Processes

22 pages, 9489 KiB

Open AccessEditor’s ChoiceArticle

Digital Twin for HIV-Gag VLP Production in HEK293 Cells

by Alina Hengelbrock, Heribert Helgers, Axel Schmidt, Florian Lukas Vetter, Alex Juckers, Jamila Franca Rosengarten, Jörn Stitz and Jochen Strube

Processes 2022, 10(5), 866; https://doi.org/10.3390/pr10050866 - 27 Apr 2022

Cited by 22 | Viewed by 2880

Abstract

The development and adoption of digital twins (DT) for Quality-by-Design (QbD)-based processes with flexible operating points within a proven acceptable range (PAR) and automation through Advanced Process Control (APC) with Process Analytical Technology (PAT) instead of conventional process execution based on offline analytics [...] Read more.

The development and adoption of digital twins (DT) for Quality-by-Design (QbD)-based processes with flexible operating points within a proven acceptable range (PAR) and automation through Advanced Process Control (APC) with Process Analytical Technology (PAT) instead of conventional process execution based on offline analytics and inflexible process set points is one of the great challenges in modern biotechnology. Virus-like particles (VLPs) are part of a line of innovative drug substances (DS). VLPs, especially those based on human immunodeficiency virus (HIV), HIV-1 Gag VLPs, have very high potential as a versatile vaccination platform, allowing for pseudotyping with heterologous envelope proteins, e.g., the S protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As enveloped VLPs, optimal process control with minimal hold times is essential. This study demonstrates, for the first time, the use of a digital twin for the overall production process of HIV-1 Gag VLPs from cultivation, clarification, and purification to lyophilization. The accuracy of the digital twins is in the range of 0.8 to 1.4% in depth filtration (DF) and 4.6 to 5.2% in ultrafiltration/diafiltration (UFDF). The uncertainty due to variability in the model parameter determination is less than 4.5% (DF) and less than 3.8% (UFDF). In the DF, a prediction of the final filter capacity was demonstrated from as low as 5.8% (9mbar) of the final transmembrane pressure (TMP). The scale-up based on DT in chromatography shows optimization potential in productivity up to a factor of 2. The schedule based on DT and PAT for APC has been compared to conventional process control, and hold-time and process duration reductions by a factor of 2 have been achieved. This work lays the foundation for the short-term validation of the DT and PAT for APC in an automated S7 process environment and the conversion from batch to continuous production. Full article

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

► Show Figures

Figure 1

22 pages, 3360 KiB

Open AccessEditor’s ChoiceArticle

Large-Scale Production of Size-Adjusted β-Cell Spheroids in a Fully Controlled Stirred-Tank Reactor

by Florian Petry and Denise Salzig

Processes 2022, 10(5), 861; https://doi.org/10.3390/pr10050861 - 27 Apr 2022

Cited by 8 | Viewed by 2819

Abstract

For β-cell replacement therapies, one challenge is the manufacturing of enough β-cells (Edmonton protocol for islet transplantation requires 0.5–1 × 10⁶ islet equivalents). To maintain their functionality, β-cells should be manufactured as 3D constructs, known as spheroids. In this study, we investigated [...] Read more.

For β-cell replacement therapies, one challenge is the manufacturing of enough β-cells (Edmonton protocol for islet transplantation requires 0.5–1 × 10⁶ islet equivalents). To maintain their functionality, β-cells should be manufactured as 3D constructs, known as spheroids. In this study, we investigated whether β-cell spheroid manufacturing can be addressed by a stirred-tank bioreactor (STR) process. STRs are fully controlled bioreactor systems, which allow the establishment of robust, larger-scale manufacturing processes. Using the INS-1 β-cell line as a model for process development, we investigated the dynamic agglomeration of β-cells to determine minimal seeding densities, spheroid strength, and the influence of turbulent shear stress. We established a correlation to exploit shear forces within the turbulent flow regime, in order to generate spheroids of a defined size, and to predict the spheroid size in an STR by using the determined spheroid strength. Finally, we transferred the dynamic agglomeration process from shaking flasks to a fully controlled and monitored STR, and tested the influence of three different stirrer types on spheroid formation. We achieved the shear stress-guided production of up to 22 × 10⁶ ± 2 × 10⁶ viable and functional β-cell spheroids per liter of culture medium, which is sufficient for β-cell therapy applications. Full article

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

► Show Figures

Figure 1

26 pages, 18091 KiB

Open AccessEditor’s ChoiceArticle

Machine Learning to Estimate the Mass-Diffusion Distance from a Point Source under Turbulent Conditions

by Takahiro Ishigami, Motoki Irikura and Takahiro Tsukahara

Processes 2022, 10(5), 860; https://doi.org/10.3390/pr10050860 - 26 Apr 2022

Cited by 5 | Viewed by 2265

Abstract

Technologies that predict the sources of substances diffused in the atmosphere, ocean, and chemical plants are being researched in various fields. The flows transporting such substances are typically in turbulent states, and several problems including the nonlinearity of turbulence must be overcome to [...] Read more.

Technologies that predict the sources of substances diffused in the atmosphere, ocean, and chemical plants are being researched in various fields. The flows transporting such substances are typically in turbulent states, and several problems including the nonlinearity of turbulence must be overcome to enable accurate estimations of diffusion-source location from limited observation data. We studied the feasibility of machine learning, specifically convolutional neural networks (CNNs), to the problem of estimating the diffusion distance from a point source, based on two-dimensional, instantaneous information of diffused-substance distributions downstream of the source. The input image data for the learner are the concentration (or luminance of fluorescent dye) distributions affected by turbulent motions of the transport medium. In order to verify our approach, we employed experimental data of a fully developed turbulent channel flow with a dye nozzle, wherein we attempted to estimate the distances between the dye nozzle and downstream observation windows. The inference accuracy of four different CNN architectures were investigated, and some achieved an accuracy of more than 90%. We confirmed the independence of the inference accuracy on the anisotropy (or rotation) of the image. The trained CNN can recognize the turbulent characteristics for estimating the diffusion source distance without statistical processing. The learners have a strong dependency on the condition of learning images, such as window size and image noise, implying that learning images should be carefully handled for obtaining higher generalization performance. Full article

(This article belongs to the Special Issue Advances in Statistical Description of Scalar Turbulence)

► Show Figures

Figure 1

22 pages, 2750 KiB

Open AccessEditor’s ChoiceArticle

Technical and Economical Assessment of CO₂ Capture-Based Ammonia Aqueous

by Nela Slavu, Adrian Badea and Cristian Dinca

Processes 2022, 10(5), 859; https://doi.org/10.3390/pr10050859 - 26 Apr 2022

Cited by 10 | Viewed by 2543

Abstract

In the context of climate change and the reduction in CO₂ emissions from fossil fuel combustion, the integration of CO₂ capture technologies in steam power plants is a key solution. The aim of this study was to analyze the use of [...] Read more.

In the context of climate change and the reduction in CO₂ emissions from fossil fuel combustion, the integration of CO₂ capture technologies in steam power plants is a key solution. The aim of this study was to analyze the use of ammonia, at different mass concentrations, in capturing post-combustion CO₂ in a coal-fired power station and comparing it with the reference 30% MEA case. In this regard, a multi-criteria model was developed to establish the optimal solvent used, considering the least impact on technical performance, economic, and environmental indicators. As a result, the lowest CO₂ capture cost was obtained for the CO₂ capture process based on 7% NH₃, with 59.07 €/tCO₂. Integration of the CO₂ capture process is more economically viable when the CO₂ emissions tax is higher than 70 €/tCO₂ for 7% NH₃ and 15% NH₃, 80 €/tCO₂ for 5% NH₃ and 30% MEA, and 90 €/tCO₂ for 2% NH₃. Regarding the overall efficiency, the energy penalty associated with the CO₂ capture process integration varied between 15 and 35%, and the lowest value was obtained for 15% NH₃. The GWP indicator ranged between 113 and 149 kg_CO₂_eq/MWh for NH₃ compared to MEA 133 kg_CO₂_eq/MWh and the case with no CO₂ capture was 823 kg_CO₂_eq/MWh. Full article

(This article belongs to the Special Issue Advances in Deep Eutectic Solvents: New Green Solvents)

► Show Figures

Figure 1

18 pages, 2683 KiB

Open AccessEditor’s ChoiceArticle

A Lean Manufacturing Progress Model and Implementation for SMEs in the Metal Products Industry

by Chien-Yi Huang, Dasheng Lee, Shu-Chuan Chen and William Tang

Processes 2022, 10(5), 835; https://doi.org/10.3390/pr10050835 - 24 Apr 2022

Cited by 11 | Viewed by 10658

Abstract

The manufacturing industry faces the challenge of small and diversified customer orders. To meet this challenge, strong internal production capabilities are required. A lean manufacturing process that uses fewer resources and offers greater process improvement will help SMEs to continue to contribute to [...] Read more.

The manufacturing industry faces the challenge of small and diversified customer orders. To meet this challenge, strong internal production capabilities are required. A lean manufacturing process that uses fewer resources and offers greater process improvement will help SMEs to continue to contribute to the global economy. Though SMEs provide most employment opportunities, previous studies have focused on large companies in auto-manufacturing-related industries. With the commitment and support of the management, and the application of a value stream map (VSM) and related improvement tools, we produced a practical process improvement model for a lean manufacturing system in an SME. With the commitment and support of the management and the joint efforts of the project improvement staff, the 10 improvement projects over a six-month period all achieved their goals: reduction in lead time from 26 days to 19.5 days, improvement of welding per people per hour (PPH) efficiency by 28.3%, improvement of packaging PPH efficiency by 64.1%, improvement of working in process (WIP) efficiency at the production site by 83.84%, and improvement of raw material storage by 83.84%. The efficiency of the raw material warehouse inventory was improved by 58.63%, and the efficiency of the shipment completion rate was improved by 14.5%. Full article

(This article belongs to the Special Issue Sustainable Production Scheduling and Supply Chain Management under Resource Constraints and Factory Eligibility)

► Show Figures

Figure 1

36 pages, 1500 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Bio-Refinery of Oilseeds: Oil Extraction, Secondary Metabolites Separation towards Protein Meal Valorisation—A Review

by Mohamad Nehmeh, Ivonne Rodriguez-Donis, Alexandre Cavaco-Soares, Philippe Evon, Vincent Gerbaud and Sophie Thiebaud-Roux

Processes 2022, 10(5), 841; https://doi.org/10.3390/pr10050841 - 24 Apr 2022

Cited by 20 | Viewed by 7499

Abstract

Edible oil extraction is a large and well-developed sector based on solvent assisted extraction using volatile organic compounds such as hexane. The extraction of oil from oilseeds generates large volumes of oilseed by-products rich in proteins, fibres, minerals and secondary metabolites that can [...] Read more.

Edible oil extraction is a large and well-developed sector based on solvent assisted extraction using volatile organic compounds such as hexane. The extraction of oil from oilseeds generates large volumes of oilseed by-products rich in proteins, fibres, minerals and secondary metabolites that can be valued. This work reviews the current status and the bio-macro-composition of oilseeds, namely soybean, rapeseed, sunflower and flaxseed, and the refining process, comprising the extraction of oil, the valorisation and separation of valuable secondary metabolites such as phenolic compounds, and the removal of anti-nutritional factors such as glucosinolates, while retaining the protein in the oilseed meal. It also provides an overview of alternative solvents and some of the unconventional processes used as a replacement to the conventional extraction of edible oil, as well as the solvents used for the extraction of secondary metabolites and anti-nutritional factors. These biologically active compounds, including oils, are primordial raw materials for several industries such as food, pharmaceutical or cosmetics. Full article

(This article belongs to the Special Issue Advanced Technologies for Vegetable Oil Extraction)

► Show Figures

Figure 1

10 pages, 1465 KiB

Open AccessEditor’s ChoiceArticle

Feasibility of a Complex Optimized Process for the Treatment of Patients Receiving Hip and Knee Endoprostheses in Most Different Settings in Germany—Results from the PROMISE Trial

by Ulrich Betz, Laura Langanki, Florian Heid, Lukas Schollenberger, Kai Kronfeld, Matthias Büttner, Britta Büchler, Lukas Eckhard, Thomas Klonschinski and Philipp Drees

Processes 2022, 10(5), 824; https://doi.org/10.3390/pr10050824 - 22 Apr 2022

Cited by 1 | Viewed by 1443

Abstract

Background: While there is evidence on the effectiveness of optimized treatment processes for patients receiving hip and knee endoprostheses, feasibility in various settings has not been adequately investigated. The multicenter PROMISE Trial (Process optimization by interdisciplinary and cross-sectoral care using the example of [...] Read more.

Background: While there is evidence on the effectiveness of optimized treatment processes for patients receiving hip and knee endoprostheses, feasibility in various settings has not been adequately investigated. The multicenter PROMISE Trial (Process optimization by interdisciplinary and cross-sectoral care using the example of patients with hip and knee prostheses) was set up to fill this gap. Methods: A complex optimized process was implemented in three German hospitals offering different levels of care and five cooperating rehabilitation centers. For the feasibility question, data on 19 parameters characterizing the defined process were collected. The extent of cross-sectoral collaboration was a special focus. Results: The data show, for almost all parameters in all facilities, an implementation rate of more than 80% with missing data below 5%, n = 1887 study participants. A total of 96.8% attended a rehabilitation program, and for 29.2% rehabilitation took place in a PROMISE-collaborating facility. Conclusions: Adherence to the defined and well-documented process was very high in all three organizationally very different hospitals, so that feasibility is given and transferability of the concept can be assumed. An exception was the targeted integration of rehabilitation into the treatment process. The goal of cross-sectoral networking could only be partially achieved. Full article

► Show Figures

Figure 1

19 pages, 3482 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Recovery of Mineral Wool Waste and Recycled Aggregates for Use in the Manufacturing Processes of Masonry Mortars

by Daniel Ferrández, Manuel Álvarez, Pablo Saiz and Alicia Zaragoza-Benzal

Processes 2022, 10(5), 830; https://doi.org/10.3390/pr10050830 - 22 Apr 2022

Cited by 4 | Viewed by 1840

Abstract

The environmental problems caused by industrial waste are of a universal nature. In this sense, achieving an adequate management of construction and demolition waste has become one of the great challenges of today’s society. This work studies the possibility of recovering mineral wool [...] Read more.

The environmental problems caused by industrial waste are of a universal nature. In this sense, achieving an adequate management of construction and demolition waste has become one of the great challenges of today’s society. This work studies the possibility of recovering mineral wool thermal insulation waste for its reincorporation into the manufacturing process of masonry mortar. To this end, an experimental campaign has been conducted with mortars made with natural aggregate and two types of recycled aggregates: concrete and mixed ceramic, in which mineral wool fibers are incorporated as a partial replacement of sand in percentages of 0%, 10% and 20%. The results show that, although the traditional mortars offer better technical performance, the mortars made with recycled aggregate present adequate viability for use on-site. Furthermore, it has been concluded that the incorporation of recycled mineral wool fibers in the mortar matrix decreases the thermal conductivity and shrinkage during the setting of these materials, increasing their mechanical flexural strength and durability. Full article

(This article belongs to the Special Issue Design for Sustainable Behaviour: Resource Efficiency and Valuable Waste Recovery)

► Show Figures

Figure 1

15 pages, 16124 KiB

Open AccessEditor’s ChoiceArticle

Shear Strength of Adhesive Bonding of Plastics Intended for High Temperature Plastic Radiators

by Ilya Astrouski, Tereza Kudelova, Josef Kalivoda and Miroslav Raudensky

Processes 2022, 10(5), 806; https://doi.org/10.3390/pr10050806 - 20 Apr 2022

Cited by 4 | Viewed by 4787

Abstract

The use of adhesive joints has increased in recent decades due to their competitive features in comparison with other joining methods. They can be used in specific applications where there is no possibility to use alternative connection techniques. Adhesive bonding was used to [...] Read more.

The use of adhesive joints has increased in recent decades due to their competitive features in comparison with other joining methods. They can be used in specific applications where there is no possibility to use alternative connection techniques. Adhesive bonding was used to assemble the prototype of a high-temperature car radiator (operated up to 125 °C) with a total of 12,240 plastic tubes. This work aims to estimate the shear strength of different adhesives intended for bonding the plastics used to assemble the above-mentioned high-temperature radiator. Fourteen commercial adhesives were tested with one thermoset plastic (G11 glass fabric epoxy sheets) and two glass-reinforced thermoplastics (polyamide PA66-GF30 and polyphenylene sulfide PPS-GF40). Tests were conducted according EN 1465 to determine tensile lap-shear strength of bonding. Testing showed that only 4 of the 14 adhesives tested exhibit substantial bonding strength at temperatures above 120 °C and only one is resistant at 180 °C. The AS60/AW60 adhesive showed the best results for all three substrates: 1.6 MPa for epoxy sheets and PA66-GF, and 1.4 MPa for PPS-GF40. Additionally, the influence of the surface treatment with cold plasma was evaluated on a clean and activated bonding surface, causing a 30% increase in the shear strength. Full article

(This article belongs to the Special Issue New Advances in Heat Transfer and Fluid Flow)

► Show Figures

Figure 1

16 pages, 10283 KiB

Open AccessEditor’s ChoiceArticle

Interpretation of Chemical Analyses and Cement Modules in Flysch by (Geo)Statistical Methods, Example from the Southern Croatia

by Nikolina Bralić and Tomislav Malvić

Processes 2022, 10(5), 813; https://doi.org/10.3390/pr10050813 - 20 Apr 2022

Cited by 1 | Viewed by 1578

Abstract

This study included the testing of normal (Gaussian) distribution of input data and, consequently, spatially interpolating maps of chemical components and cement modules in the flysch. This deposit contains the raw material for cement production. The researched area is located in southern Croatia, [...] Read more.

This study included the testing of normal (Gaussian) distribution of input data and, consequently, spatially interpolating maps of chemical components and cement modules in the flysch. This deposit contains the raw material for cement production. The researched area is located in southern Croatia, near Split, as part of the exploited field “St. Juraj–St. Kajo”. There are six lithological units: (1) alternation of marls and sandstones with inclusions of conglomerates, (2) marl, (3) calcsiltite, (4) calcarenite, (5) marl with nummulites, (6) debrites, and (7) clayey marl. All of them are deposited in the (a) northern and (b) southern beds. Only debrites are divided into the (a) western and (b) eastern layers. Those lithological units were divided technologically based on their cement modules (lime saturation factor (LSF), silicate module (SM), and aluminate module (AM)). The average thicknesses were analysed, followed by normality tests (Kolmogorov–Smirnov (K–S) and Shapiro–Wilk (S–W)) of the chemical analyses: CaO, SiO₂, Al₂O₃, Fe₂O₃, MgO, SO₃, Na₂O, K₂O, CaCO₃ (%) and three cement modules (LSF, SM, AM), available in the six lithological units. The normality tests were applied based on a number of input data. The further interpolation was performed using two methods, kriging and inverse distance weighting, mapping CaO (%), SiO₂ (%), and LSF (−) in three different lithological units. The interpolation methods were selected based on two criteria: (a) normality test pass or fail and (b) the amount of data. In total, 144 tests were calculated, including sets from 7 to 36 points. The results show the current situation in the quarry, after decades of production, making reliable the future predictions of cement raw material exploitation. Full article

► Show Figures

Figure 1

19 pages, 4573 KiB

Open AccessEditor’s ChoiceArticle

Digital Twins for scFv Production in Escherichia coli

by Heribert Helgers, Alina Hengelbrock, Axel Schmidt, Florian Lukas Vetter, Alex Juckers and Jochen Strube

Processes 2022, 10(5), 809; https://doi.org/10.3390/pr10050809 - 20 Apr 2022

Cited by 16 | Viewed by 2492

Abstract

Quality-by-Design (QbD) is demanded by regulatory authorities in biopharmaceutical production. Within the QbD frame advanced process control (APC), facilitated through process analytical technology (PAT) and digital twins (DT), plays an increasingly important role as it can help to assure to stay within the [...] Read more.

Quality-by-Design (QbD) is demanded by regulatory authorities in biopharmaceutical production. Within the QbD frame advanced process control (APC), facilitated through process analytical technology (PAT) and digital twins (DT), plays an increasingly important role as it can help to assure to stay within the predefined proven acceptable range (PAR).This ensures high product quality, minimizes failure and is an important step towards a real-time-release testing (RTRT) that could help to accelerate time-to-market of drug substances, which is becoming even more important in light of dynamical pandemic situations. The approach is exemplified on scFv manufacturing in Escherichia coli. Simulation results from digital twins are compared to experimental data and found to be accurate and precise. Harvest is achieved by tangential flow filtration followed by product release through high pressure homogenization and subsequent clarification by tangential flow filtration. Digital twins of the membrane processes show that shear rate and transmembrane pressure are significant process parameters, which is in line with experimental data. Optimized settings were applied to 0.3 bar and a shear rate of 11,000 s⁻¹. Productivity of chromatography steps were 5.3 g/L/d (Protein L) and 2167 g/L/d (CEX) and the final product concentration was 8 g/L. Based on digital twin results, an optimized process schedule was developed that decreased purification time to one working day, which is a factor-two reduction compared to the conventional process schedule. This work presents the basis for future studies on advanced process control and automation for biologics production in microbials in regulated industries. Full article

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

► Show Figures

Figure 1

16 pages, 3764 KiB

Open AccessEditor’s ChoiceArticle

Study of Gas-to-Liquid Heat Pipe Heat Exchanger

by Pratik Prakash Gupta, Sundararaj Senthilkumar and Shung-Wen Kang

Processes 2022, 10(5), 808; https://doi.org/10.3390/pr10050808 - 20 Apr 2022

Cited by 1 | Viewed by 3049

Abstract

This study is focused on the study and development of a gas-to-liquid heat pipe heat exchanger (HPHE) based on numerical and experimental analysis. Stainless steel heat pipes were installed inside the heat exchanger in the form of three equilateral triangles, staggered into a [...] Read more.

This study is focused on the study and development of a gas-to-liquid heat pipe heat exchanger (HPHE) based on numerical and experimental analysis. Stainless steel heat pipes were installed inside the heat exchanger in the form of three equilateral triangles, staggered into a hexagonal configuration to simulate the waste heat recovery from hot exhaust gas to a water flow. The first main aim of this study was focused on 3D design and numerical analysis, which were used to create and calculate the effect of similar input conditions on the overall system. The system was tested for the overall heat transfer by measuring the temperature change in both fluids. The heat transfer and overall average temperature were used to calculate the effectiveness of the system. In the second part of this study, a test of the waste heat recovery was undertaken with this setup, using water as the cooling fluid. The study was conducted with different input velocities and temperatures of waste hot air, controlled simultaneously by the input fan and air heater, whereas the cooling water was kept at a steady state of 30 °C and 0.0156 kg/s at the input. The hot air velocity was controlled by fans with different inlet air velocities of 0.3 m/s, 0.5 m/s, and 0.7 m/s. Moreover, the temperature of the air was changed from 150 °C to 250 °C with a step of 25 °C. The increase in temperature and the velocity of air was directly proportional to the amount of heat transferred from the air to the cooling water, and the effectiveness was also found to be inversely proportional to both of the varying input parameters. The numerical study showed a maximum increase of 12% in the heat transfer. The output temperatures of hot and cold fluids showed maximum increases of 7 K and 3 K, respectively. The numerical system with such input parameters can be evaluated further to predict the behavior of changes in the design and parameters. Full article

(This article belongs to the Special Issue Emerging Technologies in Heating, Ventilation, Air Conditioning and Refrigeration (HVAC&R) Systems)

► Show Figures

Figure 1

13 pages, 1136 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Innovative Food Packaging, Food Quality and Safety, and Consumer Perspectives

by Mary R. Yan, Sally Hsieh and Norberto Ricacho

Processes 2022, 10(4), 747; https://doi.org/10.3390/pr10040747 - 12 Apr 2022

Cited by 51 | Viewed by 17898

Abstract

Packaging is an integral part of the food industry associated with food quality and safety including food shelf life, and communications from the marketing perspective. Traditional food packaging provides the protection of food from damage and storage of food products until being consumed. [...] Read more.

Packaging is an integral part of the food industry associated with food quality and safety including food shelf life, and communications from the marketing perspective. Traditional food packaging provides the protection of food from damage and storage of food products until being consumed. Packaging also presents branding and nutritional information and promotes marketing. Over the past decades, plastic films were employed as a barrier to keep food stuffs safe from heat, moisture, microorganisms, dust, and dirt particles. Recent advancements have incorporated additional functionalities in barrier films to enhance the shelf life of food, such as active packaging and intelligent packaging. In addition, consumer perception has influences on packaging materials and designs. The current trend of consumers pursuing environmental-friendly packaging is increased. With the progress of applied technologies in the food sector, sustainable packaging has been emerging in response to consumer preferences and environmental obligations. This paper reviews the importance of food packaging in relation to food quality and safety; the development and applications of advanced smart, active, and intelligent packaging systems, and the properties of an oxygen barrier. The advantages and disadvantages of these packaging are discussed. Consumer perceptions regarding environmental-friendly packaging that could be applied in the food industry are also discussed. Full article

(This article belongs to the Special Issue Advances in Food Processes Modeling)

► Show Figures

Figure 1

32 pages, 2116 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Recent Advances in the Decontamination and Upgrading of Waste Plastic Pyrolysis Products: An Overview

by Salma Belbessai, Abir Azara and Nicolas Abatzoglou

Processes 2022, 10(4), 733; https://doi.org/10.3390/pr10040733 - 11 Apr 2022

Cited by 32 | Viewed by 9607

Abstract

Extensive research on the production of energy and valuable materials from plastic waste using pyrolysis has been widely conducted during recent years. Succeeding in demonstrating the sustainability of this technology economically and technologically at an industrial scale is a great challenge. In most [...] Read more.

Extensive research on the production of energy and valuable materials from plastic waste using pyrolysis has been widely conducted during recent years. Succeeding in demonstrating the sustainability of this technology economically and technologically at an industrial scale is a great challenge. In most cases, crude pyrolysis products cannot be used directly for several reasons, including the presence of contaminants. This is confirmed by recent studies, using advanced characterization techniques such as two-dimensional gas chromatography. Thus, to overcome these limitations, post-treatment methods, such as dechlorination, distillation, catalytic upgrading and hydroprocessing, are required. Moreover, the integration of pyrolysis units into conventional refineries is only possible if the waste plastic is pre-treated, which involves sorting, washing and dehalogenation. The different studies examined in this review showed that the distillation of plastic pyrolysis oil allows the control of the carbon distribution of different fractions. The hydroprocessing of pyrolytic oil gives promising results in terms of reducing contaminants, such as chlorine, by one order of magnitude. Recent developments in plastic waste and pyrolysis product characterization methods are also reported in this review. The application of pyrolysis for energy generation or added-value material production determines the economic sustainability of the process. Full article

(This article belongs to the Topic Sustainable Energy Technology)

► Show Figures

Figure 1

15 pages, 5303 KiB

Open AccessEditor’s ChoiceReview

Mechanism of Particle Agglomeration for Single and Multi-Nozzle Atomization in Spray Drying: A Review

by Ireneusz Zbicinski, Krzysztof Ciesielski and Bangguo Ge

Processes 2022, 10(4), 727; https://doi.org/10.3390/pr10040727 - 9 Apr 2022

Cited by 9 | Viewed by 4403

Abstract

This paper reviews experimental works on the effects of single nozzle location and multi-nozzle atomization on the mechanism of particle agglomeration in spray drying. In addition to the naturally occurring primary agglomeration, forced and secondary agglomeration is observed as an effect of different [...] Read more.

This paper reviews experimental works on the effects of single nozzle location and multi-nozzle atomization on the mechanism of particle agglomeration in spray drying. In addition to the naturally occurring primary agglomeration, forced and secondary agglomeration is observed as an effect of different nozzle positions or multiple-nozzle atomization in spray drying. Particle size diameters in the spray drying process for atomization from a single nozzle located at the top of the tower are larger than at the bottom of the tower because of the lower ambient air temperatures and longer residence time in the agglomeration zone. The trend of reduction in particle size is observed in all analyzed works when the nozzle is moved down towards the air inlet, due to droplets’ exposure to higher air temperatures and shorter residence time in the drying chamber. Conditions of droplet–droplet, dry–dry or sticky–dry collisions leading to the development of coalescence, agglomeration and rebound zones for multiple-nozzle atomization are described and discussed. Typically, log normal PSD was found for single-nozzle spraying whereas for multi nozzle arrangement, bi-modal particle size distribution was found both for drying in lab and industrial scale. Full article

(This article belongs to the Special Issue Innovation in Chemical Plant Design)

► Show Figures

Figure 1

20 pages, 2487 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Improved Foods Using Enzymes from Basidiomycetes

by Ralf G. Berger and Franziska Ersoy

Processes 2022, 10(4), 726; https://doi.org/10.3390/pr10040726 - 9 Apr 2022

Cited by 4 | Viewed by 3504

Abstract

Within the kingdom of fungi, the division Basidiomycota represents more than 30,000 species, some with huge genomes indicating great metabolic potential. The fruiting bodies of many basidiomycetes are appreciated as food (“mushrooms”). Solid-state and submerged cultivation processes have been established for many species. [...] Read more.

Within the kingdom of fungi, the division Basidiomycota represents more than 30,000 species, some with huge genomes indicating great metabolic potential. The fruiting bodies of many basidiomycetes are appreciated as food (“mushrooms”). Solid-state and submerged cultivation processes have been established for many species. Specifically, xylophilic fungi secrete numerous enzymes but also form smaller metabolites along unique pathways; both groups of compounds may be of interest to the food processing industry. To stimulate further research and not aim at comprehensiveness in the broad field, this review describes some recent progress in fermentation processes and the knowledge of fungal genetics. Processes with potential for food applications based on lipases, esterases, glycosidases, peptidases and oxidoreductases are presented. The formation and degradation of colourants, the degradation of harmful food components, the formation of food ingredients and particularly of volatile and non-volatile flavours serve as examples. In summary, edible basidiomycetes are foods—and catalysts—for food applications and rich donors of genes to construct heterologous cell factories for fermentation processes. Options arise to support the worldwide trend toward greener, more eco-friendly and sustainable processes. Full article

(This article belongs to the Special Issue Advances in Microbial Fermentation Processes II)

► Show Figures

Figure 1

11 pages, 3307 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Adjusting the Structure of a Peptide Nucleic Acid (PNA) Molecular Beacon and Promoting Its DNA Detection by a Hybrid with Quencher-Modified DNA

by Hajime Shigeto, Takamasa Kishi, Koki Ishii, Takashi Ohtsuki, Shohei Yamamura and Mizuki Kitamatsu

Processes 2022, 10(4), 722; https://doi.org/10.3390/pr10040722 - 8 Apr 2022

Cited by 1 | Viewed by 2197

Abstract

In this study, we performed an elaborate adjustment of the structure of peptide nucleic acid (PNA) molecular beacons as probes for detecting nucleic acids. We synthesized the PNA beacons with various numbers of Glu, Lys, and dabcyl (Dab) quenchers in them, and we [...] Read more.

In this study, we performed an elaborate adjustment of the structure of peptide nucleic acid (PNA) molecular beacons as probes for detecting nucleic acids. We synthesized the PNA beacons with various numbers of Glu, Lys, and dabcyl (Dab) quenchers in them, and we investigated their fluorescence changes (F_1/1/F₀) with and without full-match DNA. As the numbers of Glu/Lys or Dab increased, the F_1/1/F₀ tended to decrease. Among the different beacons, the PNA beacon with one Glu and one Lys (P1Q1) showed the largest F_1/1/F₀. On the other hand, a relatively large F_1/1/F₀ was obtained when the number of Glu/Lys and the number of Dab were the same, and the balance between the numbers of Glu/Lys and Dab seemed to affect the F_1/1/F₀. We also investigated the DNA detection by the prehybrid of P1Q1, which consists of the T790M base sequence, [P1Q1(T790M)], with quencher-modified DNA (Q-DNA). We examined the DNA detection with single-base mismatch by P1Q1(T790M), and we clarified that there was difficulty in detecting the sequence with P1Q1 alone, but that the sequence was successfully detected by the prehybrid of P1Q1 with the Q-DNA. Full article

(This article belongs to the Special Issue The Amazing World of Peptide Engineering)

► Show Figures

Figure 1

21 pages, 4407 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Transfer of Potentially Toxic Elements in the Soil-Plant System in Magnesite Mining and Processing Areas

by Lenka Štofejová, Juraj Fazekaš and Danica Fazekašová

Processes 2022, 10(4), 720; https://doi.org/10.3390/pr10040720 - 8 Apr 2022

Cited by 4 | Viewed by 1672

Abstract

Mining activities, ore concentrations, and transport processes generate large amounts of pollutants, including hazardous elements, which are released into the environment. This work presents the results of experimental research aimed at evaluating the environmental risks of soil and plant contamination in two magnesite [...] Read more.

Mining activities, ore concentrations, and transport processes generate large amounts of pollutants, including hazardous elements, which are released into the environment. This work presents the results of experimental research aimed at evaluating the environmental risks of soil and plant contamination in two magnesite mining and processing areas in the Slovak Republic, and assesses the phytoremediation potential of dominant plant species. Eleven potentially toxic elements in the soil were investigated using X-ray fluorescence spectrometry (Cd, Pb, Cr, Zn, Cu, As, Ni, Mn, Mg, Fe) and atomic absorption spectrometry (Hg). In plants, potentially toxic elements were investigated using inductively coupled plasma mass spectrometry (Cu, As, Cd, Pb) and inductively coupled plasma atomic emission spectrometry (Cr, Zn, Mn, Mg). Selected soil parameters (pH, redox potential, and soil organic matter) were also investigated. Soil contamination was evaluated using environmental indices (geoaccumulation index—I_geo, enrichment factor—EF, contamination factor—C_f, degree of contamination—C_d). The phytoremediation potential of plants was evaluated using the bioconcentration factor (BCF) and the translocation factor (TF). The soil reaction in the studied areas indicated a strong alkalization of the soil. The soils in Jelšava-Lubeník were significantly contaminated with Cr, As, Mn, and Mg. The most significant enrichment based on the average values of EF was found to be in the order of Cd > Mg > Zn > Cu > As > Cr > Ni > Pb > Fe > Hg > Mn. The observed values of C_f and C_d indicated a high degree of soil contamination. In Košice, the soils were found to be significantly contaminated with Cr, Mn, Mg, and Ni. The most significant enrichment was found in the order of Cd > Mn > Ni > Pb > Zn > Mg > Cu > As > Fe > Cr > Hg. Very high C_f was found for Pb and Cr. The results of correlation and hierarchical cluster analyses suggest a similar origin of pollutants caused by significant anthropogenic interventions due to magnesite mining and processing. The investigated dominant plant species, Phragmites australis, Agrostis stolonifera, Elytrigia repens, and Taraxacum officinale are able to accumulate high concentrations of the monitored potentially toxic elements without more serious load or damage. The results of BCF and TF confirmed that P. australis and T. officinale appeared to be suitable accumulators in the phytoextraction process. In the case of E. repens and A. stolonifera it was confirmed that they accumulate and immobilize high concentrations of potentially toxic elements, especially in the roots, establishing the suitability of their use in phytostabilization processes. Full article

(This article belongs to the Special Issue Innovative Treatments for the Improvement of Bioremediation Processes)

► Show Figures

Figure 1

19 pages, 1890 KiB

Open AccessFeature PaperEditor’s ChoiceReview

A Review of Stand-Alone and Hybrid Microbial Electrochemical Systems for Antibiotics Removal from Wastewater

by Basem S. Zakaria and Bipro Ranjan Dhar

Processes 2022, 10(4), 714; https://doi.org/10.3390/pr10040714 - 7 Apr 2022

Cited by 7 | Viewed by 4083

Abstract

The growing concern about residual antibiotics in the water environment pushes for innovative and cost-effective technologies for antibiotics removal from wastewater. In this context, various microbial electrochemical systems have been investigated as an alternative to conventional wastewater technologies that are usually ineffective for [...] Read more.

The growing concern about residual antibiotics in the water environment pushes for innovative and cost-effective technologies for antibiotics removal from wastewater. In this context, various microbial electrochemical systems have been investigated as an alternative to conventional wastewater technologies that are usually ineffective for the adequate removal of antibiotics. This review article details the development of stand-alone and hybrid or integrated microbial electrochemical systems for antibiotics removal from wastewater. First, technical features, antibiotics removal efficiencies, process optimization, and technological bottlenecks of these systems are discussed. Second, a comparative summary based on the existing reports was established to provide insights into the selection between stand-alone and hybrid systems. Finally, research gaps, the relevance of recent progress in complementary areas, and future research needs have been discussed. Full article

(This article belongs to the Special Issue Emerging Technologies for Water and Wastewater Treatment)

► Show Figures

Graphical abstract

8 pages, 1464 KiB

Open AccessEditor’s ChoiceArticle

Need for a Next Generation of Chromatography Models—Academic Demands for Thermodynamic Consistency and Industrial Requirements in Everyday Project Work

by Florian Lukas Vetter and Jochen Strube

Processes 2022, 10(4), 715; https://doi.org/10.3390/pr10040715 - 7 Apr 2022

Cited by 3 | Viewed by 1905

Abstract

Process chromatography modelling for process development, design, and optimization as well as process control has been under development for decades. Still, the discussion of scientific potential and industrial applications needs is open to innovation. The discussion of next-generation modelling approaches starting from Langmuirian [...] Read more.

Process chromatography modelling for process development, design, and optimization as well as process control has been under development for decades. Still, the discussion of scientific potential and industrial applications needs is open to innovation. The discussion of next-generation modelling approaches starting from Langmuirian to steric mass action and multilayer or thermodynamic consistent real and ideal adsorption theory or colloidal particle adsorption approaches is continued. Full article

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

► Show Figures

Figure 1

26 pages, 9138 KiB

Open AccessEditor’s ChoiceArticle

A Machine Learning Approach for Phase-Split Calculations in n-Octane/Water and PASN/Water Systems

by Sandra Lopez-Zamora, Salvador Escobedo and Hugo de Lasa

Processes 2022, 10(4), 710; https://doi.org/10.3390/pr10040710 - 6 Apr 2022

Viewed by 2328

Abstract

Flash calculations, including phase split and phase classification for both n-octane/water blends and paraffinic aromatic synthetic naphtha (PASN)/water blends present significant computational challenges. Calculations to establish the two-phase and three-phase regions, as well as the transitions between regions, were addressed by a phase [...] Read more.

Flash calculations, including phase split and phase classification for both n-octane/water blends and paraffinic aromatic synthetic naphtha (PASN)/water blends present significant computational challenges. Calculations to establish the two-phase and three-phase regions, as well as the transitions between regions, were addressed by a phase classification method proposed in a recent contribution involving machine learning (ML). This work focusses on the phase-split calculations, considering (a) the lack of numerical convergence of the traditional calculations and their related numerical issues for water/n-octane and PASN/water systems based on the Rachford–Rice derived surfaces and (b) the successful implementation of an ML approach based on a K-nearest-neighbor (KNN) algorithm, which uses the abundant experimental data obtained in a CREC-VL cell. Full article

(This article belongs to the Special Issue Calculating Generalized Thermodynamic Equilibrium)

► Show Figures

Graphical abstract

23 pages, 1426 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Environmental Aspects of the Combined Cooling, Heating, and Power (CCHP) Systems: A Review

by Mohsen Salimi, Morteza Hosseinpour, Shabnam Mansouri and Tohid N.Borhani

Processes 2022, 10(4), 711; https://doi.org/10.3390/pr10040711 - 6 Apr 2022

Cited by 8 | Viewed by 3597

Abstract

Expanding cities means increasing the need for energy in the residential sector. The supply of this energy must be in environmentally friendly ways; one method of meeting demand in the residential sector is the use of combined cooling, heating, and power (CCHP) systems. [...] Read more.

Expanding cities means increasing the need for energy in the residential sector. The supply of this energy must be in environmentally friendly ways; one method of meeting demand in the residential sector is the use of combined cooling, heating, and power (CCHP) systems. The current review paper shows that due to the high cost of gas and electricity, CCHP can be used in various sectors, such as hospitals and airports, to reduce energy consumption with lower environmental impacts by using renewable energy systems as the main driver. While CCHP systems are not feasible in tropical regions with high cooling demand, a solar hybrid system is a superior candidate for regions with sufficient radiation. CCHP can also be used in sectors such as wastewater treatment units, desalination systems, and hydrogen production units to improve performance and increase productivity. The carbon and water footprints of CCHP systems are discussed in detail. The main drivers for reducing carbon and water footprints are improving system components such as the combustion engine and increasing productivity by expanding the system to multi-generation systems. Finally, the carbon tax index can help reduce carbon emissions if properly used in the right context. Based on our best knowledge, there is no extensive review of the environmental aspects of CCHP systems in the literature. Full article

(This article belongs to the Special Issue Recent Advances in Environmental Pollution Control and Coal Combustion)

► Show Figures

Figure 1

12 pages, 2134 KiB

Open AccessEditor’s ChoiceArticle

The Volume Stability of Alkali-Activated Electric Arc Furnace Ladle Slag Mortar and Its Performance at High Temperatures

by Tung-Hsuan Lu, Ying-Liang Chen, Hong-Paul Wang and Juu-En Chang

Processes 2022, 10(4), 700; https://doi.org/10.3390/pr10040700 - 5 Apr 2022

Cited by 2 | Viewed by 1631

Abstract

In this study, the engineering properties of Ordinary Portland Cement (OPC) and alkali-activated slag (AAS) mortar with electric arc furnace ladle slag (EAFLS) were investigated to reveal the effects of EAFLS on the expansion of cementitious mortars. Additionally, the effects of these two [...] Read more.

In this study, the engineering properties of Ordinary Portland Cement (OPC) and alkali-activated slag (AAS) mortar with electric arc furnace ladle slag (EAFLS) were investigated to reveal the effects of EAFLS on the expansion of cementitious mortars. Additionally, the effects of these two types of mortar were explored based on their compressive strength, especially at high temperatures. EAFLS in OPC mortars significantly reduced the compressive strength and caused serious soundness problems in the mortars after autoclaving due to the presence of free-CaO and free-MgO in the EAFLS slag. On the other hand, the AAS mortars produced with EAFLS had compressive strength comparable to ordinary OPC mortars and maintained soundness after autoclaving. During a 550 °C heat treatment, the OPC mortar cracked and lost residual strength, but the AAS mortar retained more than 90% of its residual strength. Even after an 800 °C heat treatment, the AAS mortar maintained 14% of its residual strength (about 4 MPa), sufficient to prevent the collapse of the specimen structure. The main reason is that alkali-activated technology can accelerate the hydration process and solve the delayed hydration problem. The results of this study indicated that EAFLS is suitable to partially replace the binder used in the production of AAS mortars, and the resulting AAS mortars have high volume stability, high compression strength, and good high temperature resistance. Full article

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

► Show Figures

Figure 1

15 pages, 1203 KiB

Open AccessEditor’s ChoiceReview

Isolation and Analysis of Carotenoids in Hungary from Zechmeister until Today

by Attila Agócs, Erika Turcsi, Veronika Nagy and József Deli

Processes 2022, 10(4), 707; https://doi.org/10.3390/pr10040707 - 5 Apr 2022

Viewed by 1828

Abstract

László Zechmeister, one of the most important pioneers of carotenoid chemistry, died 50 years ago. He founded a carotenoid research group in Pécs (Hungary), which is the only place in the world where carotenoid research has been conducted continuously over the past 95 [...] Read more.

László Zechmeister, one of the most important pioneers of carotenoid chemistry, died 50 years ago. He founded a carotenoid research group in Pécs (Hungary), which is the only place in the world where carotenoid research has been conducted continuously over the past 95 years. This review presents the life of Zechmeister and gives a summary about the evolution of the methods of analysis, isolation, and structure elucidation of carotenoids from the 1930s until today, based on the results of the research group founded by Zechmeister. Full article

(This article belongs to the Special Issue Control and Optimization of Extractive Methodologies and Analysis of Natural Products)

► Show Figures

Figure 1

14 pages, 3994 KiB

Open AccessEditor’s ChoiceArticle

Artificial Neural Network for Fast and Versatile Model Parameter Adjustment Utilizing PAT Signals of Chromatography Processes for Process Control under Production Conditions

by Mourad Mouellef, Glaenn Szabo, Florian Lukas Vetter, Christian Siemers and Jochen Strube

Processes 2022, 10(4), 709; https://doi.org/10.3390/pr10040709 - 5 Apr 2022

Cited by 11 | Viewed by 2292

Abstract

Preparative chromatography is a well-established operation in chemical and biotechnology manufacturing. Chromatography achieves high separation performances, but often has to deal with the yield versus purity trade-off as the optimization criterium regarding through-put. The initial trade-off is often disturbed by the well-known phenomenon [...] Read more.

Preparative chromatography is a well-established operation in chemical and biotechnology manufacturing. Chromatography achieves high separation performances, but often has to deal with the yield versus purity trade-off as the optimization criterium regarding through-put. The initial trade-off is often disturbed by the well-known phenomenon of chromatogram shifts over process lifetime, and has to be corrected by operators via adjustment of peak fraction cutting. Nevertheless, with regard to autonomous operation and batch to continuous processing modes, an advanced process control strategy is needed to identify and correct shifts from the optimal operation point automatically. Previous studies have already presented solutions for batch-to-batch variance and process control options with the aid of rigorous physico-chemical process modeling. These models can be implemented as distinct digital twins as well as statistical process operation data analyzers. In order to utilize such models for advanced process control (APC), the model parameters have to be updated with the aid of inline Process Analytical Technology (PAT) data to describe the actual operational status. This updating process also includes any operational change phenomena that occur, and its relation to their physico-chemical root cause. Typical phenomena are fluid dynamic changes due to packing breakage, channelling or compression as well as mass transfer and phase equilibrium-related separation performance decrease due to adsorbent aging or feed and buffer composition changes. In order to track these changes, an Artificial Neural Network (ANN) is trained in this work. The ANN training is in this first step, based on the simulation results of a distinct and previously experimentally validated process model. The model is implemented in the open source tool CasADi for Python. This allows the implementation of interfaces to process control systems, among others, with relatively low effort. Therefore, PAT signals can easily be incorporated for sufficient adjustment of the process model for appropriate process control. Further steps would be the implementation of optimization routines based on PAT and ANN predictions to derive optimal operation points with the model. Full article

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

► Show Figures

Figure 1

10 pages, 2428 KiB

Open AccessEditor’s ChoiceArticle

A Substrate Integrated Waveguide Resonator Sensor for Dual-Band Complex Permittivity Measurement

by Qian Chen, Zhuo Long, Naoki Shinohara and Changjun Liu

Processes 2022, 10(4), 708; https://doi.org/10.3390/pr10040708 - 5 Apr 2022

Cited by 8 | Viewed by 1808

Abstract

This paper presents a novel dual-band substrate integrated waveguide (SIW) sensor that is designed to measure the complex permittivities of liquids or solid powders at two industrial, scientific, and medical (ISM) frequencies simultaneously. Resonant frequencies and quality factors are obtained from S-parameter measurements [...] Read more.

This paper presents a novel dual-band substrate integrated waveguide (SIW) sensor that is designed to measure the complex permittivities of liquids or solid powders at two industrial, scientific, and medical (ISM) frequencies simultaneously. Resonant frequencies and quality factors are obtained from S-parameter measurements with the proposed SIW sensor, and applied to reconstructing the permittivities of materials under test through an artificial neural network. The water–ethanol mixed liquids were measured with the proposed sensor. The maximum deviations of the measured permittivities at 2.45 and 5.8 GHz are within 3% of literature results. The measurement by the proposed SIW sensor with artificial neural network reconstruction is accurate and efficient. Full article

(This article belongs to the Special Issue Microwave Applications in Chemistry and Materials Processing)

► Show Figures

Figure 1

14 pages, 3463 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Multi-Physic Modelling Insight into the Differences between Microwave and Conventional Heating for the Synthesis of TiO₂ Nanoparticles

by Giulia Poppi, Elena Colombini, Diego Salvatori, Alessio Balestri, Giovanni Baldi, Cristina Leonelli and Paolo Veronesi

Processes 2022, 10(4), 697; https://doi.org/10.3390/pr10040697 - 3 Apr 2022

Cited by 1 | Viewed by 2025

Abstract

Microwave-assisted synthesis of nanoparticles usually leads to a smaller and more uniformly distributed particle size compared to conventional heating (e.g., oil bath). Numerical simulation can help to obtain a better insight into the process in terms of temperature distribution or to evidence existing [...] Read more.

Microwave-assisted synthesis of nanoparticles usually leads to a smaller and more uniformly distributed particle size compared to conventional heating (e.g., oil bath). Numerical simulation can help to obtain a better insight into the process in terms of temperature distribution or to evidence existing different temperature profiles and heating rates between the two techniques. In this paper multi-physics numerical simulation is used to investigate the continuous flow synthesis of titanium oxide nanoparticles starting from alkoxide precursors. Temperature-dependent permittivity of reactants has been measured, including the effects of permanence at the maximum synthesis temperature. A temperature homogeneity index has been defined to compare microwave and conventional heating. Results show that when using microwave heating at 2450 MHz, in the investigated conditions, a much higher temperature homogeneity of the reactants is reached. Moreover, reactants experience different heating rates, depending on their position inside the microwave applicator, while this is almost negligible in the case of conventional heating. Full article

(This article belongs to the Special Issue Microwave Applications in Chemistry and Materials Processing)

► Show Figures

Figure 1

20 pages, 3078 KiB

Open AccessEditor’s ChoiceArticle

Characterization of Stressing Conditions in a High Energy Ball Mill by Discrete Element Simulations

by Christine Friederike Burmeister, Moritz Hofer, Palanivel Molaiyan, Peter Michalowski and Arno Kwade

Processes 2022, 10(4), 692; https://doi.org/10.3390/pr10040692 - 1 Apr 2022

Cited by 11 | Viewed by 3279

Abstract

The synthesis of sulfide solid electrolytes in ball mills by mechanochemical routes not only is efficient but also can enable the upscaling of material synthesis as required for the commercialization of solid-state battery materials. On a laboratory scale, the Emax high energy ball [...] Read more.

The synthesis of sulfide solid electrolytes in ball mills by mechanochemical routes not only is efficient but also can enable the upscaling of material synthesis as required for the commercialization of solid-state battery materials. On a laboratory scale, the Emax high energy ball mill accounts for high stresses and power densities, as well as for temperature control, to prevent damage to the material and equipment even for long process times. To overcome the merely phenomenological treatment, we characterized the milling process in an Emax by DEM simulations, using the sulfide solid electrolyte LPS as a model material for the calibration of input parameters to the DEM, and compared it to a planetary ball mill for a selected parameter set. We derived mechanistic model equations for the stressing conditions depending on the operation parameters of rotational speed, media size and filling ratio. The stressing conditions are of importance as they determine the outcome of the mechanochemical milling process, thus forming the basis for evaluating and interpreting experiments and for establishing scaling rules for the process transfer to larger mills. Full article

(This article belongs to the Special Issue Chemical Process Modelling and Simulation)

► Show Figures

Graphical abstract

25 pages, 6256 KiB

Open AccessEditor’s ChoiceArticle

Model-Based Analysis for Ethylene Carbonate Hydrogenation Operation in Industrial-Type Tubular Reactors

by Hai Huang, Chenxi Cao, Yue Wang, Youwei Yang, Jianning Lv and Jing Xu

Processes 2022, 10(4), 688; https://doi.org/10.3390/pr10040688 - 31 Mar 2022

Cited by 1 | Viewed by 3182

Abstract

Hydrogenation of ethylene carbonate (EC) to co-produce methanol (MeOH) and ethylene glycol (EG) offers an atomically economic route for CO₂ utilization. Herein, aided with bench and pilot plant data, we established engineering a kinetics model and multiscale reactor models for heterogeneous EC [...] Read more.

Hydrogenation of ethylene carbonate (EC) to co-produce methanol (MeOH) and ethylene glycol (EG) offers an atomically economic route for CO₂ utilization. Herein, aided with bench and pilot plant data, we established engineering a kinetics model and multiscale reactor models for heterogeneous EC hydrogenation using representative industrial-type reactors. Model-based analysis indicates that single-stage adiabatic reactors, despite a moderate temperature rise of 12 K, suffer from a narrow operational window delimited by EC condensation at lower temperatures and intense secondary EG hydrogenation at higher temperatures. Boiling water cooled multi-tubular reactors feature near-isothermal operation and exhibit better operability, especially under high pressure and low space velocity. Conduction oil-cooled reactors show U-type axial temperature profiles, rendering even wider operational windows regarding coolant temperatures than the water-cooled reactor. The revelation of operational characteristics of EC hydrogenation under industrial conditions will guide further improvement in reactor design and process optimization. Full article

(This article belongs to the Special Issue Industrial Chemistry Reaction: Kinetics, Mass Transfer and Industrial Reactor Design (II))

► Show Figures

Graphical abstract

27 pages, 27937 KiB

Open AccessEditor’s ChoiceArticle

Heat-Integration of Solar-Heated Membrane Distillation and Fuel Cell for Desalination System Based on the Dynamic Optimization Approach

by Yu-Hsin Liu, Vincentius Surya Kurnia Adi and Shing-Yi Suen

Processes 2022, 10(4), 663; https://doi.org/10.3390/pr10040663 - 29 Mar 2022

Cited by 2 | Viewed by 1844

Abstract

The heat integration feasibility of the proton exchange membrane fuel cell (PEMFC) coupled with the solar-heated direct contact membrane distillation (DCMD) module is evaluated in this study. The additional waste heat from the PEMFC increases the DCMD system’s ability to produce fresh water [...] Read more.

The heat integration feasibility of the proton exchange membrane fuel cell (PEMFC) coupled with the solar-heated direct contact membrane distillation (DCMD) module is evaluated in this study. The additional waste heat from the PEMFC increases the DCMD system’s ability to produce fresh water and electricity. Two systems units to be assessed mainly include a flat plate solar collector, a heat storage tank with an internal heat exchanger, and the DCMD module with and without the PEMFC module. The importance of daily operation continuity is emphasized through a preliminary dynamic simulation and proper sizing of the solar-heated DCMD distillation. Sensitivity analysis is implemented to analyze the relationship between the essential variables and the daily freshwater production. The design variables of both configurations are rigorously optimized in terms of minimum unit production cost (UPC). The proposed heat integration feasibility is evaluated to obtain critical insights on the design strategy of the hybrid systems. Full article

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

► Show Figures

Graphical abstract

11 pages, 1628 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Diffusion of Ethanol in Supercritical Carbon Dioxide—Investigation of scCO₂-Cosolvent Mixtures Used in Pharmaceutical Applications

by Cecília I. A. V. Santos, Marisa C. F. Barros and Ana C. F. Ribeiro

Processes 2022, 10(4), 660; https://doi.org/10.3390/pr10040660 - 29 Mar 2022

Cited by 4 | Viewed by 2553

Abstract

Diffusion coefficients, D, for ethanol in supercritical carbon dioxide (scCO₂) were measured in the temperature range 306.15–331.15 K and along the 10.5 MPa isobar, using the Taylor dispersion technique. The obtained diffusivities ranged from 1.49 × 10⁻⁸ to 2.98 [...] Read more.

Diffusion coefficients, D, for ethanol in supercritical carbon dioxide (scCO₂) were measured in the temperature range 306.15–331.15 K and along the 10.5 MPa isobar, using the Taylor dispersion technique. The obtained diffusivities ranged from 1.49 × 10⁻⁸ to 2.98 × 10⁻⁸ m² s⁻¹, an order of magnitude higher than in usual liquids. The dependence of D on temperature and solvent density was examined. Various correlation models based in the hydrodynamic theory were assessed to estimate the diffusion coefficients, with reasonable results obtained for the Wilke–Chang and Lai–Tan models. Full article

(This article belongs to the Special Issue Drug Delivery Systems: Theory, Methods and Applications)

► Show Figures

Figure 1

16 pages, 4189 KiB

Open AccessEditor’s ChoiceArticle

Coprocessing Corn Germ Meal for Oil Recovery and Ethanol Production: A Process Model for Lipid-Producing Energy Crops

by Yuyao Jia, Deepak Kumar, Jill K. Winkler-Moser, Bruce Dien, Kent Rausch, Mike E. Tumbleson and Vijay Singh

Processes 2022, 10(4), 661; https://doi.org/10.3390/pr10040661 - 29 Mar 2022

Cited by 3 | Viewed by 2868

Abstract

Efforts to engineer high-productivity crops to accumulate oils in their vegetative tissue present the possibility of expanding biodiesel production. However, processing the new crops for lipid recovery and ethanol production from cell wall saccharides is challenging and expensive. In a previous study using [...] Read more.

Efforts to engineer high-productivity crops to accumulate oils in their vegetative tissue present the possibility of expanding biodiesel production. However, processing the new crops for lipid recovery and ethanol production from cell wall saccharides is challenging and expensive. In a previous study using corn germ meal as a model substrate, we reported that liquid hot water (LHW) pretreatment enriched the lipid concentration by 2.2 to 4.2 fold. This study investigated combining oil recovery with ethanol production by extracting oil following LHW and simultaneous saccharification and co-fermentation (SSCF) of the biomass. Corn germ meal was again used to model the oil-bearing energy crops. Pretreated germ meal hydrolysate or solids (160 and 180 °C for 10 min) were fermented, and lipids were extracted from both the spent fermentation whole broth and fermentation solids, which were recovered by centrifugation and convective drying. Lipid contents in spent fermentation solids increased 3.7 to 5.7 fold compared to the beginning germ meal. The highest lipid yield achieved after fermentation was 36.0 mg lipid g⁻¹ raw biomass; the maximum relative amount of triacylglycerol (TAG) was 50.9% of extracted oil. Although the fermentation step increased the lipid concentration of the recovered solids, it did not improve the lipid yields of pretreated biomass and detrimentally affected oil compositions by increasing the relative concentrations of free fatty acids. Full article

(This article belongs to the Topic Chemical and Biochemical Processes for Energy Sources)

► Show Figures

Figure 1

23 pages, 1214 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Biocontrol Methods in Avoidance and Downsizing of Mycotoxin Contamination of Food Crops

by Manuela Zadravec, Ksenija Markov, Tina Lešić, Jadranka Frece, Danijela Petrović and Jelka Pleadin

Processes 2022, 10(4), 655; https://doi.org/10.3390/pr10040655 - 28 Mar 2022

Cited by 11 | Viewed by 4115

Abstract

By increasing the resistance of seeds against abiotic and biotic stress, the possibility of cereal mold contamination and hence the occurrence of secondary mold metabolites mycotoxins decreases. The use of biological methods of seed treatment represents a complementary strategy, which can be implemented [...] Read more.

By increasing the resistance of seeds against abiotic and biotic stress, the possibility of cereal mold contamination and hence the occurrence of secondary mold metabolites mycotoxins decreases. The use of biological methods of seed treatment represents a complementary strategy, which can be implemented as an environmental-friendlier approach to increase the agricultural sustainability. Whereas the use of resistant cultivars helps to reduce mold growth and mycotoxin contamination at the very beginning of the production chain, biological detoxification of cereals provides additional weapons against fungal pathogens in the later stage. Most efficient techniques can be selected and combined on an industrial scale to reduce losses and boost crop yields and agriculture sustainability, increasing at the same time food and feed safety. This paper strives to emphasize the possibility of implementation of biocontrol methods in the production of resistant seeds and the prevention and reduction in cereal mycotoxin contamination. Full article

(This article belongs to the Special Issue Ways/Opportunities of Decontamination Processes of Surface Moulds and Mycotoxins)

► Show Figures

Figure 1

23 pages, 2990 KiB

Open AccessEditor’s ChoiceArticle

Main Technical and Economic Guidelines to Implement Wind/Solar-Powered Reverse-Osmosis Desalination Systems

by Vicente J. Subiela-Ortín, Baltasar Peñate-Suárez and Juan A. de la Fuente-Bencomo

Processes 2022, 10(4), 653; https://doi.org/10.3390/pr10040653 - 28 Mar 2022

Cited by 11 | Viewed by 3817

Abstract

The use of renewable energy for desalination started in the 1980s, in order to provide a sustainable water supply in windy/sunny areas with water shortages. Nevertheless, this initiative has been generally limited to the R&D field and prototypes, with few units operating under [...] Read more.

The use of renewable energy for desalination started in the 1980s, in order to provide a sustainable water supply in windy/sunny areas with water shortages. Nevertheless, this initiative has been generally limited to the R&D field and prototypes, with few units operating under real conditions. The research tradition in this field carried out by the Canary Islands Institute of Technology, based on pilot facilities, resulted in wide expertise on practical issues, as well as a deep knowledge on the state of the art. This paper deals with the most relevant technical aspects to be considered in the optimal design and operation of wind/photovoltaic (PV)-powered reverse-osmosis (RO) systems, focusing on practical indications: appropriate pre-treatment, the use and selection of the RO energy recovery system (ERD), the selection of an energy storage system, key recommendations for the O&M actions in wind- and PV-powered RO systems (extracted from the experience of operating different units in remote locations (PV and RO) and coastal areas (wind and RO)), and an identification of the pros and cons of hybrid systems. A selection of economic data is given, indicating the main aspects of the minimization of the cost of water. Finally, the paper mentions the latest advances in the involved technologies. Full article

(This article belongs to the Special Issue Desalination Processes by Renewable Energy (RE))

► Show Figures

Figure 1

35 pages, 3773 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Successful Manufacturing Protocols of N-Rich Carbon Electrodes Ensuring High ORR Activity: A Review

by Malgorzata Skorupska, Anna Ilnicka and Jerzy P. Lukaszewicz

Processes 2022, 10(4), 643; https://doi.org/10.3390/pr10040643 - 25 Mar 2022

Cited by 10 | Viewed by 2401

Abstract

The exploration and development of different carbon nanomaterials happening over the past years have established carbon electrodes as an important electrocatalyst for oxygen reduction reaction. Metal-free catalysts are especially promising potential alternatives for replacing Pt-based catalysts. This article describes recent advances and challenges [...] Read more.

The exploration and development of different carbon nanomaterials happening over the past years have established carbon electrodes as an important electrocatalyst for oxygen reduction reaction. Metal-free catalysts are especially promising potential alternatives for replacing Pt-based catalysts. This article describes recent advances and challenges in the three main synthesis manners (i.e., pyrolysis, hydrothermal method, and chemical vapor deposition) as effective methods for the production of metal-free carbon-based catalysts. To improve the catalytic activity, heteroatom doping the structure of graphene, carbon nanotubes, porous carbons, and carbon nanofibers is important and makes them a prospective candidate for commercial applications. Special attention is paid to providing an overview on the recent major works about nitrogen-doped carbon electrodes with various concentrations and chemical environments of the heteroatom active sites. A detailed discussion and summary of catalytic properties in aqueous electrolytes is given for graphene and porous carbon-based catalysts in particular, including recent studies performed in the authors’ research group. Finally, we discuss pathways and development opportunities approaching the practical use of mainly graphene-based catalysts for metal–air batteries and fuel cells. Full article

(This article belongs to the Section Materials Processes)

► Show Figures

Figure 1

29 pages, 6834 KiB

Open AccessEditor’s ChoiceArticle

Advanced Dynamics Processes Applied to an Articulated Robot

by Florian Ion Tiberiu Petrescu

Processes 2022, 10(4), 640; https://doi.org/10.3390/pr10040640 - 24 Mar 2022

Cited by 5 | Viewed by 4012

Abstract

The paper presents the dynamics of a 2R planar articulated robot, developed by two original methods. One is the classical “Lagrangian” adapted by the author, and the second method is absolutely original. The dynamics of the robot are based in both cases on [...] Read more.

The paper presents the dynamics of a 2R planar articulated robot, developed by two original methods. One is the classical “Lagrangian” adapted by the author, and the second method is absolutely original. The dynamics of the robot are based in both cases on the variation of the inertial forces in the mechanism, or practically on the influence of the masses of the moving elements of the robot. The influence of external loads, weights and the load to be transported is also taken into account. Another original element of the work is the choice of speeds in such a way that they correspond to an optimum necessary for the inverse kinematics imposed on the robot. For this reason, the dynamic operation will be quiet and without large variations or vibrations. If the speeds of the two electric motors (preferably stepper motors) areadapted to those recommended by the author, the controller (PID) used will have a very light load. It is even possible to eliminate it if the adjustment of the two stepper motors (actuators) is performed according to the speeds indicated by the author of the paper. The kinematic motion imposed by the indicated optimal speeds is dynamically and successfully checked by both methods used. Full article

(This article belongs to the Special Issue Advanced Processes Creating New Technologies in Tomorrow's Industry)

► Show Figures

Figure 1

13 pages, 4954 KiB

Open AccessEditor’s ChoiceArticle

Development of Prediction Models for Pressure Loss and Classification Efficiency in Classifiers

by Michael Betz, Hermann Nirschl and Marco Gleiss

Processes 2022, 10(4), 627; https://doi.org/10.3390/pr10040627 - 23 Mar 2022

Cited by 1 | Viewed by 1715

Abstract

This paper presents the development of prediction models for pressure loss and classification efficiency in classifiers. Classifiers belong to one of the most important classification devices in gas particle processing and a fast and accurate determination of pressure loss and cut size is [...] Read more.

This paper presents the development of prediction models for pressure loss and classification efficiency in classifiers. Classifiers belong to one of the most important classification devices in gas particle processing and a fast and accurate determination of pressure loss and cut size is of great interest. The first model developed in this work allows the calculation of pressure loss as a function of geometric and operational parameters. It is based on a number of measured values that are obtained from previous numerical simulations (CFD). The maximum deviation of the model is less than 20% and the model operates in real time. However, the model requires calibration for each type of classifier. The second model for classification efficiency is based on a simplified two-dimensional approach in which the flow profile and particle trajectories are determined exclusively for the area between two classifier blades. The model is applicable for all geometrical and operational parameters and calculates the desired parameters within a few minutes, with a maximum error rate of 25%. In combination, the two models allow for the process optimization of classifiers in complete systems. Full article

► Show Figures

Figure 1

16 pages, 2222 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Biogenic Synthesis of Antibacterial, Hemocompatible, and Antiplatelets Lysozyme Functionalized Silver Nanoparticles through the One-Step Process for Therapeutic Applications

by Pravin Dudhagara, Jemisha Alagiya, Chintan Bhagat, Dushyant Dudhagara, Anjana Ghelani, Jigna Desai, Rajesh Patel, Ashaka Vansia, Dao Ngoc Nhiem, Yih-Yuan Chen and Douglas J. H. Shyu

Processes 2022, 10(4), 623; https://doi.org/10.3390/pr10040623 - 23 Mar 2022

Cited by 5 | Viewed by 2492

Abstract

To evaluate silver nanoparticles’ (AgNPs) therapeutic and clinical potentials, antibacterial action, blood compatibility, and antiplatelet activities are the main concerns for toxicity profiling. Heat-denatured lysozyme-mediated formulation stabilized the AgNPs, thereby providing more bactericidal activity and blood compatibility. The study of the synthesis of [...] Read more.

To evaluate silver nanoparticles’ (AgNPs) therapeutic and clinical potentials, antibacterial action, blood compatibility, and antiplatelet activities are the main concerns for toxicity profiling. Heat-denatured lysozyme-mediated formulation stabilized the AgNPs, thereby providing more bactericidal activity and blood compatibility. The study of the synthesis of AgNPs suggests the rapid and cost-effective formulation of AgNPs by one-step reaction using a 10:1 ratio of silver nitrate and lysozyme by incubating at 60 °C for two hours. Characterization of AgNPs was analyzed by UV–Visible spectroscopy, DLS, TEM, EDX, XRD, AFM, and FTIR, followed by antibacterial, hemocompatibility, and platelet aggregation testing. The average size of synthesized AgNPs was found to be 94.10 nm with 0.45 mV zeta potential and 0.293 polydispersity index by DLS. The TEM and EXD results indicated homogeneously 28.08 nm spherical-shaped pure formations of AgNPs. The XRD peaks showed the synthesis of small AgNPs with a crystallite size of 22.88 nm, while the AFM confirmed the homogeneity and smoothness of the monodispersed AgNPs. The FTIR spectra specified the coating of the lysozyme-derived amide group on the AgNPs surface, which provides stability and functionality of nanoparticles. The antibacterial activity of AgNPs was remarkable against six pathogenic bacteria and three multidrug resistance (MDR) strains (i.e., Escherichia coli, Klebsiella aerogenes, and Pseudomonas aeruginosa), which exhibited inhibition zones with diameters ranging between 13.5 ± 0.2 mm to 19.0 ± 0.3 mm. The non-hemolytic nature of the AgNPs was calculated by percentage hemolysis with four concentrations. The negative result of platelet aggregation using platelet-rich plasma suggests the antiplatelet effect of AgNPs. Only minor hemolysis of 6.17% in human erythrocytes and mild platelet aggregation of 1.98% were induced, respectively, by the use of 1000 µL of 1 mM AgNPs, which contains approximately 107.8 μg silver. The results indicated that the antiplatelet potency and non-hemolytic nature with the antibacterial action of the lysozyme functionalized AgNPs have a good chance to be used to solve in-stent restenosis and thrombosis issues of the coronary stent and may also have a possibility to use in vaccination to resolve the blood clotting problem. So, the optimized biogenic formulation of AgNPs offers promising opportunities to be used as a therapeutic agent. Full article

(This article belongs to the Special Issue Green Synthesis of Metallic Nanomaterials and Their Applications)

► Show Figures

Figure 1

21 pages, 5237 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Catalytic Properties of Free-Base Porphyrin Modified Graphite Electrodes for Electrochemical Water Splitting in Alkaline Medium

by Bogdan-Ovidiu Taranu and Eugenia Fagadar-Cosma

Processes 2022, 10(3), 611; https://doi.org/10.3390/pr10030611 - 21 Mar 2022

Cited by 10 | Viewed by 2742

Abstract

Hydrogen generation via electrochemical water splitting is considered an eco-friendly pathway for obtaining this desired alternative energy source, and it has triggered an intensive search for low cost and efficient catalysts. Within this context, four free-base porphyrins were studied as heterogeneous catalysts for [...] Read more.

Hydrogen generation via electrochemical water splitting is considered an eco-friendly pathway for obtaining this desired alternative energy source, and it has triggered an intensive search for low cost and efficient catalysts. Within this context, four free-base porphyrins were studied as heterogeneous catalysts for the oxygen and hydrogen evolution reactions (OER and HER) in alkaline aqueous solutions. TEM and STEM analyses of samples obtained by drop-casting the porphyrins from different organic solvents on TEM grids revealed a rich variety of aggregates due to the self-assembling property of the porphyrin molecules. Modified electrodes were manufactured by applying the four tetrapyrrolic macrocycles from various solvents on the surface of graphite supports, in one or more layers. Experiments performed in 0.1 M and 1 M KOH electrolyte solutions allowed the identification of the most electrocatalytically active electrodes for the OER and HER, respectively. In the first case, the electrode was manufactured by applying three layers of 5-(4-pyridyl)-10,15,20-tris(4-phenoxyphenyl)porphyrin on the graphite substrate from N,N-dimethylformamide solution was identified as overall catalytically superior. In the second case, the electrode obtained by applying one layer of 5,10,15,20-tetrakis(4-allyloxyphenyl)-porphyrin from benzonitrile solution displayed an HER overpotential value of 500 mV at i = −10 mA/cm² and a Tafel slope of 190 mV/dec. Full article

(This article belongs to the Special Issue From Small Molecules to High-Value Chemicals: Theory and Practice)

► Show Figures

Graphical abstract

28 pages, 9781 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Origin of Steam Contaminants and Degradation of Solid-Oxide Electrolysis Stacks

by Dominik Schäfer, Larissa Queda, Volker Nischwitz, Qingping Fang and Ludger Blum

Processes 2022, 10(3), 598; https://doi.org/10.3390/pr10030598 - 19 Mar 2022

Cited by 5 | Viewed by 2821

Abstract

Two once-through steam generators and a combination of a steam generator and a gas preheater for supplying feed gases to solid-oxide electrolysis stacks were evaluated for their carryover characteristics of contaminants from the feed-water into the steam phase. The concentrations of various trace [...] Read more.

Two once-through steam generators and a combination of a steam generator and a gas preheater for supplying feed gases to solid-oxide electrolysis stacks were evaluated for their carryover characteristics of contaminants from the feed-water into the steam phase. The concentrations of various trace impurities in the steam were determined by sampling the steam condensates and screening them with inductively coupled plasma–mass spectrometry for 19 elements and liquid ion chromatography and continuous flow analysis for chloride and ammonium. Steam-soluble species such as boric acid undergo complete volatilization and transfer into the steam phase. During unstable evaporation in the steam generators an extensive physical carryover of alloying metal species was observed. At realistic operation conditions for steam electrolysis, the gas preheater caused a considerable release of silicon into the steam phase. Two stack experiments were performed with common preheater temperatures and showed largely increased cell voltage degradation at higher operation temperatures. The post-test chemical analysis of cell samples revealed significant concentrations of silicon in the samples that are regarded as primary cause for increased degradation. These findings could partially explain the wide spread of degradation rates reported for solid-oxide steam electrolysis experiments. Full article

(This article belongs to the Section Energy Systems)

► Show Figures

Figure 1

20 pages, 5954 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Application of Nanodiamonds in Modelled Bioremediation of Phenol Pollution in River Sediments

by Ivaylo Yotinov, Mihaela Belouhova, Anna Foteva, Nora Dinova, Yovana Todorova, Irina Schneider, Elmira Daskalova and Yana Topalova

Processes 2022, 10(3), 602; https://doi.org/10.3390/pr10030602 - 19 Mar 2022

Cited by 3 | Viewed by 2478

Abstract

The pollution of aquatic ecosystems is a big problem that has its impact on river sediments. In recent decades, an effective solution to this problem has been the application of bioremediation technologies. Nanoremediation is an innovative part of these technologies. We still know [...] Read more.

The pollution of aquatic ecosystems is a big problem that has its impact on river sediments. In recent decades, an effective solution to this problem has been the application of bioremediation technologies. Nanoremediation is an innovative part of these technologies. We still know little about the efficiency of nanoparticles, especially nanodiamonds, in modelled conditions. The aim of the present study is to investigate the effect of nanodiamonds on the key parameters of modelled bioremediation of river sediments that are polluted with phenol, as well their effect on the structures and functions of microbial communities. An important indicative mechanism that was used is the application of fluorescent in situ hybridization for sediment microbial communities. The results of this study revealed the positive role of nanodiamonds that is associated with their intoxication with high concentrations of phenol. Readaptation was also found, in which the xenobiotic biodegradation potential evolved by increasing the relative proportions of non-culturable bacteria, namely Acinetobacter (at the 144th hour) and Pseudomonas (at the 214th hour). The results can help to find an effective solution to the question of how information from such precise molecular methods and the application of nanodiamonds can be translated into the accessible language of management and bioremediation technologies. Full article

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

► Show Figures

Graphical abstract

44 pages, 7089 KiB

Open AccessEditor’s ChoiceReview

Experimental Characterization Techniques for Solid-Liquid Slurry Flows in Pipelines: A Review

by Rui C. Silva

Processes 2022, 10(3), 597; https://doi.org/10.3390/pr10030597 - 18 Mar 2022

Cited by 15 | Viewed by 6811

Abstract

In industrial environments, having instrumentation able to attain fast, accurate, and autonomous measurements is pivotal to understanding the dynamics of liquid and particles during transport. Ideally, these instruments, consisting of either probes or sensors, should be robust, fast, and unintrusive, i.e., not cause [...] Read more.

In industrial environments, having instrumentation able to attain fast, accurate, and autonomous measurements is pivotal to understanding the dynamics of liquid and particles during transport. Ideally, these instruments, consisting of either probes or sensors, should be robust, fast, and unintrusive, i.e., not cause interference on the very flows being monitored, and require minimal maintenance. Beyond monitoring, the process knowledge gained through real time inspection allows teams to make informed technical decisions based on particle behavior, i.e., settling of particles causing pipe wear and clustering or blockages that can damage the unit or cause shutdowns, both of which with economical drawbacks. The purpose of this review is to examine experimental measurement techniques used to characterize physical properties and operational parameters of solid-liquid slurry flows, focusing on non-ionizing radiation methods. With this text the intent is not to provide an exhaustive examination of each individual technique but rather an overview on the most pertinent types of instrumentation, which will be presented, in addition to application examples from the literature, while directing the reader for pertinent seminal and review papers for a more in-depth analysis. Full article

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

► Show Figures

Figure 1

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 5 | Viewed by 1777

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)

► Show Figures

Graphical abstract

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 12 | Viewed by 3154

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)

► Show Figures

Figure 1

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 1 | Viewed by 2454

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)

► Show Figures

Figure 1

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 3 | Viewed by 2934

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)

► Show Figures

Graphical abstract

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 2153

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)

► Show Figures

Figure 1

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 12 | Viewed by 3238

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)

► Show Figures

Figure 1

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 1 | Viewed by 2525

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)

► Show Figures

Graphical abstract

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 2 | Viewed by 2173

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)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Editor’s Choice Articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI