Processes

17 pages, 3651 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Cladium mariscus Saw-Sedge versus Sawdust—Efficient Biosorbents for Removal of Hazardous Textile Dye C.I. Basic Blue 3 from Aqueous Solutions

by Przemysław Bartczak, Monika Wawrzkiewicz, Sławomir Borysiak and Teofil Jesionowski

Processes 2022, 10(3), 586; https://doi.org/10.3390/pr10030586 - 17 Mar 2022

Cited by 8 | Viewed by 2069

Abstract

Bio-based waste materials are more often used as effective and cheap adsorbents to remove toxic organic compounds such dyes. Batch adsorption of C.I. Basic Blue 3 (BB3) onto Cladium mariscus saw-sedge was studied in comparison with sawdust obtained from various species of wood [...] Read more.

Bio-based waste materials are more often used as effective and cheap adsorbents to remove toxic organic compounds such dyes. Batch adsorption of C.I. Basic Blue 3 (BB3) onto Cladium mariscus saw-sedge was studied in comparison with sawdust obtained from various species of wood in order to explore their potential application as low-cost sorbents for basic dye removal from wastewaters. The effect of phase contact time (1–240 min), initial dye concentration (50–200 mg/L), and the auxiliaries presence (10–60 g/L NaCl and 0.1–0.75 g/L anionic surfactant) on BB3 uptake was investigated. The adsorption kinetic data followed the pseudo-second order equation rather than pseudo-first order one. The equilibrium adsorption data were analyzed using the Langmuir, Freundlich, and Tempkin isotherm models. The monolayer sorption capacities decreased from 44.29 to 42.07 mg/g for Cladium mariscus saw-sedge and from 28.69 to 27.5 mg/g for sawdust with temperature increasing from 20 to 50 °C. The thermodynamic parameters such as the change in free energy (∆G°), enthalpy (∆H°), and entropy (∆S°) were calculated, too. Full article

(This article belongs to the Section Environmental and Green Processes)

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18 pages, 5821 KiB

Open AccessEditor’s ChoiceArticle

Influence of Materials Parameters of the Coil Sheet on the Formation of Defects during the Manufacture of Deep-Drawn Cups

by Wojciech Baran, Krzysztof Regulski and Andrij Milenin

Processes 2022, 10(3), 578; https://doi.org/10.3390/pr10030578 - 16 Mar 2022

Cited by 2 | Viewed by 2956

Abstract

During the process of deep drawing of cylindrical thin-walled products from aluminum sheets, the occurrence of product defects in the form of breaking the material continuity is observed. This has a very large impact on the efficiency of production lines and the number [...] Read more.

During the process of deep drawing of cylindrical thin-walled products from aluminum sheets, the occurrence of product defects in the form of breaking the material continuity is observed. This has a very large impact on the efficiency of production lines and the number of generated scraps. The number of defects depends on many factors, including the material and the process properties. Because the problem appears after changing one material to another, while the process parameters do not change, it was assumed that the material has the main influence on the number of defects. To reduce the number of defects, a tool is needed to predict threats to the process. Decision tree models were used for this purpose. Using the tree interaction algorithms, the influence of the chemical composition and strength parameters of the 3xxx series aluminum alloy on the number of generated defects was investigated. Increased Silicon (Si) and Iron (Fe) values generated a higher number of defects. Increased yield strength (YS) and decreased elongation (E) also generated a higher number of defects. Based on the results, a defect prediction tool was created, where after entering the parameters of the material, it is possible to predict production hazards. Full article

(This article belongs to the Topic Processing, Analysis, Modelling and Mechanics of Materials and Structures)

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15 pages, 1405 KiB

Open AccessEditor’s ChoiceArticle

Phytosterol, Tocopherol and Carotenoid Retention during Commercial Processing of Brassica napus (Canola) Oil

by Clare L. Flakelar, Randy Adjonu, Gregory Doran, Julia A. Howitt, David J. Luckett and Paul D. Prenzler

Processes 2022, 10(3), 580; https://doi.org/10.3390/pr10030580 - 16 Mar 2022

Cited by 17 | Viewed by 4046

Abstract

Brassica napus (canola) seed is a rich source of phytosterols, tocopherols and carotenoids, which all have recognized health benefits, although these are reduced or lost during crude oil refinement. Many studies are now outdated, so new research to monitor bioactive retention through current [...] Read more.

Brassica napus (canola) seed is a rich source of phytosterols, tocopherols and carotenoids, which all have recognized health benefits, although these are reduced or lost during crude oil refinement. Many studies are now outdated, so new research to monitor bioactive retention through current processing techniques is warranted. In this work, canola seed, in-process seed, and oil samples were collected from the major stages of five commercial canola oil processes. Analysis of phytosterols, tocopherols and carotenoids indicated seed pre-treatment enhanced bioactive concentrations in the crude oil. Although the bleaching step in each process eliminated all carotenoids, high concentrations of phytosterols and tocopherols remained in the refined oil across all processes, with losses notably lower than those found in previous reports. Moreover, crude oil samples from a two-stage cold pressing process showed greatly enriched concentrations of tocopherols (+122%), sterols (+140%) and carotenoids (+217%). The results show that modern Australian canola oil processing retains high phytosterol and tocopherol concentrations and warrants further investigation into bioactive enrichment strategies. Given the growing interest in health-enhanced foods, this study provides opportunities for nutrition and health-enhanced oil products and the potential for adding value in the edible oil industry. Full article

(This article belongs to the Special Issue Food Processing Technologies Applied to Cereals, Legumes, Oilseeds, Alternative Food Raw Materials and Their Derivatives)

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16 pages, 1526 KiB

Open AccessEditor’s ChoiceArticle

Fast Electrochemical Measurement of Laccase Activity for Monitoring Grapes’ Infection with Botrytis cinerea

by Andreea Catalina Lulea, Robert Ruginescu, Roberta Maria Banciu, Catalina Pantazi, Elena Brinduse, Marian Ion, Silvia Quintela, Edurne Elejalde, Laura Fernández-de-Castro, Maria Carmen Villarán, Zuria Ruiz-de-Vergara, Cristobal Ruíz, Petru Epure, Cristina Purcarea and Alina Vasilescu

Processes 2022, 10(3), 575; https://doi.org/10.3390/pr10030575 - 15 Mar 2022

Cited by 4 | Viewed by 3493

Abstract

Grapes’ infection with the fungi Botrytis cinerea is one of the major causes of economic loss in the winemaking sector worldwide. The laccase activity of grapes is considered an appropriate indicator of this type of fungal infection, and enzymatic activity higher than 3 [...] Read more.

Grapes’ infection with the fungi Botrytis cinerea is one of the major causes of economic loss in the winemaking sector worldwide. The laccase activity of grapes is considered an appropriate indicator of this type of fungal infection, and enzymatic activity higher than 3 U/mL indicates a high risk of irreversibly damaged grape must due to enzymatic browning. This work describes a fast test for the measurement of laccase activity based on a dual optical and electrochemical detection method. A paper sensor impregnated with the enzymatic substrate dye 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) provides a semi-quantitative optical measurement. While the paper sensor can be used independently, when combined with a screen-printed electrode and amperometry measurements, it enables the quantitative detection of laccase activities down to 0.4 U/mL in only 5 min. The method was applied for monitoring the artificial infection of white, rosé, and red grapes with different strains of Botrytis cinerea. The results were confirmed by parallel analysis using the spectrophotometric method of laccase activity determination based on syringaldazine. The influence of the fungal strain and type of grape on laccase activity levels is reported. The demonstrated robustness, simplicity, and versatility of the developed method make it ideal for application on-site in the vineyard or at grape processing points. Full article

(This article belongs to the Special Issue Recent Research on Electrochemical Bioassays)

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18 pages, 4283 KiB

Open AccessEditor’s ChoiceArticle

Analysis and Implementation of a Bidirectional Converter with Soft Switching Operation

by Bor-Ren Lin

Processes 2022, 10(3), 561; https://doi.org/10.3390/pr10030561 - 13 Mar 2022

Cited by 4 | Viewed by 2507

Abstract

This paper presents a soft switching direct current (DC) converter, with the benefits of bidirectional power conversion and wide-ranging voltage operation for battery charging and discharging capability. A series resonant circuit with variable switching frequency modulation is used to achieve the advantages of [...] Read more.

This paper presents a soft switching direct current (DC) converter, with the benefits of bidirectional power conversion and wide-ranging voltage operation for battery charging and discharging capability. A series resonant circuit with variable switching frequency modulation is used to achieve the advantages of soft switching turn-on or turn-off of semiconductor devices. Therefore, the switching power losses in power devices can be reduced. A symmetric resonant circuit topology with a capacitor–inductor–inductor–capacitor (CLLC) structure is adopted to achieve a bidirectional power conversion capability for battery storage units in electric vehicle applications. Due to the symmetric circuit structure on both input and output sides, the converter has similar voltage gains for each power flow operation. In order to overcome the drawback of narrow voltage range operation in conventional resonant converters, a variable transformer turns ratio is adopted in the circuit, to achieve wide output voltage operation (150–450 V) for battery charging applications. To demonstrate the converter performance, a 1-kW laboratory prototype was constructed and tested. Experimental results are provided, to verify the effectiveness of the studied circuit. Full article

(This article belongs to the Special Issue Power Electronic for Photovoltaic Systems)

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14 pages, 2784 KiB

Open AccessEditor’s ChoiceArticle

Comparison of Knudsen Diffusion and the Dusty Gas Approach for the Modeling of the Freeze-Drying Process of Bulk Food Products

by Patrick Levin, Moritz Buchholz, Vincent Meunier, Ulrich Kessler, Stefan Palzer and Stefan Heinrich

Processes 2022, 10(3), 548; https://doi.org/10.3390/pr10030548 - 11 Mar 2022

Cited by 5 | Viewed by 3062

Abstract

Freeze-drying is generally used to achieve high quality products and preserve thermal sensitive components; however, it is also considered as a high energy and costly process. Modeling of the process can help to optimize the process to reduce these drawbacks. In this work, [...] Read more.

Freeze-drying is generally used to achieve high quality products and preserve thermal sensitive components; however, it is also considered as a high energy and costly process. Modeling of the process can help to optimize the process to reduce these drawbacks. In this work, a mathematical model is presented to predict the heat and mass transfer behavior for freeze-drying of porous frozen food particles during freeze-drying to optimize the process. For the mass transfer, a comparison between Knudsen diffusion and the more complex dusty-gas approach is performed. Simulation results of a single particle are validated by experiments of single-layer drying to extend the usage of this model from a single particle to a particle bed. For the moisture transfer, adaption parameters are introduced and evaluated. A comparison shows a good agreement of the model with experimental results. The results furthermore suggest a strong correlation of the drying kinetics with pore size and particle porosity. An increase in the pore diameter strongly improves the overall mass transfer rates and hence is a suitable parameter for an effective increase of the drying rates in freeze-drying. Full article

(This article belongs to the Special Issue Advanced in Dewatering and Drying Processes)

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18 pages, 12124 KiB

Open AccessEditor’s ChoiceArticle

Optimization of a Tricalcium Phosphate-Based Bone Model Using Cell-Sheet Technology to Simulate Bone Disorders

by Alexandra Damerau, Frank Buttgereit and Timo Gaber

Processes 2022, 10(3), 550; https://doi.org/10.3390/pr10030550 - 11 Mar 2022

Cited by 3 | Viewed by 2622

Abstract

Bone diseases such as osteoporosis, delayed or impaired bone healing, and osteoarthritis still represent a social, financial, and personal burden for affected patients and society. Fully humanized in vitro 3D models of cancellous bone tissue are needed to develop new treatment strategies and [...] Read more.

Bone diseases such as osteoporosis, delayed or impaired bone healing, and osteoarthritis still represent a social, financial, and personal burden for affected patients and society. Fully humanized in vitro 3D models of cancellous bone tissue are needed to develop new treatment strategies and meet patient-specific needs. Here, we demonstrate a successful cell-sheet-based process for optimized mesenchymal stromal cell (MSC) seeding on a β-tricalcium phosphate (TCP) scaffold to generate 3D models of cancellous bone tissue. Therefore, we seeded MSCs onto the β-TCP scaffold, induced osteogenic differentiation, and wrapped a single osteogenically induced MSC sheet around the pre-seeded scaffold. Comparing the wrapped with an unwrapped scaffold, we did not detect any differences in cell viability and structural integrity but a higher cell seeding rate with osteoid-like granular structures, an indicator of enhanced calcification. Finally, gene expression analysis showed a reduction in chondrogenic and adipogenic markers, but an increase in osteogenic markers in MSCs seeded on wrapped scaffolds. We conclude from these data that additional wrapping of pre-seeded scaffolds will provide a local niche that enhances osteogenic differentiation while repressing chondrogenic and adipogenic differentiation. This approach will eventually lead to optimized preclinical in vitro 3D models of cancellous bone tissue to develop new treatment strategies. Full article

(This article belongs to the Special Issue Bioactive Composites for Bone Substitution)

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15 pages, 9236 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Non-Thermal Atmospheric Plasma for Microbial Decontamination and Removal of Hazardous Chemicals: An Overview in the Circular Economy Context with Data for Test Applications of Microwave Plasma Torch

by Yovana Todorova, Evgenia Benova, Plamena Marinova, Ivaylo Yotinov, Todor Bogdanov and Yana Topalova

Processes 2022, 10(3), 554; https://doi.org/10.3390/pr10030554 - 11 Mar 2022

Cited by 17 | Viewed by 4068

Abstract

The transformation of our linear “take-make-waste” system to a cyclic flow of materials and energy is a priority task for society, but the circular use of waste streams from one industry/sector as a material input for another must be completely safe. The need [...] Read more.

The transformation of our linear “take-make-waste” system to a cyclic flow of materials and energy is a priority task for society, but the circular use of waste streams from one industry/sector as a material input for another must be completely safe. The need for new advanced technologies and methods ensuring both microbiological safety and the removal of potential chemical residues in used materials and products is urgent. Non-thermal atmospheric plasma (cold atmospheric plasma—CAP) has recently attracted great research interest as an alternative for operative solutions of problems related to safety and quality control. CAP is a powerful tool for the inactivation of different hazardous microorganisms and viruses, and the effective decontamination of surfaces and liquids has been demonstrated. Additionally, the plasma’s active components are strong oxidizers and their synergetic effect can lead to the degradation of toxic chemical compounds such as phenols and azo-dyes. Full article

(This article belongs to the Special Issue Sustainable Shift to Circular Solutions for Water and Waste Management)

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30 pages, 1064 KiB

Open AccessEditor’s ChoiceArticle

The Product Customization Process in Relation to Industry 4.0 and Digitalization

by Martin Pech and Jaroslav Vrchota

Processes 2022, 10(3), 539; https://doi.org/10.3390/pr10030539 - 9 Mar 2022

Cited by 41 | Viewed by 18722

Abstract

Today’s customer no longer wants one-size-fits-all products but expects products and services to be as tailored as possible. Mass customization and personalization are becoming a trend in the digitalization strategy of enterprises and manufacturing in Industry 4.0. The purpose of the paper is [...] Read more.

Today’s customer no longer wants one-size-fits-all products but expects products and services to be as tailored as possible. Mass customization and personalization are becoming a trend in the digitalization strategy of enterprises and manufacturing in Industry 4.0. The purpose of the paper is to develop and validate a conceptual model for leveraging Industry 4.0 and digitalization to support product customization. We explored the implications and impacts of Industry 4.0 and digitalization on product customization processes and determine the importance of variables. We applied structural equation modeling (SEM) to test our hypotheses regarding the antecedents and consequences of digitalization and Industry 4.0. We estimated the process model using the partial least squares (PLS) method, and goodness of fit measures show acceptable values. The proposed model considers relationships between technology readiness, digitalization, internal and external integration, internal value chain, and customization. The results show the importance of digitalization and technology readiness for product customization. The results reveal that the variable of internal integration plays a crucial mediating role in applying new technologies and digitalization for customization. The paper’s main contribution is the conclusion that, for successful implementation of the customization process, models are required to focus on the internal and external factors of the business environment. Our findings are supported by various practical applications of possible product customization. Full article

(This article belongs to the Special Issue Manufacturing Industry 4.0: Trends and Perspectives)

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19 pages, 419 KiB

Open AccessEditor’s ChoiceArticle

Predicting the Solubility of Nonelectrolyte Solids Using a Combination of Molecular Simulation with the Solubility Parameter Method MOSCED: Application to the Wastewater Contaminants Monuron, Diuron, Atrazine and Atenolol

by Rachel C. Ollier, Thomas Nguyen, Hrithik Agarwal, Jeremy R. Phifer, Larissa Ferreira da Silva, Gabriel Gonçalves Nogueira, Ana Karolyne Pereira Barbosa, Ryan T. Ley, Elizabeth J. O’Loughlin, Brett T. Rygelski, Spencer J. Sabatino and Andrew S. Paluch

Processes 2022, 10(3), 538; https://doi.org/10.3390/pr10030538 - 9 Mar 2022

Cited by 2 | Viewed by 2865

Abstract

Methods to predict the equilibrium solubility of nonelectrolyte solids are indispensable for early-stage process development, design, and feasibility studies. Conventional analytic methods typically require reference data to regress parameters, which may not be available or limited for novel systems. Molecular simulation is a [...] Read more.

Methods to predict the equilibrium solubility of nonelectrolyte solids are indispensable for early-stage process development, design, and feasibility studies. Conventional analytic methods typically require reference data to regress parameters, which may not be available or limited for novel systems. Molecular simulation is a promising alternative, but is computationally intensive. Here, we demonstrate the ability to use a small number of molecular simulation free energy calculations to generate reference data to regress model parameters for the analytical MOSCED (modified separation of cohesive energy density) model. The result is an efficient analytical method to predict the equilibrium solubility of nonelectrolyte solids. The method is demonstrated for the wastewater contaminants monuron, diuron, atrazine and atenolol. Predictions for monuron, diuron and atrazine are in reasonable agreement with MOSCED parameters regressed using experimental solubility data. Predictions for atenolol are inferior, suggesting a potential limitation in the adopted molecular models, or the solvents selected to generate the necessary reference data. Full article

(This article belongs to the Special Issue Thermodynamics: Modeling and Simulation)

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15 pages, 4994 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Continuous Conical-Mill Operation for Dry Coating of Pharmaceutical Powders: The Role of Processing Time

by William Roy, Inès Esma Achouri, Sophie Hudon, Jean-Sébastien Simard and Nicolas Abatzoglou

Processes 2022, 10(3), 540; https://doi.org/10.3390/pr10030540 - 9 Mar 2022

Cited by 3 | Viewed by 2593

Abstract

Over the last decade, the conical mill has emerged as a potential piece of equipment to use for continuous dry coating pharmaceutical powders. In this work, silicon dioxide was used as a guest particle on two excipients, fast flow lactose (FFL) and grade [...] Read more.

Over the last decade, the conical mill has emerged as a potential piece of equipment to use for continuous dry coating pharmaceutical powders. In this work, silicon dioxide was used as a guest particle on two excipients, fast flow lactose (FFL) and grade PH200 microcrystalline cellulose (MCC), for dry coating by a conical mill with a modified screen that permitted batch and continuous mode operation. Samples were pre-processed in a V-blender. SEM images, particle size distribution, and EDS mapping were used to characterise the treated powders. Pre-processed samples showed some discrete coating of the host particle. After batch processing, the samples were covered with a complete coating. When processed at high impeller speed, coating of FFL was a mix of A200P and FFL fines generated by attrition. Continuous mode processed samples, which had a lower processing time, were coated discretely and showed a better coating than the pre-processed samples. Increasing guest/host mass ratio with FFL host particle had a positive impact on the quality of the coating. These results help to build the case that the processing time of the conical mill is a key parameter to the success of the conical mill as dry coating equipment in the pharmaceutical industry. Full article

(This article belongs to the Special Issue Particulate Processes in the Formulation of Pharmaceuticals, Nutraceuticals and Bioactive Compounds)

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12 pages, 1078 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Insights into the Impact of Rosmarinic Acid on CHO Cell Culture Improvement through Transcriptomics Analysis

by Zhuangrong Huang, Jianlin Xu, Jun Tian, Kathryn L. Aron, Yueming Qian, Michael C. Borys, Zhengjian Li and Girish Pendse

Processes 2022, 10(3), 533; https://doi.org/10.3390/pr10030533 - 8 Mar 2022

Cited by 1 | Viewed by 3673

Abstract

The use of antioxidants in Chinese hamster ovary (CHO) cell cultures to improve monoclonal antibody production has been a topic of great interest. Nevertheless, the antioxidants do not have consistent benefits of production improvement, which might be cell line specific and/or process specific. [...] Read more.

The use of antioxidants in Chinese hamster ovary (CHO) cell cultures to improve monoclonal antibody production has been a topic of great interest. Nevertheless, the antioxidants do not have consistent benefits of production improvement, which might be cell line specific and/or process specific. In this work, we investigated how treatment with the antioxidant rosmarinic acid (RA) improved cell growth and titer in CHO cell cultures using transcriptomics. In particular, transcriptomics analysis indicated that RA treatment modified gene expression and strongly affected the MAPK and PI3K/Akt signaling pathways, which regulate cell survival and cell death. Moreover, it was observed that these signaling pathways, which had been identified to be up-regulated on day 2 and day 6 by RA, were also up-regulated over time (from initial growth phase day 2 to slow growth or protein production phase day 6) in both conditions. In summary, this transcriptomics analysis provides insights into the role of the antioxidant RA in industrial cell culture processes. The current study also represents an example in the industry of how omics can be applied to gain an in-depth understanding of CHO cell biology and to identify critical pathways that can contribute to cell culture process improvement and cell line engineering. Full article

(This article belongs to the Section Biological Processes and Systems)

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49 pages, 8161 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Modeling and Optimization of Heavy Metals Biosorption by Low-Cost Sorbents Using Response Surface Methodology

by Daniela Ionela Fertu, Laura Bulgariu and Maria Gavrilescu

Processes 2022, 10(3), 523; https://doi.org/10.3390/pr10030523 - 6 Mar 2022

Cited by 21 | Viewed by 3981

Abstract

This paper exploits, through modeling and optimization, the experimental laboratory data on the biosorption of heavy metal ions Pb(II), Cd(II), and Zn(II) from aqueous media using soybean and soybean waste biomasses. The biosorption modeling was performed using the Response Surface Methodology, followed by [...] Read more.

This paper exploits, through modeling and optimization, the experimental laboratory data on the biosorption of heavy metal ions Pb(II), Cd(II), and Zn(II) from aqueous media using soybean and soybean waste biomasses. The biosorption modeling was performed using the Response Surface Methodology, followed by optimization based on numerical methods. The aim of the modeling was to establish the most probable mathematical relationship between the dependent variables (the biosorption efficiency of the biosorbents when adsorbing metal ions, R(%), and the biosorption capacity of sorbents, q(mg/g)) and the process parameters (pH; sorbent dose, DS (g/L); initial metal ion concentration in solution, c₀ (mg/L); contact time, t_c (min); temperature, T (°C)), validated by methodologies specific to the multiple regression analysis. Afterward, sets of solutions were obtained through optimization that correlate various values of the process parameters to maximize the objective function. These solutions also confirmed the performance of soybean waste biomass in the removal of heavy metal ions from polluted aqueous effluents. The results were validated experimentally. Full article

(This article belongs to the Special Issue Innovative Materials and Processes for Removal of Biopersistent Pollutants)

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20 pages, 2671 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Proof-of-Concept of Continuous Transfection for Adeno-Associated Virus Production in Microcarrier-Based Culture

by Brian Ladd, Kevin Bowes, Mats Lundgren, Torbjörn Gräslund and Veronique Chotteau

Processes 2022, 10(3), 515; https://doi.org/10.3390/pr10030515 - 4 Mar 2022

Cited by 6 | Viewed by 5716

Abstract

Adeno-associated virus vectors (AAV) are reported to have a great potential for gene therapy, however, a major bottleneck for this kind of therapy is the limitation of production capacity. Higher specific AAV vector yield is often reported for adherent cell systems compared to [...] Read more.

Adeno-associated virus vectors (AAV) are reported to have a great potential for gene therapy, however, a major bottleneck for this kind of therapy is the limitation of production capacity. Higher specific AAV vector yield is often reported for adherent cell systems compared to cells in suspension, and a microcarrier-based culture is well established for the culture of anchored cells on a larger scale. The purpose of the present study was to explore how microcarrier cultures could provide a solution for the production of AAV vectors based on the triple plasmid transfection of HEK293T cells in a stirred tank bioreactor. In the present study, cells were grown and expanded in suspension, offering the ease of this type of operation, and were then anchored on microcarriers in order to proceed with transfection of the plasmids for transient AAV vector production. This process was developed in view of a bioreactor application in a 200 mL stirred-tank vessel where shear stress aspects were studied. Furthermore, amenability to a continuous process was studied. The present investigation provided a proof-of-concept of a continuous process based on microcarriers in a stirred-tank bioreactor. Full article

(This article belongs to the Special Issue Bioprocess Systems Engineering Applications in Pharmaceutical Manufacturing)

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12 pages, 1738 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Decrease in Ca²⁺ Concentration in Quail Cardiomyocytes Is Faster than That in Rat Cardiomyocytes

by Yuhei Ogura, Hiroaki Ito, Shukei Sugita, Masanori Nakamura and Yoshihiro Ujihara

Processes 2022, 10(3), 508; https://doi.org/10.3390/pr10030508 - 3 Mar 2022

Cited by 3 | Viewed by 2404

Abstract

Mammals and birds have quicker heart rates compared to other species. Mammalian cardiomyocytes have T-tubule membranes that facilitate rapid changes in Ca²⁺ concentrations. In contrast, bird cardiomyocytes do not possess T-tubule membranes, which raises the question of how birds achieve fast heartbeats. [...] Read more.

Mammals and birds have quicker heart rates compared to other species. Mammalian cardiomyocytes have T-tubule membranes that facilitate rapid changes in Ca²⁺ concentrations. In contrast, bird cardiomyocytes do not possess T-tubule membranes, which raises the question of how birds achieve fast heartbeats. In this study, we compared the changes in Ca²⁺ concentration in cardiomyocytes isolated from adult quails and rats to elucidate the mechanism resulting in rapid heart rates in birds. Cardiomyocytes isolated from quails were significantly narrower than those isolated from rats. When Ca²⁺ concentration changes in the entire cardiomyocytes were measured using Fura-2 acetoxymethyl ester (AM), the time to peak was statistically longer in quails than in rats. In contrast, the decay time was markedly shorter in quails than in rats. As a result, the total time of Ca²⁺ concentration change was shorter in quails than in rats. A spatiotemporal analysis of Ca²⁺ concentration changes in quail cardiomyocytes showed that the decrease in Ca²⁺ concentration was faster in the center of the cell than near the cell membrane. These results suggest that avian cardiomyocytes achieve rapid changes in Ca²⁺ concentration by increasing the Ca²⁺ removal capacity in the central part of the cell compared to mammalian cardiomyocytes. Full article

(This article belongs to the Section Manufacturing Processes and Systems)

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19 pages, 2305 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Modulation of Volatile Thiol Release during Fermentation of Red Musts by Wine Yeast

by Antonio G. Cordente, Christopher D. Curtin, Mark Solomon, Allie C. Kulcsar, Flynn Watson, Lisa Pisaniello, Simon A. Schmidt and Damian Espinase Nandorfy

Processes 2022, 10(3), 502; https://doi.org/10.3390/pr10030502 - 2 Mar 2022

Cited by 8 | Viewed by 4189

Abstract

During the alcoholic fermentation of grape sugars, wine yeast produces a range of secondary metabolites that play a critical role in the aroma profile of wines. One of the most impactful yeast-modified compound families, particularly in white wines, are the ‘fruity’ polyfunctional thiols, [...] Read more.

During the alcoholic fermentation of grape sugars, wine yeast produces a range of secondary metabolites that play a critical role in the aroma profile of wines. One of the most impactful yeast-modified compound families, particularly in white wines, are the ‘fruity’ polyfunctional thiols, which include 3-mercaptohexan-1-ol (3-MH) and 4-mercapto-4-methylpentan-2-one (4-MMP). While the formation and stylistic contribution of these thiols have been extensively researched in white wines, little is known about the conditions leading to their formation in red wines. In this study, we explored the ability of yeast strains to modulate the release of these aroma compounds during the fermentation of two red musts. In laboratory-scale Pinot Noir fermentations, the formation of 3-MH strongly correlated with yeast β-lyase activity, particularly with the presence of certain genotypes of the flavour-releasing gene IRC7. Subsequent production of Grenache wine at the pilot scale, with detailed compositional and sensory analysis, was undertaken to confirm laboratory-scale observations. A commercial wine strain used for expressing ‘fruity’ thiols in Sauvignon Blanc was shown to produce wines that exhibited more intense red fruit aromas. These results reveal an opportunity for winemakers to shape red wine aroma and flavour by using yeasts that might typically be considered for white wine production. Full article

(This article belongs to the Special Issue Role of Yeast in Wine Fermentation Processes)

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31 pages, 1195 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Enzyme Immobilization and Co-Immobilization: Main Framework, Advances and Some Applications

by Joaquim Bié, Bruno Sepodes, Pedro C. B. Fernandes and Maria H. L. Ribeiro

Processes 2022, 10(3), 494; https://doi.org/10.3390/pr10030494 - 1 Mar 2022

Cited by 102 | Viewed by 17664

Abstract

Enzymes are outstanding (bio)catalysts, not solely on account of their ability to increase reaction rates by up to several orders of magnitude but also for the high degree of substrate specificity, regiospecificity and stereospecificity. The use and development of enzymes as robust biocatalysts [...] Read more.

Enzymes are outstanding (bio)catalysts, not solely on account of their ability to increase reaction rates by up to several orders of magnitude but also for the high degree of substrate specificity, regiospecificity and stereospecificity. The use and development of enzymes as robust biocatalysts is one of the main challenges in biotechnology. However, despite the high specificities and turnover of enzymes, there are also drawbacks. At the industrial level, these drawbacks are typically overcome by resorting to immobilized enzymes to enhance stability. Immobilization of biocatalysts allows their reuse, increases stability, facilitates process control, eases product recovery, and enhances product yield and quality. This is especially important for expensive enzymes, for those obtained in low fermentation yield and with relatively low activity. This review provides an integrated perspective on (multi)enzyme immobilization that abridges a critical evaluation of immobilization methods and carriers, biocatalyst metrics, impact of key carrier features on biocatalyst performance, trends towards miniaturization and detailed illustrative examples that are representative of biocatalytic applications promoting sustainability. Full article

(This article belongs to the Special Issue Bioprocess Engineering: Sustainable Manufacturing for a Green Society)

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11 pages, 2236 KiB

Open AccessEditor’s ChoiceArticle

Potential Use of Microbial Fuel Cell Technology in Wastewater Treatment

by Ralitza Koleva, Gergana Peeva, Hyuseyin Yemendzhiev and Valentin Nenov

Processes 2022, 10(3), 486; https://doi.org/10.3390/pr10030486 - 28 Feb 2022

Cited by 5 | Viewed by 3372

Abstract

Two options, in regard to applying microbial fuel cells (MFCs) in water treatment, are under discussion, namely the conversion of the chemical energy of organic substrates to electricity, as well as the use their potential to reduce different species, such as the ionic [...] Read more.

Two options, in regard to applying microbial fuel cells (MFCs) in water treatment, are under discussion, namely the conversion of the chemical energy of organic substrates to electricity, as well as the use their potential to reduce different species, such as the ionic form of copper (Cu²⁺ converted to metal copper) and iron (Fe³⁺ converted to Fe²⁺). The high reduction potential of Cu²⁺ and Fe³⁺ makes the processes of electricity production and metal reduction, to be performed simultaneously in MFC, achievable. The electrical yield measurement during the experiments of anodic organic matter degradation by MFC in treating an artificial wastewater with chemical oxygen demand (COD) 0.6 and 1.6 g O₂·dm⁻³, as initial COD, are given. It is demonstrated that the higher organic load is associated with better electrical yield. A comparison of MFC and conventional anaerobic digestion performance is discussed, as well. Experimental proofs of copper removal and phosphate mobilization, following the iron reduction of FePO₄, are also reported. Full article

(This article belongs to the Special Issue Sustainable Shift to Circular Solutions for Water and Waste Management)

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10 pages, 2563 KiB

Open AccessEditor’s ChoiceArticle

Study of the Factors Limiting the Efficiency of Vertical-Type Nitride- and AlInGaP-Based Quantum-Well Micro-LEDs

by Cheng-Han Ho, Shih-Min Chen and Yuh-Renn Wu

Processes 2022, 10(3), 489; https://doi.org/10.3390/pr10030489 - 28 Feb 2022

Cited by 5 | Viewed by 4278

Abstract

The efficiency of micro-light-emitting diodes (

μ

-LEDs) depends enormously on the chip size, and this is connected to sidewall-trap-assisted nonradiative recombination. It is known that the internal quantum efficiency (IQE) of aluminum gallium indium phosphide (AlGaInP)-based red

μ

-LEDs is much lower [...] Read more.

The efficiency of micro-light-emitting diodes (

μ

-LEDs) depends enormously on the chip size, and this is connected to sidewall-trap-assisted nonradiative recombination. It is known that the internal quantum efficiency (IQE) of aluminum gallium indium phosphide (AlGaInP)-based red

μ

-LEDs is much lower than that of nitride-based

μ

-LEDs. To establish the major reasons giving rise to this huge IQE discrepancy, we examined the limiting factors in the two structures. For the nitride-based InGaN quantum wells, the influences of random alloy fluctuations were examined. A two-dimensional Poisson and drift-diffusion solver was applied to analyze these issues. Full article

(This article belongs to the Section Materials Processes)

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17 pages, 3456 KiB

Open AccessEditor’s ChoiceArticle

Climate Neutrality Concepts for the German Chemical–Pharmaceutical Industry

by Axel Schmidt, Dirk Köster and Jochen Strube

Processes 2022, 10(3), 467; https://doi.org/10.3390/pr10030467 - 25 Feb 2022

Cited by 10 | Viewed by 3622

Abstract

This paper intends to propose options for climate neutrality concepts by taking non-German international experiences and decisions made into account. Asia-Pacific and Arabic countries do have already same lessons learned by large-scale projects with regard to economic evaluations. Quite a few conceptual studies [...] Read more.

This paper intends to propose options for climate neutrality concepts by taking non-German international experiences and decisions made into account. Asia-Pacific and Arabic countries do have already same lessons learned by large-scale projects with regard to economic evaluations. Quite a few conceptual studies to generate the climate neutrality of the chemical–pharmaceutical industry in Germany have been published recently. Most of the studies differ even in magnitude but do not refer to or evaluate the other ones. These are all first theoretical feasibility studies. Experimental piloting is not far developed; only few and only stand-alone parts are operated, with no overall concepts. Economic evaluation is missing nearly completely. Economic analysis shows a factor 3 more expensive green technologies. Even if a large optimization potential of about 30% during manufacturing optimization is assumed as significant, cost increases would result. To make green products nevertheless competitive, the approach is to increase the carbon-source cost analogue, e.g., by CO₂/ton taxes by around EUR 100, which would lead to about factor 3 higher consumer prices regarding the material amount. Furthermore, some countries would not participate in such increases and would have benefits on the world market. Whether any customs-duties policy could balance that is generally under question. Such increasing costs are not imaginable for any social-political system. Therefore, the only chance to realize consequent climate neutrality is to speed up research on more efficient and economic technologies, including, e.g., reaction intensification technologies such as plasma ionization, catalyst optimization, section coupling to cement, steel and waste combustion branches as well as pinch technology integration and appropriate scheduling. In addition, digital twins and process analytical technologies for consequent process automation would help to decrease costs. All those technologies seem to lead to even less personnel, but who need to be highly educated to deal with complex integrated systems. Research and education/training has to be designed for those scenarios. Germany as a resource-poor country could benefit from its human resources. Germany is and will be an energy importing country. Full article

(This article belongs to the Special Issue Towards Autonomous Operation of Biologics and Botanicals)

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14 pages, 9949 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Faba Bean Fractions for 3D Printing of Protein-, Starch- and Fibre-Rich Foods

by Mathias Johansson, Klara Nilsson, Fanny Knab and Maud Langton

Processes 2022, 10(3), 466; https://doi.org/10.3390/pr10030466 - 25 Feb 2022

Cited by 20 | Viewed by 4833

Abstract

Food 3D printing allows for the production of personalised foods in terms of shape and nutrition. In this study, we examined whether protein-, starch- and fibre-rich fractions extracted from faba beans can be combined to produce fibre- and protein-rich printable food inks for [...] Read more.

Food 3D printing allows for the production of personalised foods in terms of shape and nutrition. In this study, we examined whether protein-, starch- and fibre-rich fractions extracted from faba beans can be combined to produce fibre- and protein-rich printable food inks for extrusion-based 3D printing. Small amplitude oscillatory shear measurements were used to characterise the inks while compression tests and scanning electron microscopy were used to characterise the freeze-dried samples. We found that rheological parameters such as storage modulus, loss tangent and yield stress were related to ink printability and shape stability. Investigations on the effect of ink composition, infill pattern (honeycomb/grid) and direction of compression on textural and microstructural properties of freeze-dried 3D-printed objects revealed no clear effect of infill pattern, but a strong effect of direction of compression. Microstructure heterogeneity seemed to be correlated with the textural properties of the printed objects. Full article

(This article belongs to the Special Issue Food Processing Technologies Applied to Cereals, Legumes, Oilseeds, Alternative Food Raw Materials and Their Derivatives)

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12 pages, 2298 KiB

Open AccessEditor’s ChoiceArticle

Investigating the Trade-Off between Design and Operational Flexibility in Continuous Manufacturing of Pharmaceutical Tablets: A Case Study of the Fluid Bed Dryer

by Sheng-Long Jiang, Lazaros G. Papageorgiou, Ian David L. Bogle and Vassilis M. Charitopoulos

Processes 2022, 10(3), 454; https://doi.org/10.3390/pr10030454 - 24 Feb 2022

Cited by 5 | Viewed by 2749

Abstract

Market globalisation, shortened patent lifetimes and the ongoing shift towards personalised medicines exert unprecedented pressure on the pharmaceutical industry. In the push for continuous pharmaceutical manufacturing, processes need to be shown to be agile and robust enough to handle variations with respect to [...] Read more.

Market globalisation, shortened patent lifetimes and the ongoing shift towards personalised medicines exert unprecedented pressure on the pharmaceutical industry. In the push for continuous pharmaceutical manufacturing, processes need to be shown to be agile and robust enough to handle variations with respect to product demands and operating conditions. In this paper we examine the use of operational envelopes to study the trade-off between the design and operational flexibility of the fluid bed dryer at the heart of a tablet manufacturing process. The operating flexibility of this unit is key to the flexibility of the full process and its supply chain. The methodology shows that for the fluid bed dryer case study there is significant effect on flexibility of the process at different drying times with the optimal obtained at 700 s. The flexibility is not affected by the change in volumetric flowrate, but only by the change in temperature. Here the method used a black box model to show how it could be done without access to the full model equation set, as this often needs to be the case in commercial settings. Full article

(This article belongs to the Special Issue Expanding the Horizons of Manufacturing: Towards Wide Integration, Smart Systems and Tools)

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23 pages, 1245 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Optimal Darwinian Selection of Microorganisms with Internal Storage

by Walid Djema, Térence Bayen and Olivier Bernard

Processes 2022, 10(3), 461; https://doi.org/10.3390/pr10030461 - 24 Feb 2022

Cited by 10 | Viewed by 1674

Abstract

In this paper, we investigate the problem of species separation in minimal time. Droop model is considered to describe the evolution of two distinct populations of microorganisms that are in competition for the same resource in a photobioreactor. We focus on an optimal [...] Read more.

In this paper, we investigate the problem of species separation in minimal time. Droop model is considered to describe the evolution of two distinct populations of microorganisms that are in competition for the same resource in a photobioreactor. We focus on an optimal control problem (OCP) subject to a five-dimensional controlled system in which the control represents the dilution rate of the chemostat. The objective is to select the desired species in minimal-time and to synthesize an optimal feedback control. This is a very challenging issue, since we are are dealing with a ten-dimensional optimality system. We provide properties of optimal controls allowing the strain of interest to dominate the population. Our analysis is based on the Pontryagin Maximum Principle (PMP), along with a thorough study of singular arcs that is crucial in the synthesis of optimal controls. These theoretical results are also extensively illustrated and validated using a direct method in optimal control (via the Bocop software for numerically solving optimal control problems). The approach is illustrated with numerical examples with microalgae, reflecting the complexity of the optimal control structure and the richness of the dynamical behavior. Full article

(This article belongs to the Special Issue Mathematical Modeling and Control of Bioprocesses)

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21 pages, 4261 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Purposely Development of the Adaptive Potential of Activated Sludge from Municipal Wastewater Treatment Plant Focused on the Treatment of Landfill Leachate

by Mihaela Belouhova, Ivaylo Yotinov, Irina Schneider, Nora Dinova, Yovana Todorova, Valentina Lyubomirova, Veronika Mihaylova, Elmira Daskalova, Stilyana Lincheva and Yana Topalova

Processes 2022, 10(3), 460; https://doi.org/10.3390/pr10030460 - 24 Feb 2022

Cited by 5 | Viewed by 3175

Abstract

Biological treatment is a key technology in landfill leachate treatment However, often its efficiency is not high enough due to the pollutants in concentrations above the critical ones. The present study aimed to investigate the adaptive responses that occur in activated sludge (AS) [...] Read more.

Biological treatment is a key technology in landfill leachate treatment However, often its efficiency is not high enough due to the pollutants in concentrations above the critical ones. The present study aimed to investigate the adaptive responses that occur in activated sludge (AS) during landfill leachate purification. A model process with AS from a municipal wastewater treatment plant and landfill leachate in increasing concentrations was constructed. The data showed that when dilutions 25 and 50 times had been applied the structure of the AS was preserved, but the COD cannot be reduced below 209 mg O₂/L. The feed of undiluted leachate destroyed the AS structure as SVI was reduced to 1 mL/g, biotic index to 1, floc size was greatly reduced and COD remained high (2526 mg O₂/L). The dominant group of protozoa was changed from attached to free-swimming ciliates. An increase of the bacterial groups responsible for the xenobiotics elimination (aerobic heterotrophs, genera Pseudomonas, Acinetobacter, Azoarcus, Thauera, Alcaligenes) was registered. This was accompanied by a significant increase in free bacteria. The obtained data showed that for optimal treatment of this type of water it is necessary to include a combination of biological treatment with another non-biological method (membrane filtration, reverse osmosis, etc.). Full article

(This article belongs to the Special Issue Sustainable Shift to Circular Solutions for Water and Waste Management)

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12 pages, 4045 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Comparative Metagenomics of Anaerobic Digester Communities Reveals Sulfidogenic and Methanogenic Microbial Subgroups in Conventional and Plug Flow Residential Septic Tank Systems

by James Naphtali, Alexander W. Y. Chan, Faizan Saleem, Enze Li, Jacob Devries and Herb E. Schellhorn

Processes 2022, 10(3), 436; https://doi.org/10.3390/pr10030436 - 22 Feb 2022

Cited by 6 | Viewed by 3373

Abstract

On-site wastewater treatment systems (OWTS) are primarily monitored using physiochemical factors, including chemical oxygen demand (COD) and residual total suspended solids (TSS), which are indirect measures of the microbial action during the anaerobic digestion process. Changes in anaerobic digester microbial communities can alter [...] Read more.

On-site wastewater treatment systems (OWTS) are primarily monitored using physiochemical factors, including chemical oxygen demand (COD) and residual total suspended solids (TSS), which are indirect measures of the microbial action during the anaerobic digestion process. Changes in anaerobic digester microbial communities can alter the digester performance, but this information cannot be directly obtained from traditional physicochemical indicators. The potential of metagenomic DNA sequencing as a tool for taxonomic and functional profiling of microbial communities was examined in both common conventional and plug flow-type anaerobic digesters (single-pass and recirculating). Compared to conventional digesters, plug flow-type digesters had higher relative levels of sulfate-reducing bacteria (Desulfovibrio spp.) and hydrogenotrophic methanogens (Methanospirillum spp.). In contrast, recirculating anaerobic digesters were enriched with denitrifier bacteria and hydrogenotrophic methanogens, and both were significantly correlated with physicochemical factors such as COD and TSS. Stratification of microbial communities was observed along the digester treatment process according to hydrolytic, acidogenic, acetogenic, and methanogenic subgroups. These results indicate that the high-throughput DNA sequencing may be useful as a monitoring tool to characterize the changes in bacterial communities and the functional profile due to differences in digester design in on-site systems. Full article

(This article belongs to the Special Issue Wastewater and Waste Treatment: Overview, Challenges and Current Trends)

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10 pages, 622 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Bulk Process for Enrichment of Capsinoids from Capsicum Fruit

by Charles L. Cantrell and Robert L. Jarret

Processes 2022, 10(2), 305; https://doi.org/10.3390/pr10020305 - 4 Feb 2022

Cited by 4 | Viewed by 2562

Abstract

Various methods to synthesize capsinoids (the nonpungent analogs of capsaicinoids) from precursor molecules have been reported. Capsinoids are also naturally present, at typically low concentrations, in the fruit of many Capsicum species and genotypes. However, they are also present in the fruit of [...] Read more.

Various methods to synthesize capsinoids (the nonpungent analogs of capsaicinoids) from precursor molecules have been reported. Capsinoids are also naturally present, at typically low concentrations, in the fruit of many Capsicum species and genotypes. However, they are also present in the fruit of select genotypes at high concentrations. The fruit of high-capsiate genotypes represents a commercial source of these compounds. To date, no method has been published that efficiently extracts and purifies capsinoids from Capsicum fruit in a rapid and simple bulk process. This study evaluated the efficacy of various organic solvents for the extraction of capsinoids from dried Capsicum annuum fruit. Among the organic solvents evaluated, pentane appeared to provide a good combination of both recovery and purity. A subsequent liquid/liquid extraction step, utilizing pentane and acetonitrile, resulted in 26.3% (wt/wt) capsiate and 19.4% (wt/wt) dihydrocapsiate for a combined capsinoids yield of 45.7% (wt/wt). A third step, involving a rapid hp20ss chromatography column using a water/acetonitrile gradient, resulted in a combined capsinoids yield of 96.6% (wt/wt). Full article

(This article belongs to the Section Biological Processes and Systems)

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12 pages, 2851 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effects of Biochar Application on Vegetation Growth, Cover, and Erosion Potential in Sloped Cultivated Soil Derived from Mudstone

by Ming-Hsi Lee, Huan-Hsuan Lin and Shih-Hao Jien

Processes 2022, 10(2), 306; https://doi.org/10.3390/pr10020306 - 4 Feb 2022

Cited by 5 | Viewed by 2551

Abstract

Soil degradation is a crucial problem, particularly in tropical and subtropical areas. Prevention or reduction of soil erosion requires strategies based on thorough rapid vegetation cover (VC) and favorable soil quality in subtropical and tropical areas. This study applied wood biochar (WB) and [...] Read more.

Soil degradation is a crucial problem, particularly in tropical and subtropical areas. Prevention or reduction of soil erosion requires strategies based on thorough rapid vegetation cover (VC) and favorable soil quality in subtropical and tropical areas. This study applied wood biochar (WB) and rice husk biochar (RHB) in a mudstone soil, which is widely distributed in Southern Taiwan, to investigate the effects of biochar application on soil erosion and vegetation restoration. The standard erosion unit plots (22.13 m in length and 9% in slope gradient) were set up to determine the relationship among soil losses, VC, and natural rainfall characteristics with and without biochar application. The results indicated that biochar application increased the growth rate (identified by cover ratio) of Bahia grass (Paspalum notatum Flüggé) by 2–2.6 times within 40 days compared with control (without biochar application) and increased VC by 20% after 120 days of treatment. The biochar application could effectively reduce soil losses by 60% at least in the mudstone soil. A well-predicted regression function of soil loss with VC and rainfall kinetic energy was established (amount of soil lost = −0.435 × ln VC + 0.54 × RKE, r = 0.89, p < 0.01). Full article

(This article belongs to the Section Environmental and Green Processes)

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18 pages, 3838 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Manno-Oligosaccharide Production from Biomass Hydrolysis by Using Endo-1,4-β-Mannanase (ManNj6-379) from Nonomuraea jabiensis ID06-379

by Shanti Ratnakomala, Prihardi Kahar, Norimasa Kashiwagi, JaeMin Lee, Motonori Kudou, Hana Matsumoto, Pamella Apriliana, Yopi Yopi, Bambang Prasetya, Chiaki Ogino and Akihiko Kondo

Processes 2022, 10(2), 269; https://doi.org/10.3390/pr10020269 - 29 Jan 2022

Cited by 5 | Viewed by 3647

Abstract

A novel endo-β-1,4-mannanase gene was cloned from a novel actinomycetes, Nonomuraea jabiensis ID06-379, isolated from soil, overexpressed as an extracellular protein (47.8 kDa) in Streptomyces lividans 1326. This new endo-1,4-β-mannanase gene (manNj6-379) is encoded by 445-amino acids. The ManNj6-379 consists of [...] Read more.

A novel endo-β-1,4-mannanase gene was cloned from a novel actinomycetes, Nonomuraea jabiensis ID06-379, isolated from soil, overexpressed as an extracellular protein (47.8 kDa) in Streptomyces lividans 1326. This new endo-1,4-β-mannanase gene (manNj6-379) is encoded by 445-amino acids. The ManNj6-379 consists of a 28-residue signal peptide and a carbohydrate-binding module of family 2 belonging to the glycoside hydrolase (GH) family 5, with 59–77% identity to GH5 mannan endo-1,4-β-mannanase. The recombinant ManNj6-379 displayed an optimal pH of 6.5 with pH stability ranging between 5.5 and 7.0 and was stable for 120 min at 50 °C and lower temperatures. The optimal temperature for activity was 70 °C. An enzymatic hydrolysis assay revealed that ManNj6-379 could hydrolyze commercial β-mannan and biomass containing mannan. Full article

(This article belongs to the Section Biological Processes and Systems)

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8 pages, 1214 KiB

Open AccessEditor’s ChoiceCommunication

Functional Compounds from Banana Peel Used to Decrease Oxidative Stress Effects

by Ionela Avram, Florentina Gatea and Emanuel Vamanu

Processes 2022, 10(2), 248; https://doi.org/10.3390/pr10020248 - 27 Jan 2022

Cited by 10 | Viewed by 8681

Abstract

Banana peel, a little-used waste, contains a high amount of biologically active compounds. The aim of the study is to demonstrate in vitro, the antioxidant, cytotoxic, and antimicrobial effects of hydroalcoholic extracts from yellow (BP) and red (BPR) banana peels. The analysis [...] Read more.

Banana peel, a little-used waste, contains a high amount of biologically active compounds. The aim of the study is to demonstrate in vitro, the antioxidant, cytotoxic, and antimicrobial effects of hydroalcoholic extracts from yellow (BP) and red (BPR) banana peels. The analysis of the extracts by Capillary Zone Electrophoresis (CZE) has confirmed the presence of several bioactive compounds. BPR has a higher in vitro antioxidant activity than BP, which correlates with a significant cytotoxic, antimicrobial effect, with a UVA/UVB rate of 0.9. In the case of BPR, the results confirm the presence of isoquercitrin and kaempferol in a 1:3 ratio. The bioactive compounds from the extracts have shown a different interaction with HCT-8 cell lines and with tested bacterial strains with pathogenic properties. The HCA analysis proved the biological value of BPR to reduce oxidative stress and its potential use in natural products. Full article

(This article belongs to the Special Issue Bioactive Compounds from Food Waste and By-Products)

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13 pages, 864 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Valorising Agricultural Residues through Pelletisation

by Daniele Duca, Vittorio Maceratesi, Sara Fabrizi and Giuseppe Toscano

Processes 2022, 10(2), 232; https://doi.org/10.3390/pr10020232 - 26 Jan 2022

Cited by 6 | Viewed by 3294

Abstract

The agricultural sector and its related production chains are good sources of residual biomass. Olive and vineyard pruning residues are present in high quantities in Italy. The limited bulk and energy densities of these biomass materials affect the harvesting and logistic costs, limiting [...] Read more.

The agricultural sector and its related production chains are good sources of residual biomass. Olive and vineyard pruning residues are present in high quantities in Italy. The limited bulk and energy densities of these biomass materials affect the harvesting and logistic costs, limiting energy and environmental sustainability. Pelletisation is the most efficient process for increasing bulk and energy densities. This study evaluates the pelletisation process of olive and vineyard prunings, pure, or blended with variable quantities of spruce sawdust. A 15 kW pelletisation system was chosen, in line with production at the farm level. The most important quality parameters of the produced agripellets were analyzed. The results of this investigation suggest that blending could valorize other biomass materials less suitable for pelletisation and reach the pellet quality required by Italian technical standards. The addition of pruning residues to spruce sawdust leads to an improvement in durability. Spruce sawdust pellets have a durability value of 78.4%. Adding 20% of olive prunings (S80O20) increases this value to 92.2, while adding 20% vineyard prunings (S80V20) increases this value up to 90.3. The addition of 20% of pruning residues significantly increased the length and decreased fines. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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12 pages, 1574 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Applicability of Food Grade Modified Starches as a Carrier of Microelements

by Hanna Śmigielska, Wioletta Błaszczak and Grażyna Lewandowicz

Processes 2022, 10(2), 235; https://doi.org/10.3390/pr10020235 - 26 Jan 2022

Cited by 5 | Viewed by 3746

Abstract

Growth in the human population and intensive, large-scale farming results in a lowering in the quality of nutrition. An oversupply of food energy is often accompanied with a deficiency in micronutrients. To address this problem, the food industry provides products enriched with bioactive [...] Read more.

Growth in the human population and intensive, large-scale farming results in a lowering in the quality of nutrition. An oversupply of food energy is often accompanied with a deficiency in micronutrients. To address this problem, the food industry provides products enriched with bioactive substances. The main challenge of this technology is the even distribution of micronutrients in the matrix of the fortified food. A possible solution to this challenge is to use stable and effective carriers. The aim of this work was to verify the applicability of native potato starch and modified starches (commonly used in the food industry) as carriers for microelements. Adsorptions were carried out in starch suspensions at a temperature below gelatinisation. The native potato starch and the modified starches (E 1404, E 1412, E 1420, and E 1422) were assessed for their effectiveness in adsorbing copper, iron, and zinc sulphates or gluconates. Pasting characteristics were analysed using a Brabender viscograph and light microscopy. Furthermore, texture profile analysis of starch-based desserts was carried out with the use of the tested carriers. Starch in both its native and modified forms was able to effectively adsorb copper, iron, and zinc ions. Adsorption was more efficient when using modified starches containing hydrophilic carboxyl groups. The effectiveness of adsorption with oxidised starches increased with an increase in the degree of substitution. Starches containing more hydrophobic acetyl groups were less effective as adsorbents of microelements. The cation adsorption efficiency decreased in the order copper > iron > zinc, and sulphates were better adsorbed than gluconates. Copper ions influenced the pasting characteristics of the oxidised starches, and these effects were dependent on the degree of substitution with carboxyl groups. As observed by light microscopy, the presence of copper ions changes the interaction between the starch macromolecules and water. However, the above-mentioned changes did not significantly affect the texture of traditional sweet desserts. Starch, particularly its oxidised derivatives containing hydrophilic oxidised groups, can be recommended as a carrier of microelements for food fortification. The use of modified starches containing relatively hydrophobic acetyl groups is not appropriate because they absorb microelements less efficiently than native starch. Full article

(This article belongs to the Special Issue Rheological Properties and Structure of Starches: Processing and Applications)

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13 pages, 800 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Beetroot By-Product as a Functional Ingredient for Obtaining Value-Added Mayonnaise

by Silvia Lazăr (Mistrianu), Oana Emilia Constantin, Georgiana Horincar, Doina Georgeta Andronoiu, Nicoleta Stănciuc, Claudia Muresan and Gabriela Râpeanu

Processes 2022, 10(2), 227; https://doi.org/10.3390/pr10020227 - 25 Jan 2022

Cited by 23 | Viewed by 6044

Abstract

Beetroot peel is a by-product obtained during the processing of beetroots and is an essential source of bioactive substances beneficial to health. This study used antioxidant-rich beetroot peels powder (BPP) in different concentrations (1.5, 3, 5, and 7%) to obtain value-added mayonnaise. The [...] Read more.

Beetroot peel is a by-product obtained during the processing of beetroots and is an essential source of bioactive substances beneficial to health. This study used antioxidant-rich beetroot peels powder (BPP) in different concentrations (1.5, 3, 5, and 7%) to obtain value-added mayonnaise. The impact of BPP on the phytochemical composition, sensory characteristics, viscosity, color, and textural properties of the mayonnaises were also investigated. The BPP was characterized by a high betalain content (1.18 ± 0.03 mg/g DW) and rich polyphenolic content (225.36 ± 1.97 mg GAE/g DW) and showed high antioxidant activity. The purple-red colored powders added to the mayonnaise allowed a significant increase in total phenolic content and the antioxidant activity of purple-red colored powders added to the mayonnaise. The total color difference ΔE value in the mayonnaise samples increased with extract concentration. The instrumental texture analysis findings revealed that BPP addition to the mayonnaise increased the firmness, adhesiveness, and cohesiveness and improved the samples’ chewiness. The viscosity of mayonnaise was also significantly improved. The inclusion of BPP improved the color, according to sensory evaluation and overall acceptability of the mayonnaise formulation. The results give a novel formulation and technological insights into the influence of BPP-powder enrichment on the physical, sensory, and textural qualities of mayonnaise. BPP could be employed as a natural ingredient in several value-added emulsions, including sauces, mayonnaise, dressings, and creams. Full article

(This article belongs to the Special Issue Recent Advances in Natural Bioactive Compound Valorization)

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21 pages, 3353 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Advancements in the Conversion of Lipid-Rich Biowastes and Lignocellulosic Residues into High-Quality Road and Jet Biofuels Using Nanomaterials as Catalysts

by Max J. A. Romero, Daniele Duca and Giuseppe Toscano

Processes 2022, 10(2), 187; https://doi.org/10.3390/pr10020187 - 18 Jan 2022

Cited by 6 | Viewed by 3621

Abstract

At present, the majority of available road and jet biofuels are produced from oleochemical feedstocks that include vegetable oils and biowastes such as waste cooking oils and animal fats. Additionally, one of the most promising ways to achieve long-term environmental goals is to [...] Read more.

At present, the majority of available road and jet biofuels are produced from oleochemical feedstocks that include vegetable oils and biowastes such as waste cooking oils and animal fats. Additionally, one of the most promising ways to achieve long-term environmental goals is to sustainably use lignocellulosic residues. These resources must be treated through a deoxygenation process and subsequent upgrading processes to obtain high-quality road and jet biofuels. Accordingly, in this review, we explore recent advancements in the deoxygenation of oleochemical and lignocellulosic feedstocks in the absence of hydrogen to produce high-quality road and jet biofuels, mainly focusing on the use of nanomaterials as catalysts and the valorization of lipid-rich biowastes and lignocellulosic residues. As a result, we found that regardless of the catalyst particle size, the coexistence of basic sites and weak/medium acid sites is highly important in catalytic systems. Basic sites can enhance the removal of oxygenates via decarboxylation and decarbonylation reactions and inhibit coke formation, while weak/medium acid sites can enhance the cracking reaction. Additionally, the extraction of value-added derivatives from lignocellulosic residues and their subsequent upgrade require the use of advanced methods such as the lignin-first approach and condensation reactions. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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15 pages, 7938 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Impact of Silica Additions on the Phase Composition and Electrical Transport Properties of Ruddlesden-Popper La₂NiO_4+δ Mixed Conducting Ceramics

by Kiryl Zakharchuk, Aleksandr Bamburov, Eugene N. Naumovich, Miguel A. Vieira and Aleksey A. Yaremchenko

Processes 2022, 10(1), 82; https://doi.org/10.3390/pr10010082 - 31 Dec 2021

Cited by 3 | Viewed by 2602

Abstract

The present work explores the possibility of incorporation of silicon into the crystal structure of Ruddlesden-Popper La₂NiO_4+δ mixed conducting ceramics with the aim to improve the chemical compatibility with lanthanum silicate-based solid electrolytes. Ceramics with the nominal composition La₂ [...] Read more.

The present work explores the possibility of incorporation of silicon into the crystal structure of Ruddlesden-Popper La₂NiO_4+δ mixed conducting ceramics with the aim to improve the chemical compatibility with lanthanum silicate-based solid electrolytes. Ceramics with the nominal composition La₂Ni_1−ySi_yO_4+δ (y = 0, 0.02 and 0.05) were prepared by the glycine nitrate combustion technique and sintered at 1450 °C. While minor changes in the lattice parameters of the tetragonal K₂NiF₄-type lattice may suggest incorporation of a small fraction of Si into the Ni sublattice, combined XRD and SEM/EDS studies indicate that this fraction is very limited (≪2 at.%, if any). Instead, additions of silica result in segregation of apatite-type La_10−xSi₆O_26+δ and La₂O₃ secondary phases as confirmed experimentally and supported by the static lattice simulations. Both total electrical conductivity and oxygen-ionic transport in La₂NiO_4+δ ceramics are suppressed by silica additions. The preferential reactivity of silica with lanthanum oxide opens a possibility to improve the compatibility between lanthanum silicate-based solid electrolytes and La₂NiO_4+δ-based electrodes by appropriate surface modifications. The promising potential of this approach is supported by preliminary tests of electrodes infiltrated with lanthanum oxide. Full article

(This article belongs to the Section Energy Systems)

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18 pages, 11247 KiB

Open AccessEditor’s ChoiceArticle

Optimal Magnetic Graphite Heater Design for Impurity Control in Single-Crystal Si Grower Using Crystal Growth Simulation

by Hye Jun Jeon, Hyeonwook Park, Salh Alhammadi, Jae Hak Jung and Woo Kyoung Kim

Processes 2022, 10(1), 70; https://doi.org/10.3390/pr10010070 - 30 Dec 2021

Cited by 1 | Viewed by 3216

Abstract

In this paper, we report a successfully modified single-crystal Si growth furnace for impurity control. Four types of arbitrary magnetic heater (AMGH) systems with 3, 4, 5, and poly parts were designed in a coil shape and analyzed using crystal growth simulation. The [...] Read more.

In this paper, we report a successfully modified single-crystal Si growth furnace for impurity control. Four types of arbitrary magnetic heater (AMGH) systems with 3, 4, 5, and poly parts were designed in a coil shape and analyzed using crystal growth simulation. The concentration of oxygen impurities in single-crystal Si ingots was compared among the designed AMGHs and a normal graphite heater (NGH). The designed AMGHs were confirmed to be able to control turbulence and convection in a molten state, which created a vortex that influenced the oxygen direction near the melt–crystal interface. It was confirmed that replacing NGH with AMGHs resulted in a reduction in the average oxygen concentration at the Si melt–crystal interface by approximately 4.8%. Full article

(This article belongs to the Special Issue Design and Optimization in Process Engineering)

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21 pages, 5147 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Treatment of Winery Wastewater with a Combination of Adsorption and Thermocatalytic Processes

by Nuno Jorge, Ana R. Teixeira, Vanessa Guimarães, Marco S. Lucas and José A. Peres

Processes 2022, 10(1), 75; https://doi.org/10.3390/pr10010075 - 30 Dec 2021

Cited by 18 | Viewed by 3155

Abstract

The release of winery wastewater (WW) into the environment, without proper treatment, can cause severe problems to freshwater quality and natural fauna and flora. Therefore, in this work a treatment process was studied, combining adsorption and thermocatalytic oxidation processes. In a more specific [...] Read more.

The release of winery wastewater (WW) into the environment, without proper treatment, can cause severe problems to freshwater quality and natural fauna and flora. Therefore, in this work a treatment process was studied, combining adsorption and thermocatalytic oxidation processes. In a more specific way, it optimized the combination of activated sodium bentonite (Na-Mt) and potassium persulfate (KPS)/sodium percarbonate (SPC) as oxidant agents. With the combination of best operational conditions of adsorption ([Na-Mt] = 5.0 g/L, pH = 3.0, V = 500 mL, agitation 350 rpm, T = 298 K, t = 24 h) and thermocatalytic oxidation processes (

S_{2} O_{8}^{2 -}

/H₂O₂ ratio = 1:0.25,

S_{2} O_{8}^{2 -}

/H₂O₂ dosage = 0.1:0.025 (g/g), pH = 7.0, T = 343 K, agitation 350 rpm, t = 2 h), a total organic carbon, chemical oxygen demand and total polyphenols removal of 76.7, 81.4 and >99% was achieved, respectively. Finally, it was evaluated the effect of the treatment processes in the germination index (GI) of different plant seeds. A GI > 80% was achieved, showing a low phytotoxicity effect of the processes applied in the winery wastewater treatment. Full article

(This article belongs to the Section Environmental and Green Processes)

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21 pages, 7269 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Thermal Behavior of Ceramic Bodies Based on Estonian Clay from the Arumetsa Deposit with Oil Shale Ash and Clinker Dust Additives

by Tiit Kaljuvee, Igor Štubňa, Tomáš Húlan, Mai Uibu, Marve Einard, Rainer Traksmaa, Mart Viljus, Jekaterina Jefimova and Andres Trikkel

Processes 2022, 10(1), 46; https://doi.org/10.3390/pr10010046 - 27 Dec 2021

Cited by 8 | Viewed by 3458

Abstract

The thermal behavior of green clay samples from the Arumetsa and Füzérradvány deposits (Hungary) and the influence of two new types of Estonian oil shale (OS) ashes and cement bypass dust (clinker dust) additives on it were the objectives of this study. Thermal [...] Read more.

The thermal behavior of green clay samples from the Arumetsa and Füzérradvány deposits (Hungary) and the influence of two new types of Estonian oil shale (OS) ashes and cement bypass dust (clinker dust) additives on it were the objectives of this study. Thermal and thermo-dilatometric analysis methods were applied using a Setaram Setsys 1750 thermoanalyzer coupled with a Pfeiffer Omnistar spectrometer and a Setaram Setsys 1750 CS Evolution dilatometer. The kinetic parameters were calculated based on the differential isoconversional method of Friedman. The results of the thermal analysis of clays and blends indicated the emission of physically bound water at 200–250 °C. At temperatures from 200–250 °C to 550–600 °C the release of water is caused by oxidation of organic matter and dehydroxylation of different clay minerals like illite, illite-smectite, mica and kaolin. From blends, in addition, also from the decomposition of portlandite. The emission of CO₂ at these temperatures was a result of the oxidation of organic matter contained in the clays. In the temperature range from 550–600 °C to 800–900 °C, the mass loss was caused by ongoing dehydroxylation processes in clay minerals but was mainly due to the decomposition of the carbonates contained in the OS ashes and clinker dust. These processes were accompanied by contraction and expansion of the ceramic bodies with the corresponding changes in the SSA and porosity values of the samples. Therefore, the decomposition of the clays took place in one step which blends in two steps. At first, dehydroxylation of the clay minerals occurs, followed by decomposition of the carbonates. The value of the conversion-dependent activation energy E along the reaction progress α varied for the Arumetsa and illitic clay between 75–182 and 9–206 kJ mol⁻¹, respectively. For the blends based on Arumetsa and illitic clay, the activation energy of the first step varied between 14–193 and 5–205 kJ mol⁻¹, and for the second step, it was between 15–390 and 135–235 kJ mol⁻¹, respectively, indicating the complex mechanism of the processes. Full article

(This article belongs to the Special Issue Recent Advances in Ceramic Materials: Processing, Characterization and Applications)

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18 pages, 4260 KiB

Open AccessEditor’s ChoiceArticle

A Sustainable Process to Produce Manganese and Its Alloys through Hydrogen and Aluminothermic Reduction

by Jafar Safarian

Processes 2022, 10(1), 27; https://doi.org/10.3390/pr10010027 - 24 Dec 2021

Cited by 11 | Viewed by 6782

Abstract

Hydrogen and aluminum were used to produce manganese, aluminum–manganese (AlMn) and ferromanganese (FeMn) alloys through experimental work, and mass and energy balances. Oxide pellets were made from Mn oxide and CaO powder, followed by pre-reduction by hydrogen. The reduced MnO pellets were then [...] Read more.

Hydrogen and aluminum were used to produce manganese, aluminum–manganese (AlMn) and ferromanganese (FeMn) alloys through experimental work, and mass and energy balances. Oxide pellets were made from Mn oxide and CaO powder, followed by pre-reduction by hydrogen. The reduced MnO pellets were then smelted and reduced at elevated temperatures through CaO flux and Al reductant addition, yielding metallic Mn. Changing the amount of the added Al for the aluminothermic reduction, with or without iron addition led to the production of Mn metal, AlMn alloy and FeMn alloy. Mass and energy balances were carried out for three scenarios to produce these metal products with feasible material flows. An integrated process with three main steps is introduced; a pre-reduction unit to pre-reduce Mn ore, a smelting-aluminothermic reduction unit to produce metals from the pre-reduced ore, and a gas treatment unit to do heat recovery and hydrogen looping from the pre-reduction process gas. It is shown that the process is sustainable regarding the valorization of industrial waste and the energy consumptions for Mn and its alloys production via this process are lower than current commercial processes. Ferromanganese production by this process will prevent the emission of about 1.5 t CO₂/t metal. Full article

(This article belongs to the Topic Processing, Analysis, Modelling and Mechanics of Materials and Structures)

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8 pages, 2800 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The Effects of the Acid Treatment of ZrB₂ Particles on Their Purity and Aqueous Dispersibility

by Jinuk Choi and Gye Seok An

Processes 2022, 10(1), 18; https://doi.org/10.3390/pr10010018 - 23 Dec 2021

Cited by 2 | Viewed by 2594

Abstract

Oxide impurities such as boria (B₂O₃) and zirconia (ZrO₂) on the surfaces of zirconium diboride (ZrB₂) particles are known to limit their sinterability. Among the impurities, B₂O₃ on the surface of ZrB [...] Read more.

Oxide impurities such as boria (B₂O₃) and zirconia (ZrO₂) on the surfaces of zirconium diboride (ZrB₂) particles are known to limit their sinterability. Among the impurities, B₂O₃ on the surface of ZrB₂ particles could be easily removed by methanol or hydrofluoric acid. However, the remaining ZrO₂ still gave negative influences on the sinterability. In this study, ZrB₂ particles were treated with various acids to remove oxide impurities on their surfaces. The acid treatments were found to vary in efficacy, according to acid type, and affect the crystallinity and morphology of ZrB₂ particles to varying degrees, in some cases forming additional impurities. In particular, the change in the oxygen content of the ZrB₂ particles induced by acid treatment was found to depend on the type of acid. The results of the acid treatments were compared which revealed that HNO₃ treatment optimizes the purity of ZrB₂ particles. In addition, the effects of acid treatment on the surface properties of ZrB₂ particles were considered. In particular, the correlation between the surface properties of the acid-treated ZrB₂ particles and their dispersibility in aqueous solution was investigated. Full article

(This article belongs to the Special Issue Recent Advances in Ceramic Materials: Processing, Characterization and Applications)

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20 pages, 5105 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Oscillating Combustion—Primary Measure to Reduce Nitrogen Oxide in a Grate Furnace–Experiments and Simulations

by Hans-Joachim Gehrmann, Bo Jaeger, Siegmar Wirtz, Viktor Scherer, Krasimir Aleksandrov, Manuela Hauser, Dieter Stapf, Gregor Pollmeier and Philipp Danz

Processes 2021, 9(12), 2210; https://doi.org/10.3390/pr9122210 - 8 Dec 2021

Cited by 9 | Viewed by 3148

Abstract

The emission from industries and the mobility sector is under strong legal regulations in many countries worldwide. In Germany, the amendment to the 17th BlmSchV (Federal pollution control ordinance), which has been in force for waste incineration plants since 2013, has given rise [...] Read more.

The emission from industries and the mobility sector is under strong legal regulations in many countries worldwide. In Germany, the amendment to the 17th BlmSchV (Federal pollution control ordinance), which has been in force for waste incineration plants since 2013, has given rise to a new limit for nitrogen oxides of 150 mg/m³ as the daily mean level from 2019 on. A similar focus is on biomass-fired plants. According to the MCP (medium combustion plant) guideline of the EU, as a consequence, existing plants are required to either increase their consumption of ammonia water for nitrogen oxide reduction (SNCR process) or back fit SCR catalysts as secondary measures, which is a costly procedure. This paper presents a novel two-stage process in which an oscillating supply of secondary air allows nitrogen oxides to be reduced by approx. 50% at a good burnout level, which may obviate the need for secondary measures. Besides experimental investigations in a fixed bed reactor, CFD simulations confirm a high potential for reduction of nitrogen oxides. Together with the company POLZENITH, this process is under development for scale-up in a biomass incineration plant as a next step. Full article

(This article belongs to the Special Issue Characterization of Emissions from Fuel Combustion)

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13 pages, 3365 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Microwave Dielectric Properties of β-CaSiO₃ Glass–Ceramics Prepared Using Two-Step Heat Treatment

by Jin-Seok Baek, Nak-Beom Jo and Eung-Soo Kim

Processes 2021, 9(12), 2180; https://doi.org/10.3390/pr9122180 - 3 Dec 2021

Cited by 7 | Viewed by 2719

Abstract

The microwave dielectric properties of β-CaSiO₃ glass–ceramics are compared with those of α-CaSiO₃ ceramics. β-CaSiO₃ is prepared using glass–ceramics method with two-step heat treatment at 730 °C for 1–7 h and at 900 °C for 3 h, and α-CaSiO₃ [...] Read more.

The microwave dielectric properties of β-CaSiO₃ glass–ceramics are compared with those of α-CaSiO₃ ceramics. β-CaSiO₃ is prepared using glass–ceramics method with two-step heat treatment at 730 °C for 1–7 h and at 900 °C for 3 h, and α-CaSiO₃ is prepared using conventional solid-state reaction and sintered at 1460–1500 °C for 3 h. With increasing holding time at 730 °C, the degree of crystallisation and Qf of the β-CaSiO₃ glass–ceramics increased. The β-CaSiO₃ specimens heat-treated at 730 °C for 3 h and 900 °C for 3 h exhibit the following dielectric properties: K = 6.57, TCF = −36.22 ppm/°C, and Qf = 52,400 GHz (highest) for the entire range of heat treatment conditions. The Qf difference between β-CaSiO₃ and α-CaSiO₃ could be explained by the bond characteristics using Rietveld refinement. FT-IR analysis shows that the Ca–O bond is the dominant factor for the Qf of CaSiO₃ ceramics compared to the Si–O bond. The higher Qf of β-CaSiO₃ than that of α-CaSiO₃ can be attributed to the higher bond strength of Ca–O for β-CaSiO₃ than that for α-CaSiO₃. Full article

(This article belongs to the Special Issue Recent Advances in Ceramic Materials: Processing, Characterization and Applications)

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16 pages, 8547 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Large Eddy Simulation of Leakage Flow in a Stepped Labyrinth Seal

by Ji-Hwan Kim and Joon Ahn

Processes 2021, 9(12), 2179; https://doi.org/10.3390/pr9122179 - 2 Dec 2021

Cited by 5 | Viewed by 2770

Abstract

Large eddy simulation (LES) and Reynolds averaged Navier-Stokes simulation (RANS) of leakage flow in straight-through and stepped labyrinth seals were performed in order to compare their performances in sealing the secondary flow passage of the gas turbine based on the respective discharge coefficients. [...] Read more.

Large eddy simulation (LES) and Reynolds averaged Navier-Stokes simulation (RANS) of leakage flow in straight-through and stepped labyrinth seals were performed in order to compare their performances in sealing the secondary flow passage of the gas turbine based on the respective discharge coefficients. The results indicate a 17.8% higher leakage prevention performance for the stepped seal relative to that of the straight seal. Further, while the LES predicts an ~7% reduction in the discharge coefficient due to shaft rotation, this effect is underestimated by the RANS. Moreover, the LES correctly predicts a laminarized flow pattern in the clearance, whereas the RANS overestimates the turbulence kinetic energy. In addition, a turbulence kinetic energy spectrum analysis was performed based on the vorticity at selected points in order to identify the flow structure that has a dominant influence on the oscillation of the discharge coefficient. This analysis also enabled identification of the changes in the flow structure due to shaft rotation. Full article

(This article belongs to the Section Manufacturing Processes and Systems)

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22 pages, 11322 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Electrochemical Performance of Iron-Doped Cobalt Oxide Hierarchical Nanostructure

by Deepa Guragain, Sunil Karna, Jonghyun Choi, Romakanta Bhattarai, Tej P. Poudel, Ram Krishna Gupta, Xiao Shen and Sanjay R. Mishra

Processes 2021, 9(12), 2176; https://doi.org/10.3390/pr9122176 - 2 Dec 2021

Cited by 18 | Viewed by 4292

Abstract

In this study, hydrothermally produced Fe-doped Co₃O₄ nanostructured particles are investigated as electrocatalysts for the water-splitting process and electrode materials for supercapacitor devices. The results of the experiments demonstrated that the surface area, specific capacitance, and electrochemical performance of Co [...] Read more.

In this study, hydrothermally produced Fe-doped Co₃O₄ nanostructured particles are investigated as electrocatalysts for the water-splitting process and electrode materials for supercapacitor devices. The results of the experiments demonstrated that the surface area, specific capacitance, and electrochemical performance of Co₃O₄ are all influenced by Fe³⁺ content. The Fe_xCo_3-xO₄ with x = 1 sample exhibits a higher BET surface (87.45 m²/g) than that of the pristine Co₃O₄ (59.4 m²/g). Electrochemical measurements of the electrode carried out in 3 M KOH reveal a high specific capacitance of 153 F/g at a current density of 1 A/g for x = 0.6 and 684 F/g at a 2 mV/s scan rate for x = 1.0 samples. In terms of electrocatalytic performance, the electrode (x = 1.0) displayed a low overpotential of 266 mV (at a current density of 10 mA/cm²) along with 52 mV/dec Tafel slopes in the oxygen evolution reaction. Additionally, the overpotential of 132 mV (at a current density of 10 mA/cm²) and 109 mV with 52 mV/dec Tafel slope were obtained for x = 0.6 sample towards hydrogen evolution reaction (HER). According to electrochemical impedance spectroscopy (EIS) measurements and the density functional theory (DFT) study, the addition of Fe³⁺ increased the conductivity at the electrode–electrolyte interface, which substantially impacted the high activity of the iron-doped cobalt oxide. The electrochemical results revealed that the mesoporous Fe-doped Co₃O₄ nanostructure could be used as potential electrode material in the high-performance electrochemical capacitor and water-splitting catalysts. Full article

(This article belongs to the Special Issue Computational Catalysts and Materials Design for Energy Conversion and Storage)

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10 pages, 3507 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Kinetic Behavior of Fabricated CuO/ZrO₂ Oxygen Carriers for Chemical Looping Oxygen Uncoupling

by Young Ku, Chia-Wei Chang, Shr-Han Shiu, Hsuan-Chih Wu and Niels Michiel Moed

Processes 2021, 9(12), 2156; https://doi.org/10.3390/pr9122156 - 29 Nov 2021

Cited by 3 | Viewed by 1616

Abstract

Chemical looping with oxygen uncoupling (CLOU) is an innovative alternative to conventional combustion. CuO/ZrO₂ oxygen carriers were tested in this system for their effectiveness and resilience. Cupric oxide (CuO) was demonstrated to be a reliable oxygen carrier for oxygen-uncoupling with consistent recyclability [...] Read more.

Chemical looping with oxygen uncoupling (CLOU) is an innovative alternative to conventional combustion. CuO/ZrO₂ oxygen carriers were tested in this system for their effectiveness and resilience. Cupric oxide (CuO) was demonstrated to be a reliable oxygen carrier for oxygen-uncoupling with consistent recyclability even after 50 redox cycles in a thermogravimetric analyzer (TGA). The reduction of CuO to generate Cu₂O and oxygen was observed to be improved markedly for experiments operated at higher temperatures; however, the oxidation of Cu₂O by air to generate CuO was hindered for experiments carried out at elevated temperatures. The reduction rate of fabricated CuO/ZrO₂ particles containing 40% CuO was enhanced with increasing temperature and decreased with increasing particle size for experiments operated in a fixed bed reactor. The geometrical contraction and Avrami-Erofe’ev models were demonstrated to be appropriate for describing the reduction and oxidation of CuO/ZrO₂, respectively. The activation energies for the reduction and oxidation were determined to be 250.6 kJ/mol and 57.6 kJ/mol, respectively, based on experimental results in the temperature range between 850 and 1000 °C. Full article

(This article belongs to the Special Issue Characterization of Emissions from Fuel Combustion)

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19 pages, 6692 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Measurement of Heat Transfer and Flow Resistance for a Packed Bed of Horticultural Products with the Implementation of a Single Blow Technique

by Adam Łapiński, Kamil Śmierciew, Huiming Zou and Dariusz Butrymowicz

Processes 2021, 9(12), 2151; https://doi.org/10.3390/pr9122151 - 28 Nov 2021

Viewed by 2145

Abstract

This paper provides the practical implementation of the single blow technique as an effective approach of average convective heat transfer coefficient measurement for a packed bed of horticultural products. The measurement approach was positively validated for the case of a packed bed of [...] Read more.

This paper provides the practical implementation of the single blow technique as an effective approach of average convective heat transfer coefficient measurement for a packed bed of horticultural products. The measurement approach was positively validated for the case of a packed bed of balls. The presented results cover heat transfer coefficient results for carrots stored in packed beds for two various arrangements (regular and irregular) and bed of apples under conditions of various turbulent intensity at the inlet to the bed. The turbulent intensity (defined as the ratio of the root mean square of the turbulent fluctuation of the air velocity to the mean air velocity) varied from 0.02 to 0.14. The applied velocity ranges for the tests refers to the conventional storage conditions. The heat transfer correlations were proposed based on the obtained results for each arrangement. It was demonstrated that due to flow laminarization inside the bed, the turbulence intensity has no significant effect on heat transfer inside the bed. Heat transfer enhancement of up to 25% was demonstrated for the case of the irregular carrot arrangement in the tested bed. The flow resistance correlations were additionally proposed for the tested beds. It was demonstrated that the product arrangement does not produce an important effect on the pressure drop. Full article

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30 pages, 9939 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Applicability of Constitutive Models to Describing the Compressibility of Mining Backfill: A Comparative Study

by Ruofan Wang, Feitao Zeng and Li Li

Processes 2021, 9(12), 2139; https://doi.org/10.3390/pr9122139 - 26 Nov 2021

Cited by 7 | Viewed by 2815

Abstract

The compressibility of mining backfill governs its resistance to the closure of surrounding rock mass, which should be well reflected in numerical modeling. In most numerical simulations of backfill, the Mohr–Coulomb elasto-plastic model is used, but is constantly criticized for its poor representativeness [...] Read more.

The compressibility of mining backfill governs its resistance to the closure of surrounding rock mass, which should be well reflected in numerical modeling. In most numerical simulations of backfill, the Mohr–Coulomb elasto-plastic model is used, but is constantly criticized for its poor representativeness to the mechanical response of geomaterials. Finding an appropriate constitutive model to better represent the compressibility of mining backfill is critical and necessary. In this paper, Mohr–Coulomb elasto-plastic model, double-yield model, and Soft Soil model are briefly recalled. Their applicability to describing the backfill compressibility is then assessed by comparing numerical and experimental results of one-dimensional consolidation and consolidated drained triaxial compression tests made on lowly cemented backfills available in the literature. The comparisons show that the Soft Soil model can be used to properly describe the experimental results while the application of the Mohr–Coulomb model and double-yield model shows poor description on the compressibility of the backfill submitted to large and cycle loading. A further application of the Soft Soil model to the case of a backfilled stope overlying a sill mat shows stress distributions close to those obtained by applying the Mohr–Coulomb model when rock wall closure is absent. After excavating the underlying stope, rock wall closure is generated and exercises compression on the overlying backfill. Compared to the results obtained by applying the Soft Soil model, an application of the Mohr–Coulomb model tends to overestimate the stresses in the backfill when the mine depth is small and underestimate the stresses when the mine depth is large due to the poor description of fill compressibility. The Soft Soil model is recommended to describe the compressibility of uncemented or lightly cemented backfill with small cohesions under external compressions associated with rock wall closure. Full article

(This article belongs to the Special Issue Numerical Modeling in Civil and Mining Geotechnical Engineering)

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31 pages, 22815 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Development of a General PAT Strategy for Online Monitoring of Complex Mixtures—On the Example of Natural Product Extracts from Bearberry Leaf (Arctostaphylos uva-ursi)

by Christoph Jensch, Larissa Knierim, Martin Tegtmeier and Jochen Strube

Processes 2021, 9(12), 2129; https://doi.org/10.3390/pr9122129 - 25 Nov 2021

Cited by 9 | Viewed by 3011

Abstract

For the first time, a universally applicable and methodical approach from characterization to a PAT concept for complex mixtures is conducted—exemplified on natural products extraction processes. Bearberry leaf (Arctostaphylos uva-ursi) extract is chosen as an example of a typical complex mixture [...] Read more.

For the first time, a universally applicable and methodical approach from characterization to a PAT concept for complex mixtures is conducted—exemplified on natural products extraction processes. Bearberry leaf (Arctostaphylos uva-ursi) extract is chosen as an example of a typical complex mixture of natural plant origin and generalizable in its composition. Within the quality by design (QbD) based process development the development and implementation of a concept for process analytical technology (PAT), a key enabling technology, is the next necessary step in risk and quality-based process development and operation. To obtain and provide an overview of the broad field of PAT, the development process is shown on the example of a complex multi-component plant extract. This study researches the potential of different process analytical technologies for online monitoring of different component groups and classifies their possible applications within the framework of a QbD-based process. Offline and online analytics are established on the basis of two extraction runs. Based on this data set, PLS models are created for the spectral data, and correlations are conducted for univariate data. In a third run, the prediction potential is researched. Conclusively, the results of this study are arranged in the concept of a holistic quality and risk-based process design and operation concept. Full article

(This article belongs to the Special Issue Towards Autonomous Operation of Biologics and Botanicals)

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18 pages, 5095 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Zn–Al Layered Double Hydroxides Synthesized on Aluminum Foams for Fluoride Removal from Water

by Yuliu Li, Riccardo Narducci, Alessandra Varone, Saulius Kaciulis, Eleonora Bolli and Roberto Pizzoferrato

Processes 2021, 9(12), 2109; https://doi.org/10.3390/pr9122109 - 24 Nov 2021

Cited by 8 | Viewed by 2939

Abstract

Fluoride excess in water represents an environmental issue and a risk for human health since it can cause several diseases, such as fluorosis, osteoporosis, and damage of the nervous system. Layered double hydroxides (LDHs) can be exploited to remove this contaminant from water [...] Read more.

Fluoride excess in water represents an environmental issue and a risk for human health since it can cause several diseases, such as fluorosis, osteoporosis, and damage of the nervous system. Layered double hydroxides (LDHs) can be exploited to remove this contaminant from water by taking advantage of their high ion-exchange capability. LDHs are generally mixed with polluted water in the form of powders, which then cause the problem of uneasy separation of the contaminated LDH sludge from the purified liquid. In this work, Zn–Al LDH films were directly grown in situ on aluminum foams that acted both as the reactant and substrate. This method enabled the removal of fluoride ions by simple immersion, with ensuing withdrawal of the foam from the de-contaminated water. Different LDH synthesis methods and aluminum foam types were investigated to improve the adsorption process. The contact time, initial fluoride concentration, adsorbent dosage, and pH were studied as the parameters that affect the fluoride adsorption capacity and efficiency. The highest absorption efficiency of approximately 70% was obtained by using two separate growth methods after four hours, and it effectively reduced the fluoride concentration from 3 mg/L to 1.1 mg/L, which is below the threshold value set by WHO for drinking water. Full article

(This article belongs to the Section Materials Processes)

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12 pages, 4591 KiB

Open AccessEditor’s ChoiceArticle

Optimalization of Design Parameters of Experimental Installation Concerning Preparation of Liquid Feed Mixtures

by Pavel Solonscikov, Jan Barwicki, Peter Savinyh and Marek Gaworski

Processes 2021, 9(12), 2104; https://doi.org/10.3390/pr9122104 - 23 Nov 2021

Cited by 2 | Viewed by 1444

Abstract

The article describes the initial conditions for the development of universal mechanization means for the process of mixing dry and liquid components. The essence of the method is to study the motion of a particle with different constructive and physical properties of the [...] Read more.

The article describes the initial conditions for the development of universal mechanization means for the process of mixing dry and liquid components. The essence of the method is to study the motion of a particle with different constructive and physical properties of the medium. The mathematical model of particle motion is based on theoretical mechanics and hydraulics. In this case, the main purpose of the study is to find the optimal design parameters for the installation. At the beginning, a theoretical analysis of the installation was carried out using the methods of classical mechanics and hydraulics. Experimental studies were carried out in several stages. At the beginning, one-factor experiments were conducted, followed by allocating the main factors and determining their interaction. Then, using the methods of planning the experiment, we obtained the regression equations and further optimized the parameters to summarize the main findings of the article. Modern installations should have versatility in any technological line; for example, an installation is presented that can not only mix, but further transport the mixture like a conventional pump, while providing a dosing device that is necessary for the feeding of dry components. Theoretical studies have been carried out in which the design of the impeller is substantiated at various speeds. Experimental studies to determine the design parameters of the installation are in continuous operation. The degree of homogeneity was Θ = 74%, with β2 = 80 … 100° and βst = 65 … 102°, while the value of the consumption of electrical energy is equal to Eel = 0.265 … 0.28 kWh/t. Full article

(This article belongs to the Section Process Control and Monitoring)

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19 pages, 2881 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Biodesulfurization of Dibenzothiophene and Its Alkylated Derivatives in a Two-Phase Bubble Column Bioreactor by Resting Cells of Rhodococcus erythropolis IGTS8

by George Prasoulas, Konstantinos Dimos, Panayiotis Glekas, Styliani Kalantzi, Stamatis Sarris, Chrysovalantis Templis, Konstantinos Vavitsas, Dimitris G. Hatzinikolaou, Nikolaos Papayannakos, Dimitris Kekos and Diomi Mamma

Processes 2021, 9(11), 2064; https://doi.org/10.3390/pr9112064 - 18 Nov 2021

Cited by 8 | Viewed by 3880

Abstract

Biodesulfurization (BDS) is considered a complementary technology to the traditional hydrodesulfurization treatment for the removal of recalcitrant sulfur compounds from petroleum products. BDS was investigated in a bubble column bioreactor using two-phase media. The effects of various process parameters, such as biocatalyst age [...] Read more.

Biodesulfurization (BDS) is considered a complementary technology to the traditional hydrodesulfurization treatment for the removal of recalcitrant sulfur compounds from petroleum products. BDS was investigated in a bubble column bioreactor using two-phase media. The effects of various process parameters, such as biocatalyst age and concentration, organic fraction percentage (OFP), and type of sulfur compound—namely, dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), and 4,6-diethyldibenzothiophene (4,6-DEDBT)—were evaluated, using resting cells of Rhodococcus erythropolis IGTS8. Cells derived from the beginning of the exponential growth phase of the bacterium exhibited the highest biodesulfurization efficiency and rate. The biocatalyst performed better in an OFP of 50% v/v. The extent of DBT desulfurization was dependent on cell concentration, with the desulfurization rate reaching its maximum at intermediate cell concentrations. A new semi-empirical model for the biphasic BDS was developed, based on the overall Michaelis-Menten kinetics and taking into consideration the deactivation of the biocatalyst over time, as well as the underlying mass transfer phenomena. The model fitted experimental data on DBT consumption and 2-hydroxibyphenyl (2-HBP) accumulation in the organic phase for various initial DBT concentrations and different organosulfur compounds. For constant OFP and biocatalyst concentration, the most important parameter that affects BDS efficiency seems to be biocatalyst deactivation, while the phenomenon is controlled by the affinities of biodesulfurizing enzymes for the different organosulfur compounds. Thus, desulfurization efficiency decreased with increasing initial DBT concentration, and in inverse proportion to increases in the carbon number of alkyl substituent groups. Full article

(This article belongs to the Section Biological Processes and Systems)

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