>) flux; (<b>b</b>) TMP.</p> Full article ">Figure 15
<p>Input–output step responses performance; (<b>a</b>) voltage, (<b>b</b>) flux, (<b>c</b>) TMP.</p> Full article ">Figure 15 Cont.
<p>Input–output step responses performance; (<b>a</b>) voltage, (<b>b</b>) flux, (<b>c</b>) TMP.</p> Full article ">Figure 16
<p>30% step disturbance; (<b>a</b>) amplitude of 6 L/m<sup>2</sup>h, (<b>b</b>) flux performance.</p> Full article ">Figure 16 Cont.
<p>30% step disturbance; (<b>a</b>) amplitude of 6 L/m<sup>2</sup>h, (<b>b</b>) flux performance.</p> Full article ">Figure 17
<p>(<b>a</b>) Flux of setpoint change; (<b>b</b>) voltage of setpoint change; (<b>c</b>) TMP effect of the set point change.</p> Full article ">Figure 17 Cont.
<p>(<b>a</b>) Flux of setpoint change; (<b>b</b>) voltage of setpoint change; (<b>c</b>) TMP effect of the set point change.</p> Full article ">
12 pages, 3940 KiB  
Article
New Design of the Reversible Jet Fan
by Miroslav H. Benišek, Đorđe S. Čantrak, Dejan B. Ilić and Novica Z. Janković
Processes 2020, 8(12), 1671; https://doi.org/10.3390/pr8121671 - 17 Dec 2020
Cited by 4 | Viewed by 4529
Abstract
This paper presents two designs of the axial reversible jet fan, with the special focus on the impeller. The intention was to develop a reversible axial jet fan which operates in the same way in both rotating directions while generating thrust as high [...] Read more.
This paper presents two designs of the axial reversible jet fan, with the special focus on the impeller. The intention was to develop a reversible axial jet fan which operates in the same way in both rotating directions while generating thrust as high as possible. The jet fan model with the outer diameter 499.2 ± 0.1 mm and ten adjustable blades is the same, while it is in-built in two different casings. The first construction is a cylindrical casing, while the second one is profiled as a nozzle. Thrust, volume flow rate, consumed power and ambient conditions were measured after the international standard ISO 13350. Results for both constructions are presented for three impeller blade angles: 28°, 31° and 35°, and rotation speed in the interval n = 400 to 2600 rpm. The smallest differences in thrust, depending on the fan rotation direction, as well as the highest thrust are achieved for the first design with the cylindrical casing and blade angle at the outer diameter of 35°. Therefore, it was shown that fan casing significantly influences jet fan characteristics. In addition, the maximum thrust value and its independence of the flow direction is experimentally obtained for the angle of 39° in the cylindrical casing. Full article
(This article belongs to the Special Issue CFD Based Researches and Applications for Fluid Machinery and Fluid Device)
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<p>(<b>a</b>) Geometry of the impeller symmetrical blade and (<b>b</b>) Reversible jet axial fan with specified normal and reverse flow directions.</p> Full article ">Figure 1 Cont.
<p>(<b>a</b>) Geometry of the impeller symmetrical blade and (<b>b</b>) Reversible jet axial fan with specified normal and reverse flow directions.</p> Full article ">Figure 2
<p>Developed axial fan impeller with its casing and AC electric motor.</p> Full article ">Figure 3
<p>The second construction of the casing: (<b>a</b>) at the thrust measurement table and (<b>b</b>) nozzle geometry.</p> Full article ">Figure 4
<p>Thrust measurement table in the laboratory: (<b>a</b>) 3D model for calibration and (<b>b</b>) real model.</p> Full article ">Figure 5
<p>Connection of the force transducer with wheel chair: <b>1</b>—force transducer, <b>2</b>—force transmitter carrier, <b>3</b>—measuring tape, <b>4</b>—wheel chair, <b>5</b>—axial fan, <b>6</b>—rails, <b>7</b>—steel plate for connection of rails with wheel chair loaded with reversible jet fan and <b>8</b>—fundament.</p> Full article ">Figure 6
<p>Reversible jet fan characteristics in the function of the fan rotation speed and angle <span class="html-italic">β<sub>Ra</sub></span> for both flow directions: (<b>a</b>) volume flow rate, (<b>b</b>) internal consumed power, (<b>c</b>) thrust and (<b>d</b>) efficiency.</p> Full article ">Figure 7
<p>Reversible jet fan characteristics in the function of the fan rotation speed for both flow directions and angle <span class="html-italic">β<sub>Ra</sub></span> = 39°: (<b>a</b>) volume flow rate, (<b>b</b>) internal consumed power, (<b>c</b>) thrust and (<b>d</b>) efficiency.</p> Full article ">Figure 8
<p>Comparison of the fan thrust in cylindrical (1) and nozzle (2) profiled casings for various angles <span class="html-italic">β<sub>Ra</sub></span> and rotational directions (I-normal and II-reversible flow directions) in the function of the fan rotation speed: (<b>a</b>) 28°, (<b>b</b>) 31° and (<b>c</b>) 35°.</p> Full article ">
11 pages, 1959 KiB  
Article
Evaluation of Oxidative Stress Parameters in Healthy Saddle Horses in Relation to Housing Conditions, Presence of Stereotypies, Age, Sex and Breed
by Luca Molinari, Giuseppina Basini, Roberto Ramoni, Simona Bussolati, Raffaella Aldigeri, Stefano Grolli, Simone Bertini and Fausto Quintavalla
Processes 2020, 8(12), 1670; https://doi.org/10.3390/pr8121670 - 17 Dec 2020
Cited by 6 | Viewed by 2883
Abstract
Oxidative stress plays an important role in the development of many horse diseases and it has been shown that housing has important implications for the psychophysical well-being of horses. The aim of this study is to determine if there are any differences between [...] Read more.
Oxidative stress plays an important role in the development of many horse diseases and it has been shown that housing has important implications for the psychophysical well-being of horses. The aim of this study is to determine if there are any differences between the redox status in horses in relation to housing conditions. The four housing conditions analyzed were: single box, without external access and without contact (Cat A), single box with external access and possibility of partial contact (Cat B), group housing with box and large paddock (Cat C), pasture with more than 7 horses and the possibility of green forage for the whole year (Cat D). A group of 117 healthy horses were selected in several private stables in Northern Italy. All subjects treated with any type of drug were excluded. At the end of the enrollment, the 117 selected horses were divided into the four housing categories. Stereotypies were highest in the group of horses in single box, without external access and without contact (Cat A). Oxidative stress was evaluated by testing plasma or serum samples for the following parameters: superoxide anion (WST), nitric oxide (NO), reactive oxygen species (d-ROMs), ferric reducing ability of plasma (FRAP), and the activity of superoxide dismutase (SOD). Simultaneously with the blood sampling, the owners completed a questionnaire with all the management aspects of the horse (signaling, feeding, equestrian activity, vaccinations, foot management etc.). The statistical evaluation was carried out based on the categories previously described, on the presence and absence of stereotypies and on some signaling data obtained from the questionnaire. There were no significant differences in the parameters analyzed between the categories. No significant redox status differences were detected based on the presence or absence of stereotypies. Interestingly, when the age was introduced as selection (<14 and >14 years old) parameter inside the categories, statistical significance was observed for some of the stress markers considered. Finally, independently of the housing conditions, the horses of the most two represented breeds exhibited different values of FRAP. All these aspects are commented in the discussion. Full article
(This article belongs to the Special Issue Advances of Redox Status in Disease)
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<p>Distribution of horses with and without stereotypes in the various housing conditions. * means <span class="html-italic">p</span> &lt; 0.05.</p> Full article ">Figure 2
<p>Box plots of the redox markers of the 117 horses enrolled, considering the different housing conditions (green), breed (pink), age (cyan), stereotypy (yellow) and gender. The data were analyzed by Kruskal–Wallis test.</p> Full article ">Figure 3
<p>Box plots of the ferric reducing ability of plasma (FRAP) (<b>A</b>) and superoxide anion (WST) (<b>B</b>) values of the &lt;14 and &gt;14-years-old horses belonging to housing category A. The data have been analyzed by Mann–Whitney test.</p> Full article ">Figure 4
<p>(<b>A</b>): Box plots of the FRAP values of the &lt;14-years-old horses of the different housing categories. (<b>B</b>): Box plot of the WST values of the &gt;14 years old horses belonging to the different housing conditions. The comparisons were realized by Mann-Whitney test.</p> Full article ">
11 pages, 2921 KiB  
Article
The Supervision of Dough Fermentation Using Image Analysis Complemented by a Continuous Discrete Extended Kalman Filter
by Olivier Paquet-Durand, Viktoria Zettel, Abdolrahim Yousefi-Darani and Bernd Hitzmann
Processes 2020, 8(12), 1669; https://doi.org/10.3390/pr8121669 - 17 Dec 2020
Cited by 4 | Viewed by 2485
Abstract
Dough fermentation is an important step during the preparation of fermented baking goods. For the supervision of dough fermentation, a continuous-discrete extended Kalman filter was applied, which uses an image analysis system as the measurement. By estimation a fixed number of gas bubbles [...] Read more.
Dough fermentation is an important step during the preparation of fermented baking goods. For the supervision of dough fermentation, a continuous-discrete extended Kalman filter was applied, which uses an image analysis system as the measurement. By estimation a fixed number of gas bubbles inside the dough, the radius of an average bubble was determined. A mathematical dough model was used by the extended Kalman filter to estimate the radius of the average bubble, the CO2 concentration of the non-gas dough phase and the number of CO2 molecules in the average bubble. During a fermentation of 50 min, the extended Kalman filter estimated that the average radius increased from 50 µm to 127 µm, the CO2 concentration in the non-gas dough increased to 23 mol/m³, and the CO2 amount in the bubble increased from 0.1 × 10−10 to 4 × 10−10 mol. Also, the specific CO2 production rate was estimated to be in the range from 1.5 × 10−3 to more than 4 × 10−3 mol·m³/kg/s. The advantages of an extended Kalman filter for the supervision of the dough fermentation process are discussed. Full article
(This article belongs to the Special Issue Redesign Processes in the Age of the Fourth Industrial Revolution)
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<p>Bubble radii calculated by the imaging system compared to the values estimated by the extended Kalman filter as well as simulated values.</p> Full article ">Figure 2
<p>Simulated and Kalman estimation of the amount of CO<sub>2</sub> in a bubble.</p> Full article ">Figure 3
<p>Simulated and Kalman estimation of the CO<sub>2</sub> concentration in non-gaseous dough.</p> Full article ">Figure 4
<p>Simulated and Kalman estimation of the specific CO<sub>2</sub> production rate.</p> Full article ">Figure 5
<p>Estimation error variance of the radius and the specific CO<sub>2</sub> production rate.</p> Full article ">Figure 6
<p>Estimation error of the CO<sub>2</sub> in non-gaseous dough and the amount of CO<sub>2</sub> in the bubble.</p> Full article ">Figure 7
<p>Estimated specific CO<sub>2</sub> production rate calculated during three runs of the extended Kalman filter with the same measurements but with different assumed yeast concentrations; the production rate was multiplied by 2 where the yeast concentration was considered to be 64 kg/m³; the production rate was divided by 2 where the yeast concentration was considered to be 16 kg/m³; the correct yeast concentration was 16 kg/m³.</p> Full article ">
13 pages, 1965 KiB  
Article
Inventory of MSWI Fly Ash in Switzerland: Heavy Metal Recovery Potential and Their Properties for Acid Leaching
by Wolfgang Zucha, Gisela Weibel, Mirjam Wolffers and Urs Eggenberger
Processes 2020, 8(12), 1668; https://doi.org/10.3390/pr8121668 - 17 Dec 2020
Cited by 13 | Viewed by 3673
Abstract
From the year 2021 on, heavy metals from Swiss municipal solid waste incineration (MSWI) fly ash (FA) must be recovered before landfilling. This is predominantly performed by acid leaching. As a basis for the development of defined recovery rates and for the implementation [...] Read more.
From the year 2021 on, heavy metals from Swiss municipal solid waste incineration (MSWI) fly ash (FA) must be recovered before landfilling. This is predominantly performed by acid leaching. As a basis for the development of defined recovery rates and for the implementation of the recovery process, the authorities and plant operators need information on the geochemical properties of FA. This study provides extended chemical and mineralogical characterization of all FA produced in 29 MSWI plants in Switzerland. Acid neutralizing capacity (ANC) and metallic aluminum (Al0) were additionally analyzed to estimate the effort for acid leaching. Results show that all FA samples are composed of similar constituents, but their content varies due to differences in waste input and incineration conditions. Based on their geochemical properties, the ashes could be divided into four types describing the leachability: very good (6 FA), good (10 FA), moderate (5 FA), and poor leaching potential (8 FA). Due to the large differences it is suggested that the required recovery rates are adjusted to the leaching potential. The quantity of heavy metals recoverable by acid leaching was estimated to be 2420 t/y Zn, 530 t/y Pb, 66 t/y Cu and 22 t/y Cd. Full article
(This article belongs to the Special Issue Advanced Technology of Waste Treatment)
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<p>Concentration distribution of selected chemical constituents in the 29 Swiss fly ash (FA) samples.</p> Full article ">Figure 2
<p>Distribution of the main mineral phases in Swiss FA in wt.%. Outliners are marked as circle.</p> Full article ">Figure 3
<p>Titration curve of selected FA samples (LS 10). The main plateaus are marked with a black line. The black arrow illustrates the big difference of acid that is required to achieve pH 2.</p> Full article ">Figure 4
<p>Boxplot of the acid neutralizing capacity (ANC) as amount mol H<sup>+</sup> to reach pH 2 at a L/S ratio of 10 and Al<sup>0</sup> in Swiss FA (n = 29).</p> Full article ">Figure 5
<p>Cluster tree of the FA samples according to their content of Zn and Al<sup>0</sup>, the ANC, and the amount of FA produced in 2016. The y-axis shows the distances between the calculated values and hence is a mathematical value that expresses the dissimilarity.</p> Full article ">Figure 6
<p>Average Zn and A<sup>l0</sup> concentration as well as average produced FA per plant and the average ANC for each cluster.</p> Full article ">
15 pages, 2679 KiB  
Article
The Dynamics of Globally Unstable Air-Helium Jets and Its Impact on Jet Mixing Intensity
by Agnieszka Pawlowska and Andrzej Boguslawski
Processes 2020, 8(12), 1667; https://doi.org/10.3390/pr8121667 - 17 Dec 2020
Cited by 4 | Viewed by 1794
Abstract
The paper presents experimental investigations of the low-density air-helium jets. The paper is aimed at the analysis of the flow conditions promoting the local absolute instability leading to global flow oscillations. A number of the test cases are analysed with a wide range [...] Read more.
The paper presents experimental investigations of the low-density air-helium jets. The paper is aimed at the analysis of the flow conditions promoting the local absolute instability leading to global flow oscillations. A number of the test cases are analysed with a wide range of the shear layer thickness showing conditions favorable for the global modes and also mixing intensity triggered by such a regime. It is shown that high mixing intensity is determined not only by the global regime but also by the vortex pairing process. The results are compared with a recently proposed universal scaling law for an onset into the global mode. The results turn out to be far from this scaling law and the reasons for such discrepancies are discussed. The measurements show also that if the shear layer at the nozzle exit is thin enough the global modes are suppressed. The mechanism leading to the global mode suppression under such conditions is carefully analysed. Full article
(This article belongs to the Special Issue Advances in the Chemical Mixing Process)
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Figure 1

Figure 1
<p>Sketch of the experimental rig.</p> Full article ">Figure 2
<p>(<b>a</b>) Mean and (<b>b</b>) fluctuating velocity profiles along the jet axis, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>7</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> <mn>5000</mn> </mrow> </semantics></math>.</p> Full article ">Figure 3
<p>Evolution of spectra of axial velocity fluctuations, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.9</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>7</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> <mn>5000</mn> </mrow> </semantics></math>: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>5</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>7</mn> </mrow> </semantics></math>, (<b>d</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>9</mn> </mrow> </semantics></math>.</p> Full article ">Figure 4
<p>(<b>a</b>) Mean and (<b>b</b>) fluctuating velocity profiles along the jet axis, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>7</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> </mrow> </semantics></math> 10,000.</p> Full article ">Figure 5
<p>Evolution of spectra of axial velocity fluctuations, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.9</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>7</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> </mrow> </semantics></math> 10,000: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>4</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>5</mn> </mrow> </semantics></math>.</p> Full article ">Figure 6
<p>Convective/absolute/global boundary. Linear stability theory results of Jendoubi and Strykowski [<a href="#B19-processes-08-01667" class="html-bibr">19</a>] and Boguslawski et al. [<a href="#B18-processes-08-01667" class="html-bibr">18</a>] compared with a universal scaling law of onset into the global mode proposed by Zhu et al. [<a href="#B14-processes-08-01667" class="html-bibr">14</a>].</p> Full article ">Figure 7
<p>(<b>a</b>) Mean and (<b>b</b>) fluctuating velocity profiles along the jet axis, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> <mn>5000</mn> </mrow> </semantics></math>.</p> Full article ">Figure 8
<p>Evolution of spectra of axial velocity fluctuations, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>25</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> <mn>5000</mn> </mrow> </semantics></math>: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>6</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>8</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>10</mn> </mrow> </semantics></math>.</p> Full article ">Figure 8 Cont.
<p>Evolution of spectra of axial velocity fluctuations, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>25</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> <mn>5000</mn> </mrow> </semantics></math>: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>6</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>8</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>10</mn> </mrow> </semantics></math>.</p> Full article ">Figure 9
<p>Evolution of spectra of axial velocity fluctuations, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>15</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> <mn>5000</mn> </mrow> </semantics></math>: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>4</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>6</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>8</mn> </mrow> </semantics></math>.</p> Full article ">Figure 10
<p>Evolution of spectra of axial velocity fluctuations, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>7</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> <mn>5000</mn> </mrow> </semantics></math>: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>4</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>5</mn> </mrow> </semantics></math>.</p> Full article ">Figure 11
<p>Evolution of spectra of axial velocity fluctuations, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>1</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> <mn>5000</mn> </mrow> </semantics></math>: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>4</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>5</mn> </mrow> </semantics></math>.</p> Full article ">Figure 12
<p>(<b>a</b>) Mean and (<b>b</b>) fluctuating velocity profiles along the jet axis, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> </mrow> </semantics></math> 10,000.</p> Full article ">Figure 13
<p>Evolution of spectra of axial velocity fluctuations, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>25</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> </mrow> </semantics></math> 10,000: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>4</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>6</mn> </mrow> </semantics></math>.</p> Full article ">Figure 14
<p>Evolution of spectra of axial velocity fluctuations, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>15</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> </mrow> </semantics></math> 10,000: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>4</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>6</mn> </mrow> </semantics></math>.</p> Full article ">Figure 15
<p>Evolution of spectra of axial velocity fluctuations, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>7</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> </mrow> </semantics></math> 10,000: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>4</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>6</mn> </mrow> </semantics></math>.</p> Full article ">Figure 15 Cont.
<p>Evolution of spectra of axial velocity fluctuations, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>7</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> </mrow> </semantics></math> 10,000: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>4</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>6</mn> </mrow> </semantics></math>.</p> Full article ">Figure 16
<p>Evolution of spectra of axial velocity fluctuations, <math display="inline"><semantics> <mrow> <mi>S</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>1</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>R</mi> <mi>e</mi> <mo>=</mo> </mrow> </semantics></math> 10,000: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>1</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>/</mo> <mi>D</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>.</p> Full article ">Figure 17
<p>Non-dimensional frequency as a function of the <math display="inline"><semantics> <mrow> <mi>D</mi> <mo>/</mo> <mi>θ</mi> </mrow> </semantics></math> parameter.</p> Full article ">Figure 18
<p>Experimental results vs. universal scaling law ([<a href="#B13-processes-08-01667" class="html-bibr">13</a>]).</p> Full article ">
17 pages, 7977 KiB  
Article
Electrochemical Mineralization of Ibuprofen on BDD Electrodes in an Electrochemical Flow Reactor: Numerical Optimization Approach
by Alejandro Regalado-Méndez, Martín Ruiz, José A. Hernández-Servín, Reyna Natividad, Rubi Romero, Mario E. Cordero, Carlos Estrada-Vázquez and Ever Peralta-Reyes
Processes 2020, 8(12), 1666; https://doi.org/10.3390/pr8121666 - 17 Dec 2020
Cited by 9 | Viewed by 3368
Abstract
Statistical analysis was applied to optimize the electrochemical mineralization of ibuprofen with two boron-doped diamond (BDD) electrodes in a continuous electrochemical flow reactor under recirculation batch mode. A central composite rotatable (CCR) experimental design was used to analyze the effect of initial pH [...] Read more.
Statistical analysis was applied to optimize the electrochemical mineralization of ibuprofen with two boron-doped diamond (BDD) electrodes in a continuous electrochemical flow reactor under recirculation batch mode. A central composite rotatable (CCR) experimental design was used to analyze the effect of initial pH (2.95–13.04), current intensity (2.66–4.34 A), and volumetric flow rate (0.16–1.84 L/min) and further optimized by response surface methodology (RSM) to obtain the maximum mineralization efficiency and the minimum specific energy consumption. A 91.6% mineralization efficiency (EM) of ibuprofen with a specific energy consumption (EC) of 4.36 KW h/g TOC within 7 h of treatment was achieved using the optimized operating parameters (pH0 = 12.29, I = 3.26 A, and Q of 1 L/min). Experimental results of RSM were fitted via a third-degree polynomial regression equation having the performance index determination coefficients (R2) of 0.8658 and 0.8468 for the EM and EC, respectively. The reduced root-mean-square error (RMSE) was 0.1038 and 0.1918 for EM and EC, respectively. This indicates an efficient predictive performance to optimize the operating parameters of the electrochemical flow reactor with desirability of 0.9999993. Besides, it was concluded that the optimized conditions allow to achieve a high percentage of ibuprofen mineralization (91.6%) and a cost of 0.002 USD $/L. Therefore, the assessed process is efficient for wastewater remediation.” Full article
(This article belongs to the Special Issue Control and Optimization of Wastewater Treatment Technology)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Experimental setup for the electrochemical mineralization of IBU in an Electrochemical Flow Reactor under recirculation batch mode.</p> Full article ">Figure 2
<p>(<b>a</b>) Predicted versus experimental values plot for <span class="html-italic">E<sub>M</sub></span> and (<b>b</b>) Predicted versus experimental values plot for <span class="html-italic">E<sub>C</sub></span>.</p> Full article ">Figure 3
<p>(<b>a</b>) Perturbation graphic for <span class="html-italic">η</span><sub>1</sub> and (<b>b</b>) Perturbation graphic for <span class="html-italic">η</span><sub>2</sub>.</p> Full article ">Figure 4
<p>(<b>a</b>) Contour plot for response <span class="html-italic">η</span><sub>1</sub> concerning pH<sub>0</sub> and <span class="html-italic">I</span>; (<b>b</b>) 3D plot for response <span class="html-italic">η</span><sub>1</sub> pH<sub>0</sub> and <span class="html-italic">I</span>; (<b>c</b>) Contour plot for response <span class="html-italic">η</span><sub>2</sub> concerning pH<sub>0</sub> and <span class="html-italic">I</span>; (<b>d</b>) 3D plot for response <span class="html-italic">η</span><sub>2</sub> pH<sub>0</sub> and <span class="html-italic">I</span>; (<b>e</b>) Optimal region plot, pH<sub>0</sub> versus <span class="html-italic">I</span>; (<b>f</b>) Bar chart of desirability. Plots (<b>a</b>) to (<b>b</b>) were edited at a volumetric flow rate of 1 L/min.</p> Full article ">Figure 5
<p>Decay kinetics of electrochemical mineralization of IBU.</p> Full article ">
14 pages, 2663 KiB  
Article
Evaluation of Direct Ultrasound-Assisted Extraction of Phenolic Compounds from Potato Peels
by Shusheng Wang, Amy Hui-Mei Lin, Qingyou Han and Qin Xu
Processes 2020, 8(12), 1665; https://doi.org/10.3390/pr8121665 - 17 Dec 2020
Cited by 24 | Viewed by 4048
Abstract
Potato peels (PPs) are generally considered as agriculture waste. The United States alone generates over one million tons of PPs a year. However, PPs contain valuable phenolic compounds with antioxidant activities. In this study, we evaluated the efficiency of ultrasound-assisted extraction techniques in [...] Read more.
Potato peels (PPs) are generally considered as agriculture waste. The United States alone generates over one million tons of PPs a year. However, PPs contain valuable phenolic compounds with antioxidant activities. In this study, we evaluated the efficiency of ultrasound-assisted extraction techniques in recovering antioxidants from PPs. These techniques included a direct ultrasound-assisted extraction (DUAE), an indirect ultrasound-assisted extraction (IUAE), and a conventional shaking extraction (CSE). Results of this study showed that DUAE was more effective in extracting phenolic compounds than IUAE and CSE. We also evaluated the factors affecting the yield of total phenolic compounds (TPC) in DUAE, including the temperature, time, acoustic power, ratio of solvent to solids, and size of PPs particles. TPC yield of DUAE was higher, and the extraction rate was faster than IUAE and CSE. Furthermore, TPC yield was strongly correlated to the temperature of the mixture of PPs suspension. SEM images revealed that the irradiation of ultrasound energy from DUAE caused micro-fractures and the opening of PPs cells. The extract obtained from DUAE was found to have antioxidant activity comparable to commercial synthetic antioxidants. Results of this preliminary study suggest that DUAE has the potential to transform PPs from agricultural waste to a valuable ingredient. A future systematic research study is proposed to advance the knowledge of the impact of processing parameters in the kinetics of phenolic compounds extraction from potato peels using various extraction methods. Full article
(This article belongs to the Special Issue Phenolic Compounds: Extraction, Optimization, Identification and Applications in Food Industry)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Schematic of the setup of direct ultrasound-assisted extraction (DUAE) method.</p> Full article ">Figure 2
<p>Yields of total phenolic compounds (TPC) from potato peels extracts obtained using the conventional shaking extraction (CSE), direct ultrasound-assisted extraction (DUAE), and indirect ultrasound-assisted extraction (IUAE) methods. Data are means of three measurements, and the error bars indicate standard deviations. Data denoted with the same letter (a, b, c, or d) were not significantly different from the same extraction method at different timings (<span class="html-italic">p</span> &gt; 0.05). Setting for the two ultrasound methods, DUAE and IUAE, were 23 kHz, 25 °C water bath temperature, 600 mVpp, solvent-to-solid ratio 40:1, and particle size smaller than 0.354 mm.</p> Full article ">Figure 3
<p>SEM images of cells in potato peels before extraction (<b>a</b>), after extraction by the CSE method (<b>b</b>), after extraction by the IUAE method (<b>c</b>), and after extraction by the DUAE method (<b>d</b>). All three methods were conducted with a solvent-to-solid ratio of 40:1 in a water bath controlled at 25 °C for 30 min.</p> Full article ">Figure 4
<p>The relationship among the yield of total phenolic compounds (TPC), extraction time (min), and the temperature of potato peels suspension in DUAE. Numbers indicated in the graph denote the temperature of the potato peels suspension. Data are means of three measurements, and error bars indicate standard deviations. Data denoted with the same letter (a, b, c, or d) were not significantly different (<span class="html-italic">p</span> &gt; 0.05). Ultrasound extraction parameters were 23 kHz, 600 mVpp, water bath temperature 25 °C, solvent-to-solid ratio 40:1, and particle size smaller than 0.354 mm.</p> Full article ">Figure 5
<p>The relationship among the yield of total phenolic compounds (TPC), water bath temperature, and mixture temperature in DUAE. Numbers indicated in the graph denote the mixture temperature. Data are means of three measurements, and error bars are standard deviations. Data denoted with the same letter (a, b, c, or d) were not significantly different (<span class="html-italic">p</span> &gt; 0.05). The ultrasound extraction parameters were 23 kHz, 600 mVpp, solvent-to-solid ratio 40:1, 30-min extraction, and particle size smaller than 0.354 mm.</p> Full article ">Figure 6
<p>Relationships among the yield of total phenolic compounds (TPC), extraction amplitude, and mixture temperature in DUAE. Numbers indicated in the graph denote the temperature of the potato peels suspension. Data are means of three measurements, and error bars indicate standard deviations. Data denoted with the same letter (a, b, c, or d) were not significantly different (<span class="html-italic">p</span> &gt; 0.05). Ultrasound extraction parameters were 23 kHz, 600 mVpp, water bath temperature 25 °C, solvent-to-solid ratio 40:1, and particle size smaller than 0.354 mm.</p> Full article ">Figure 7
<p>The relationship among the yield of total phenolic compounds (TPC), solvent-to-solid ratio, and mixture temperature in DUAE. Numbers indicated in the graph denote the temperature of the potato peels suspension. Data are means of three measurements, and error bars indicate standard deviations. Data denoted with the same letter (a, b, c, or d) were not significantly different (<span class="html-italic">p</span> &gt; 0.05). Ultrasound extraction parameters were 23 kHz, 600 mVpp, water bath temperature 25 °C, solvent-to-solid ratio 40:1, and particle size smaller than 0.354 mm.</p> Full article ">Figure 8
<p>The relationship among the yield of total phenolic compounds (TPC), particle size, and mixture temperature during the DUAE extraction. Numbers indicated in the graph denote the temperature of the potato peels suspension. Data are means of three measurements, and error bars indicate standard deviations. Data denoted with the same letter (a, b, c, or d) were not significantly different (<span class="html-italic">p</span> &gt; 0.05). Ultrasound extraction parameters were 23 kHz, 600 mVpp, water bath temperature 25 °C, and solvent-to-solid ratio 40:1. Particle sizes: 20–30 mm (original); &gt;45 mesh (&gt;0.354 mm); 45–100 mesh (0.354–0.150 mm); and &lt;100 mesh (&lt;0.150 mm).</p> Full article ">Figure 9
<p>Scavenging activity of potato peel extract compared with that of tert-butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT). Data are means of three measurements, and error bars indicate standard deviations. Data denoted with the same letter (a, b, c, or d) were not significantly different (<span class="html-italic">p</span> &gt; 0.05). DUAE parameters were 23 kHz, 600 mVpp, water bath temperature 25 °C, solvent-to-solid ratio 40:1, 30-min extraction, and particle size smaller than 0.354 mm.</p> Full article ">
15 pages, 5112 KiB  
Article
Flow Ripple Reduction of Axial-Piston Pump by Structure Optimizing of Outlet Triangular Damping Groove
by Haocen Hong, Chunxiao Zhao, Bin Zhang, Dapeng Bai and Huayong Yang
Processes 2020, 8(12), 1664; https://doi.org/10.3390/pr8121664 - 17 Dec 2020
Cited by 19 | Viewed by 3989
Abstract
The triangular damping groove on the valve plate can effectively reduce the discharge flow ripple of an axial piston pump, which structural parameters will directly affect the pump’s dynamic characteristics. Herein, a multi-parameter data-based structure optimizing method of the triangular damping groove is [...] Read more.
The triangular damping groove on the valve plate can effectively reduce the discharge flow ripple of an axial piston pump, which structural parameters will directly affect the pump’s dynamic characteristics. Herein, a multi-parameter data-based structure optimizing method of the triangular damping groove is investigated using numerical models and simulation results. The mathematical models of a nine-piston pump are proposed and developed by MATLAB/Simulink, and the simulation results are verified by experimental results. Then, the effects of width angle and depth angle on discharge flow are analyzed. Based on the analysis of groove parameters, an optimizing index, which considering the time domain characteristics of discharge flow, is proposed. As results show, comparing with the initial specific groove structure, the amplitude of flow ripple is reduced from 14.6% to 9.8% with the optimized structure. The results demonstrate that the outlet flow ripple can be significantly reduced by the optimized structure, and the proposed multi-parameter optimizing method can play a guiding significance in the design of low-ripple axial piston pumps. Full article
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Figure 1
<p>The configuration of the single piston model.</p> Full article ">Figure 2
<p>Scheme of the simulation model.</p> Full article ">Figure 3
<p>Schematic diagram of the test system.</p> Full article ">Figure 4
<p>Comparison of pressure pulsation (<span class="html-italic">p</span> = 20 MPa, <span class="html-italic">n</span> = 1300 rpm).</p> Full article ">Figure 5
<p>Comparison of discharge flow rate (<span class="html-italic">p</span> = 20 MPa, <span class="html-italic">n</span> = 1300 rpm)</p> Full article ">Figure 6
<p>Simulation variations in the chamber pressure and outlet pressure.</p> Full article ">Figure 7
<p>Simulation variations in the pressure and flow rate.</p> Full article ">Figure 8
<p>Effects on discharge flow rate with different width angles.</p> Full article ">Figure 9
<p>The Figure shows the effects on discharge flow rate with different depth angles: (<b>A</b>) a local enlargement at A in the figure; (<b>B</b>) a local enlargement at B in the figure.</p> Full article ">Figure 10
<p>The Figure shows the variations of flow discordance: (<b>a</b>) flow discordance of varied width angles; (<b>b</b>) flow discordance of varied depth angles.</p> Full article ">Figure 11
<p>The Figure shows the variations of picked time domain features: (<b>a</b>) variations of variance; (<b>b</b>) variations of median absolute deviation; (<b>c</b>) variations of kurtosis; (<b>d</b>) variations of skewness.</p> Full article ">Figure 12
<p>The Figure shows the optimized results of the optimizing index.</p> Full article ">Figure 13
<p>Comparison of initial structure and optimized results.</p> Full article ">
15 pages, 27444 KiB  
Article
Influence of the Gas Bubble Size Distribution on the Ladle Stirring Process
by Mengkun Li and Lintao Zhang
Processes 2020, 8(12), 1663; https://doi.org/10.3390/pr8121663 - 16 Dec 2020
Cited by 8 | Viewed by 2942
Abstract
This work aims at figuring out the influence of gas bubble size distribution on the ladle stirring process. The work is conducted through three-dimensional (3D) numerical simulation based on the finite volume method. Mesh sensitivity test and the cross-validation are performed to ensure [...] Read more.
This work aims at figuring out the influence of gas bubble size distribution on the ladle stirring process. The work is conducted through three-dimensional (3D) numerical simulation based on the finite volume method. Mesh sensitivity test and the cross-validation are performed to ensure the results are mesh independent and the numerical set-up is correct. Two distributions, uniform and Log-normal function, are investigated under different gas flow rates and number of porous plugs. The results indicate that the results, e.g., the axial velocity and the area of the slag eye, have little difference for low flow rate. The difference becomes dominant whilst the flow rate is increasing, such as 600 NL/min. The Log-normal function bubble size distribution gives a larger axial velocity and a smaller slag eye area compared to the uniform bubble size distribution. This work indicated that, at a higher flow rate, the Log-normal function is a better choice to predict the melt behavior and the slag open eye in the ladle refining process if the bubble interaction is not considered. Full article
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Figure 1
<p>Sketch of the ladle (not scaled).</p> Full article ">Figure 2
<p>The adopted boundary conditions (<b>a</b>), the mesh details (<b>b</b>), and the cross-validation (<b>c</b>).</p> Full article ">Figure 3
<p>Overview of the argon bubble injection to the ladle (Case 5): (<b>a</b>) Stage I: bubble injected from plug (<math display="inline"><semantics> <msub> <mi>t</mi> <mi>s</mi> </msub> </semantics></math> = 0.5 s); (<b>b</b>) Stage II: bubbles travel in the bulk melt (<math display="inline"><semantics> <msub> <mi>t</mi> <mi>s</mi> </msub> </semantics></math> = 2.5 s); (<b>c</b>) Stage III: leading bubble reaches the slag layer bottom surface (<math display="inline"><semantics> <msub> <mi>t</mi> <mi>s</mi> </msub> </semantics></math> = 5 s); (<b>d</b>) Stage IV: bubbles travel in the slag layer (<math display="inline"><semantics> <msub> <mi>t</mi> <mi>s</mi> </msub> </semantics></math> = 5.5 s); (<b>e</b>,<b>f</b>) Stage V: leading bubble reaches the slag layer top surface and generates the slag eye (<math display="inline"><semantics> <msub> <mi>t</mi> <mi>s</mi> </msub> </semantics></math> = 6–9 s) and (<b>g</b>,<b>h</b>) Stage VI: the process is stabilized (<math display="inline"><semantics> <msub> <mi>t</mi> <mi>s</mi> </msub> </semantics></math> = 35–45 s).</p> Full article ">Figure 4
<p>The weight ratio of the bubble vs. bubble diameter for Cases 1 to 16. Injected bubble size distribution for both Log-normal function (black curves) and uniform (blue curves). <math display="inline"><semantics> <msubsup> <mi>N</mi> <mrow> <msub> <mi>d</mi> <mi>b</mi> </msub> </mrow> <mrow> <mi>c</mi> <mi>v</mi> </mrow> </msubsup> </semantics></math> and <math display="inline"><semantics> <msubsup> <mi>N</mi> <mi>t</mi> <mrow> <mi>c</mi> <mi>v</mi> </mrow> </msubsup> </semantics></math> denote the number of the bubble for a given diameter (<math display="inline"><semantics> <msub> <mi>d</mi> <mi>b</mi> </msub> </semantics></math>) and the total number of the bubble in a controlled volume.</p> Full article ">Figure 5
<p>Argon bubble distribution for different cases at <math display="inline"><semantics> <msub> <mi>t</mi> <mi>s</mi> </msub> </semantics></math> = 40 s. The legend represents the bubble diameter <math display="inline"><semantics> <msub> <mi>d</mi> <mi>b</mi> </msub> </semantics></math>.</p> Full article ">Figure 6
<p>The slay eye snapshots for Cases 1 to 16 at <math display="inline"><semantics> <msub> <mi>t</mi> <mi>s</mi> </msub> </semantics></math> = 40 s.</p> Full article ">Figure 7
<p>The dimensionless open eye area (<math display="inline"><semantics> <msup> <mi>A</mi> <mo>*</mo> </msup> </semantics></math> %) vs. the dimensionless argon flow rate per plug (<math display="inline"><semantics> <msup> <mi>Q</mi> <mo>*</mo> </msup> </semantics></math>). <math display="inline"><semantics> <msup> <mi>A</mi> <mo>*</mo> </msup> </semantics></math> is defined as the ratio of the open eye area to total area of the slag surface. Black and red represent the cases with uniform and logarithm bubble diameter distribution, respectively.</p> Full article ">Figure 8
<p>(<b>Left</b>): Axial velocity comparison for Cases 4 and 8. The velocity is captured along the line vertical to the ladle bottom and through the center of the porous plug. <span class="html-italic">h</span> is defined as the distance from the measured point to the ladle bottom plane. <span class="html-italic">H</span> is the height of the ladle. The red dashed line (<math display="inline"><semantics> <mrow> <mi>h</mi> <mo>/</mo> <mi>H</mi> </mrow> </semantics></math> = 0.857) represents the slag/steel interface. (<b>Right</b>): turbulent kinetic energy comparison between Case 4 and 8. The data are averaged between 35–45 s.</p> Full article ">Figure 9
<p>The snapshots of the contour of the turbulent kinetic energy for Cases 4 (<math display="inline"><semantics> <mi mathvariant="bold">Left</mi> </semantics></math>) and 8 (<math display="inline"><semantics> <mi mathvariant="bold">Right</mi> </semantics></math>) at <math display="inline"><semantics> <msub> <mi>t</mi> <mi>s</mi> </msub> </semantics></math> = 40 s.</p> Full article ">Figure 10
<p>The snapshots of regions of slag eye with bubbles and the magnitude of plume velocity at <math display="inline"><semantics> <msub> <mi>t</mi> <mi>s</mi> </msub> </semantics></math> = 40 s. (<b>a</b>,<b>c</b>): Case 4; (<b>b</b>,<b>d</b>): Case 8.</p> Full article ">
19 pages, 3007 KiB  
Article
Municipal Solid Waste as Secondary Resource: Selectively Separating Cu(II) from Highly Saline Fly Ash Extracts by Polymer-Assisted Ultrafiltration
by Christine Hettenkofer, Stephan Fromm and Michael Schuster
Processes 2020, 8(12), 1662; https://doi.org/10.3390/pr8121662 - 16 Dec 2020
Cited by 4 | Viewed by 2118
Abstract
Urban mining from fly ash resulting from municipal solid waste incineration (MSWI) is becoming more and more important due to the increasing scarcity of supply-critical metals. Metal extraction from acid fly ash leaching has already been established. In this context selective Cu recovery [...] Read more.
Urban mining from fly ash resulting from municipal solid waste incineration (MSWI) is becoming more and more important due to the increasing scarcity of supply-critical metals. Metal extraction from acid fly ash leaching has already been established. In this context selective Cu recovery is still a challenge. Therefore, our purpose was the separation of Cu(II) from MSWI fly ash extracts by polymer-assisted ultrafiltration (PAUF). We investigated three polyethyleneimines (PEIs) with regard to metal retention, Cu(II) selectivity, Cu(II) loading capacity, and the viscosity of the PEI containing solutions. A demanding challenge was the highly complex matrix of the fly ash extracts, which contain up to 16 interfering metal ions in high concentrations and a chloride content of 60 g L−1. Overcoming that, Cu(II) was selectively enriched and separated from real fly ash extract at pH 3.0. At pH 1.0, a PEI-free Cu(II) concentrate was obtained and PEIs could be regenerated for reuse in further separation cycles. The PAUF conditions developed at laboratory scale were successfully transferred to pilot scale, and hyperbranched PEI (HB-PEI) was found to be the most suitable reagent for PAUF in a technical scale. Moreover, HB-PEI enables photometric control of the Cu(II) enrichment. Full article
(This article belongs to the Special Issue Advanced Technology of Waste Treatment)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Scheme and operating data of tangential flow ultrafiltration pilot scale plant used for Cu(II) enrichment and separation (Andreas Junghans GmbH, Frankenberg/Sachsen, Germany). PP, pressure pump; CF, cross-flow pump.</p> Full article ">Figure 2
<p>Influence of pH on the retention of Cd(II), Cu(II), Ni(II), Pb(II), Zn(II), Fe(III), and Sb(V) using fly ash extracts from KEBAG Zuchwil and MVA Ingolstadt: (<b>a</b>,<b>b</b>) hyperbranched polyethyleneimine (HB-PEI) = 10.0 g L<sup>−1</sup> (Zuchwil), 7.9 g L<sup>−1</sup> (Ingolstadt); (<b>c</b>,<b>d</b>) partially ethoxylated polyethyleneimine (PE-PEI) = 9.4 g L<sup>−1</sup> (Zuchwil), 7.7 g L<sup>−1</sup> (Ingolstadt); (<b>e</b>,<b>f</b>) modified polyethyleneimine (MOD-PEI) = 9.7 g L<sup>−1</sup> (Zuchwil), 8.0 g L<sup>−1</sup> (Ingolstadt).</p> Full article ">Figure 3
<p>Cu(II) loading capacity for HB-PEI (4.6 g L<sup>−1</sup>), PE-PEI (4.7 g L<sup>−1</sup>), and MOD-PEI (3.7 g L<sup>−1</sup>) using fly ash extract (KEBAG Zuchwil).</p> Full article ">Figure 4
<p>Influence of tangential velocity and polymer concentration on (<b>a</b>) permeate flux and (<b>b</b>) specific power consumption (pressure and cross-flow pump) of the pilot plant. HB-PEI diluted in fly ash extract. Transmembrane pressure (TMP) = 5 bar, T = 40 °C.</p> Full article ">Figure 5
<p>Multistep polymer-assisted ultrafiltration (PAUF) process for selective separation of Cu(II) from MSWI fly ash extract. A polymer-free Cu(II) concentrate is obtained in the process.</p> Full article ">Figure 6
<p>Enrichment of Cu(II), Pb(II), Zn(II), and Ca(II) in filtration circuit during continuous Cu(II) retention treating fly ash extracts from MVA Ingolstadt. The process was started with water in the filtration circuit, resulting in an arithmetically negative enrichment. Reference: concentration in the fly ash extract. HB-PEI = 4 g L<sup>−1</sup>, pH 3.0, T = 40 °C.</p> Full article ">Figure 7
<p>Rinsing of filtration circuit with water.</p> Full article ">Figure 8
<p>HB-PEI regeneration by pH decrease and Cu(II) discharge from the filtration circuit by rinsing with water. Cu(II) concentration in cumulative permeate is referenced to initial Cu(II) concentration in the filtration circuit.</p> Full article ">Figure 9
<p>(<b>a</b>) PAUF feed samples of Cu(II) enrichment and final Cu(II) release (far right) from HB-PEI using fly ash extract (KEBAG Zuchwil), HB-PEI = 4.6 g L<sup>−1</sup>. (<b>b</b>) Corresponding UV-vis spectra of increasing Cu(II) loading (gray, black, and green graphs) and release (orange graph). Comparable solutions of [Cu(NH<sub>3</sub>)<sub>4</sub>]<sup>2+</sup> (blue graph) and [Cu(H<sub>2</sub>O)<sub>6</sub>]<sup>2+</sup> (red graph) were additionally analyzed.</p> Full article ">
18 pages, 1167 KiB  
Review
Recent Trends in Pretreatment of Food before Freeze-Drying
by Dariusz Dziki
Processes 2020, 8(12), 1661; https://doi.org/10.3390/pr8121661 - 16 Dec 2020
Cited by 38 | Viewed by 10263
Abstract
Drying is among the most important processes and the most energy-consuming techniques in the food industry. Dried food has many applications and extended shelf life. Unlike the majority of conventional drying methods, lyophilization, also known as freeze-drying (FD), involves freezing the food, usually [...] Read more.
Drying is among the most important processes and the most energy-consuming techniques in the food industry. Dried food has many applications and extended shelf life. Unlike the majority of conventional drying methods, lyophilization, also known as freeze-drying (FD), involves freezing the food, usually under low pressure, and removing water by ice sublimation. Freeze-dried materials are especially recommended for the production of spices, coffee, dried snacks from fruits and vegetables and food for military or space shuttles, as well as for the preparation of food powders and microencapsulation of food ingredients. Although the FD process allows obtaining dried products of the highest quality, it is very energy- and time consuming. Thus, different methods of pretreatment are used for not only accelerating the drying process but also retaining the physical properties and bioactive compounds in the lyophilized food. This article reviews the influence of various pretreatment methods such as size reduction, blanching, osmotic dehydration and application of pulsed electric field, high hydrostatic pressure or ultrasound on the physicochemical properties of freeze-dried food and drying rate. Full article
(This article belongs to the Special Issue Feature Review Papers in Section "Food Processes")
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Figure 1
<p>Relation between Freeze-drying (FD) time and water content in whole bananas and banana puree, (temperature of plates: 60 °C, pressure in the drying chamber: 100 Pa); d.m.—dry mass.</p> Full article ">Figure 2
<p>Measuring stand for the recording of mass changes of sample during FD.</p> Full article ">
14 pages, 5084 KiB  
Article
Switching Monopolar Mode for RF-Assisted Resection and Superficial Ablation of Biological Tissue: Computational Modeling and Ex Vivo Experiments
by Jorge Yaulema, Jose Bon, M. Carmen Gómez-Collado, Juan José Pérez, Enrique Berjano and Macarena Trujillo
Processes 2020, 8(12), 1660; https://doi.org/10.3390/pr8121660 - 16 Dec 2020
Cited by 2 | Viewed by 5040
Abstract
Radiofrequency (RF)-based monopolar (MM) and bipolar mode (BM) applicators are used to thermally create coagulation zones (CZs) in biological tissues with the aim of destroying surface tumors and minimizing blood losses in surgical resection. Both modes have disadvantages as regards safely and in [...] Read more.
Radiofrequency (RF)-based monopolar (MM) and bipolar mode (BM) applicators are used to thermally create coagulation zones (CZs) in biological tissues with the aim of destroying surface tumors and minimizing blood losses in surgical resection. Both modes have disadvantages as regards safely and in obtaining a sufficiently deep coagulation zone (CZ). In this study, we compared both modes versus a switching monopolar mode (SMM) in which the role of the active electrode changes intermittently between the two electrodes of the applicator. In terms of clinical impact, the three modes can easily be selected by the surgeon according to the surgical maneuver. We used computational and experimental models to study the feasibility of working in MM, BM, and SMM and to compare their CZ characteristics. We focused exclusively on BM and SMM, since MM only creates small coagulation zones in the area between the electrodes. The results showed that SMM produces the deepest CZ between both electrodes (33% more than BM) and SMM did not stop the generator when an electrode lost contact with the tissue, as occurred in BM. Our findings suggest that the selective use of SMM and BM with a bipolar applicator offers greater advantages than using each type alone. Full article
(This article belongs to the Special Issue Heat Transfer in Biomedical Applications)
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Figure 1
<p>Scheme of the radiofrequency (RF) application modes: monopolar mode (MM), bipolar mode (BM), and switching monopolar mode (SMM). Arrows indicate the direction of the current flow.</p> Full article ">Figure 2
<p>(<b>A</b>) Bipolar RF applicator used to consider the geometry of the computational model. (<b>B</b>) Scheme of the electrodes’ tips included in the bipolar RF applicator of the left picture (in mm, out of scale).</p> Full article ">Figure 3
<p><b>A</b>: Geometry and materials used in the study. <b>B</b>: Scheme of the intermediate space between the two applicator tips where the coagulation zone (CZ) (curve <math display="inline"><semantics> <mi mathvariant="sans-serif">Ω</mi> </semantics></math> = 1) was expected. CZ depth was measured on the middle plane between the tips. CZ diameter was the longest distance between two points on a parallel plane to the upper tissue surface. Figures out of scale.</p> Full article ">Figure 4
<p>Three different angles of penetration considered for the geometry of the models used in the third set of simulations with rotation angles of 10°, 20°, and 30° with respect to the initial geometry.</p> Full article ">Figure 5
<p>Temperature distribution (°C) and isosurface <math display="inline"><semantics> <mi mathvariant="sans-serif">Ω</mi> </semantics></math> = 1 (black line) for the BM in the symmetry plane of the geometry representing cases of <span class="html-italic">V<sub>0</sub></span> = 30 (t = 16 s), 35 (t = 16 s), 40 (t = 8.6 s), 45 (t = 4.9 s), and 50 V (t = 3.2 s), as selected in <a href="#processes-08-01660-t002" class="html-table">Table 2</a>. The times in each graph are the times that satisfied the stop criterion.</p> Full article ">Figure 6
<p>Temperature distribution (°C) and isosurface <math display="inline"><semantics> <mi mathvariant="sans-serif">Ω</mi> </semantics></math> = 1 (black line) for SMM in the symmetry plane of the geometry representing cases of <span class="html-italic">V<sub>0</sub></span> = 40 (t = 16 s), 45 (t = 14 s), 50 (t = 8.88 s), 55 (t = 5.77 s), and 60 V (t = 4 s), as selected in <a href="#processes-08-01660-t002" class="html-table">Table 2</a>. The times in each graph are the times that satisfied the stop criterion.</p> Full article ">Figure 7
<p>Temperature distribution (°C) and isosurface <math display="inline"><semantics> <mi mathvariant="sans-serif">Ω</mi> </semantics></math> = 1 (black line) for the MM in the symmetry plane of the geometry representing cases of <span class="html-italic">V<sub>0</sub></span> = 50 (t = 16 s), 55 (t = 15.4 s), 60 (t = 9.7 s), 65 (t = 6.5 s), and 70 V (t = 4.6 s). The times in each graph are the times that satisfied the stop criterion.</p> Full article ">Figure 8
<p>Temperature distribution (°C) and isosurface <math display="inline"><semantics> <mi mathvariant="sans-serif">Ω</mi> </semantics></math> = 1 (black line) for the SMM (45 V) in the symmetry plane of the geometry representing cases of <span class="html-italic">f<sub>S</sub></span> = 4, 2, 1, 1/2, 1/4, and 1/8. The times in each graph are the times that satisfied the stop criterion.</p> Full article ">Figure 9
<p>Temperature distribution (°C) and isosurface Ω = 1 (black line) for the BM and SMM modes in the symmetry plane of the geometry using different RF applicator angles of penetration (0, 10, 20 and 30°). Voltage values of 40 and 45 V were used for BM and SMM, respectively. <span class="html-italic">f<sub>S</sub></span> = 4 was used in SMM. The time is the <span class="html-italic">t<sub>end</sub></span> value in each simulation.</p> Full article ">Figure 10
<p>(<b>A</b>–<b>C</b>) show the spatial CZ distribution in the cross-sectional plane in BM (40 V, 120 s), MM (60 V, 30 s), and SMM (45 V, 120 s, <span class="html-italic">f<sub>S</sub></span> = 4), respectively. (<b>D,E</b>) show the CZ (surface view) for MM (60 V, 30 s) and SMM (45 V, 12 s, <span class="html-italic">f<sub>S</sub></span> = 1/8), respectively. (<b>F</b>) is the cross-sectioned CZ shown in (<b>E</b>).</p> Full article ">
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