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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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20 pages, 702 KiB  
Article
Hierarchical Deep LSTM for Fault Detection and Diagnosis for a Chemical Process
by Piyush Agarwal, Jorge Ivan Mireles Gonzalez, Ali Elkamel and Hector Budman
Processes 2022, 10(12), 2557; https://doi.org/10.3390/pr10122557 - 1 Dec 2022
Cited by 15 | Viewed by 3001
Abstract
A hierarchical structure based on a Deep LSTM Supervised Autoencoder Neural Network (Deep LSTM-SAE NN) is presented for the detection and classification of faults in industrial plants. The proposed methodology has the ability to classify incipient faults that are difficult to detect and [...] Read more.
A hierarchical structure based on a Deep LSTM Supervised Autoencoder Neural Network (Deep LSTM-SAE NN) is presented for the detection and classification of faults in industrial plants. The proposed methodology has the ability to classify incipient faults that are difficult to detect and diagnose with traditional and many recent methods. Faults are grouped into different subsets according to the degree of difficulty to classify them accurately in the proposed hierarchical structure. External pseudo-random binary signals (PRBS) are injected in the system to enhance the identification of incipient faults. The approach is illustrated on the benchmark process (Tennessee Eastman Process) in order to compare across different methodologies. The efficacy of the proposed method is shown by a comprehensive comparison between many recent and traditional fault detection and diagnosis methods in the literature for Tennessee Eastman Process. The proposed work results in significant improvements in the classification of faults over both multivariate linear model-based strategies and non-hierarchical nonlinear model-based strategies. Full article
(This article belongs to the Special Issue Manufacturing Industry 4.0: Trends and Perspectives)
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8 pages, 2009 KiB  
Article
Synthesis, Hydration Processes and Ionic Conductivity of Novel Gadolinium-Doped Ceramic Materials Based on Layered Perovskite BaLa2In2O7 for Electrochemical Purposes
by Nataliia Tarasova, Anzhelika Bedarkova, Irina Animitsa and Evgeniya Verinkina
Processes 2022, 10(12), 2536; https://doi.org/10.3390/pr10122536 - 29 Nov 2022
Cited by 7 | Viewed by 1979
Abstract
The search for novel highly effective materials with target properties for different electrochemical purposes is active for now. Ceramic materials with high levels of ionic conductivity can be applied as electrolytic materials in solid oxide fuel cells and in electrolyzers. Layered perovskites are [...] Read more.
The search for novel highly effective materials with target properties for different electrochemical purposes is active for now. Ceramic materials with high levels of ionic conductivity can be applied as electrolytic materials in solid oxide fuel cells and in electrolyzers. Layered perovskites are a novel class of ionic conductors demonstrating almost-pure proton transportation at mid-temperatures. Gadolinium-doped ceramic materials based on layered perovskite BaLa2In2O7 were obtained and investigated for the first time in this study. The effect of the dopant concentrations on the hydration processes and on ionic conductivity was revealed. It was shown that compositions 0 ≤ x ≤ 0.15 of BaLa2–xGdxIn2O7 exhibited proton conductivity when under wet air and at mid-temperatures (lower than ~450 °C). Gadolinium doping led to an increase in the conductivity values up to an order of magnitude of ~0.5. The protonic conductivity of the most conductive composition BaLa1.85Gd0.15In2O7 was 2.7∙10−6 S/cm at 400 °C under wet air. The rare earth doping of layered perovskites is a prospective approach for the design of ceramics for electrochemical devices for energy applications. Full article
(This article belongs to the Special Issue Electrochemical Technology for New Materials Synthesis and Reprocessing)
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12 pages, 1534 KiB  
Article
Improving the Efficiency and Antioxidant Activity of Essential Oil Extraction from Abies sachalinensis by Underwater Shockwave Pretreatment for the Construction of Low-Energy and Sustainable Essential Oil Extraction System
by Hideaki Kawai, Eisuke Kuraya, Akiko Touyama, Osamu Higa, Kazuki Tokeshi, Yoshie Tsujikawa, Kazuyuki Hokamoto and Shigeru Itoh
Processes 2022, 10(12), 2534; https://doi.org/10.3390/pr10122534 - 29 Nov 2022
Cited by 3 | Viewed by 2583
Abstract
Essential oils (EOs) from Abies sachalinensis (Sakhalin fir), a conifer species found in Sakhalin Island and Hokkaido in Japan, effectively remove nitrogen dioxide and possess antifungal activity. EOs also exert a relaxing effect and enhance air quality. Underwater shock waves generate instantaneous high [...] Read more.
Essential oils (EOs) from Abies sachalinensis (Sakhalin fir), a conifer species found in Sakhalin Island and Hokkaido in Japan, effectively remove nitrogen dioxide and possess antifungal activity. EOs also exert a relaxing effect and enhance air quality. Underwater shock waves generate instantaneous high pressure that ruptures cell walls, enhancing the performance of steam distillation and oil extraction. In this study, we aimed to increase the yield and quality of A. sachalinensis extracts using shockwaves. Leaves and branches were subjected to shockwave pretreatment or left untreated before EO extraction by steam distillation. EO yield of untreated dried leaves was 2.4 g/kg of dry leaf weight (DW). Upon application of a 3.0 kV, 3.6 kJ shockwave, the yield increased with the number of shockwave cycles. After ten cycles, yield increased 13.6-fold. Pretreatment with shockwaves for 10 cycles resulted in approximately 6- and 13-fold reductions in total energy consumption relative to fresh and dried leaves, respectively. Antioxidant activity increased more than 30-fold in shockwave-pretreated leaves than in untreated dried leaves after 10 cycles. This novel process can significantly reduce the energy used for EO extraction in steam distillation, thereby contributing to the development of a sustainable, low-energy EO production system. Full article
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13 pages, 711 KiB  
Article
Influence of Encapsulation Parameters on the Retention of Polyphenols in Blackthorn Flower Extract
by Nikolina Gaćina, Ivona Elez Garofulić, Zoran Zorić, Sandra Pedisić and Verica Dragović-Uzelac
Processes 2022, 10(12), 2517; https://doi.org/10.3390/pr10122517 - 28 Nov 2022
Cited by 5 | Viewed by 2691
Abstract
In order to utilize the benefits of blackthorn flower polyphenols and provide their stabilization during processing and storage, and to facilitate their application in functional food products, this study aimed to evaluate the encapsulation parameters during the spray-drying process of blackthorn flower extract. [...] Read more.
In order to utilize the benefits of blackthorn flower polyphenols and provide their stabilization during processing and storage, and to facilitate their application in functional food products, this study aimed to evaluate the encapsulation parameters during the spray-drying process of blackthorn flower extract. The effect of the type of wall material (maltodextrin (MD) and its mixtures with gum arabic (GA) and inulin (IN)), its ratio to extract dry matter (0.5, 1, and 2) and drying temperature (120, 150, and 180 °C) on the concentration of different polyphenolic groups was studied. While the lowest applied amount of wall material at the lowest drying temperature enabled efficient encapsulation of all polyphenolic groups, the type of wall material applied caused significant differences in retention. The highest concentrations of both phenolic acids and flavonoids were achieved with the addition of 25% of GA in MD. Unlike the addition of GA, mixtures of MD with IN did not show a positive effect on the retention of polyphenols. Selected encapsulation parameters ensured the high retention of total phenolics, namely 87.87% of the content determined in the liquid extract prior to spray drying, thereby providing a polyphenol-rich product with great potential for application in functional food and the nutraceutical industry. Full article
(This article belongs to the Special Issue Extraction, Isolation, Stabilization, and Identification of Plant Bioactives)
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18 pages, 2484 KiB  
Review
Comprehensive Review of Hydrothermal Pretreatment Parameters Affecting Fermentation and Anaerobic Digestion of Municipal Sludge
by Farokh Laqa Kakar, Frew Tadesse and Elsayed Elbeshbishy
Processes 2022, 10(12), 2518; https://doi.org/10.3390/pr10122518 - 28 Nov 2022
Cited by 9 | Viewed by 3829
Abstract
Municipal solid waste treatment and disposal have become one of the major concerns in waste management due to the excessive production of waste and higher levels of pollution. To address these challenges and protect the environment in sustainable ways, the hydrothermal pretreatment (HTP) [...] Read more.
Municipal solid waste treatment and disposal have become one of the major concerns in waste management due to the excessive production of waste and higher levels of pollution. To address these challenges and protect the environment in sustainable ways, the hydrothermal pretreatment (HTP) technique coupled with anaerobic digestion (AD) becomes a preferred alternative technology that can be used for municipal solid waste stabilization and the production of renewable energy. However, the impact of HTP parameters such as temperature, retention time, pH, and solid content on the fermentation of TWAS is yet to be well studied and analyzed. Hence this study was conducted to review the effect of hydrothermal pretreatment of thickened waste-activated sludge (TWAS) on fermentation and anaerobic digestion processes. Many studies reported that fermentation of TWAS at pretreatment temperature ranges from 160 °C to 180 °C resulted in a 50% increase in volatile fatty acid (VFA) yields compared to no pretreatment. However, for the AD process, HTP in the range of 175 °C to 200 °C with a 30–60 min retention time was considered the optimal condition for higher biogas production, with 30% increase in biodegradability and greater than 55% increase in biogas production. Even though there is a direct relationship between increased HTP temperature and the hydrolysis of TWAS, a pretreatment temperature range beyond 200 °C alters the biogas production. The solid content (SC) of sludge plays a crucial role in HTP, where in practice up to 16% SC has been utilized for HTP. Further, a combined alkaline-HTP enhances the process performance. Full article
(This article belongs to the Section Sustainable Processes)
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16 pages, 1560 KiB  
Article
Sustainable Operations of Last Mile Logistics Based on Machine Learning Processes
by Jerko Oršič, Borut Jereb and Matevž Obrecht
Processes 2022, 10(12), 2524; https://doi.org/10.3390/pr10122524 - 28 Nov 2022
Cited by 6 | Viewed by 3891
Abstract
The last-mile logistics is regarded as one of the least efficient, most expensive, and polluting part of the entire supply chain and has a significant impact and consequences on sustainable delivery operations. The leading business model in e-commerce called Attended Home Delivery is [...] Read more.
The last-mile logistics is regarded as one of the least efficient, most expensive, and polluting part of the entire supply chain and has a significant impact and consequences on sustainable delivery operations. The leading business model in e-commerce called Attended Home Delivery is the most expensive and demanding when a short delivery window is mutually agreed upon with the customer, decreasing possible optimizing flexibility. On the other hand, last-mile logistics is changing as decisions should be made in real time. This paper is focused on the proposed solution of sustainability opportunities in Attended Home Delivery, where we use a new approach to achieve more sustainable deliveries with machine learning forecasts based on real-time data, different dynamic route planning algorithms, tracking logistics events, fleet capacities and other relevant data. The developed model proposes to influence customers to choose a more sustainable delivery time window with important sustainability benefits based on machine learning to predict accurate time windows with real-time data influence. At the same time, better utilization of vehicles, less congestion, and fewer failures at home delivery are achieved. More sustainable routes are selected in the preplanning process due to predicted traffic or other circumstances. Increasing time slots from 2 to 4 h makes it possible to improve travel distance by about 5.5% and decrease cost by 11% if we assume that only 20% of customers agree to larger time slots. Full article
(This article belongs to the Special Issue Sustainable Supply Chains in Industrial Engineering and Management)
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26 pages, 13275 KiB  
Article
Fault Detection for CNC Machine Tools Using Auto-Associative Kernel Regression Based on Empirical Mode Decomposition
by Seunghwan Jung, Minseok Kim, Baekcheon Kim, Jinyong Kim, Eunkyeong Kim, Jonggeun Kim, Hyeonuk Lee and Sungshin Kim
Processes 2022, 10(12), 2529; https://doi.org/10.3390/pr10122529 - 28 Nov 2022
Cited by 9 | Viewed by 2983
Abstract
In manufacturing processes using computerized numerical control (CNC) machines, machine tools are operated repeatedly for a long period for machining hard and difficult-to-machine materials, such as stainless steel. These operating conditions frequently result in tool breakage. The failure of machine tools significantly degrades [...] Read more.
In manufacturing processes using computerized numerical control (CNC) machines, machine tools are operated repeatedly for a long period for machining hard and difficult-to-machine materials, such as stainless steel. These operating conditions frequently result in tool breakage. The failure of machine tools significantly degrades the product quality and efficiency of the target process. To solve these problems, various studies have been conducted for detecting faults in machine tools. However, the most related studies used only the univariate signal obtained from CNC machines. The fault-detection methods using univariate signals have a limitation in that multivariate models cannot be applied. This can restrict in performance improvement of the fault detection. To address this problem, we employed empirical mode decomposition to construct a multivariate dataset from the univariate signal. Subsequently, auto-associative kernel regression was used to detect faults in the machine tool. To verify the proposed method, we obtained a univariate current signal measured from the machining center in an actual industrial plant. The experimental results demonstrate that the proposed method successfully detects faults in the actual machine tools. Full article
(This article belongs to the Topic Artificial Intelligence in Smart Industrial Diagnostics and Manufacturing)
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20 pages, 2051 KiB  
Article
Investigating the Possibilities for Simulation of the Interconnected Electric Power and Communication Infrastructures
by Matej Vrtal, Jan Benedikt, Radek Fujdiak, David Topolanek, Petr Toman and Jiri Misurec
Processes 2022, 10(12), 2504; https://doi.org/10.3390/pr10122504 - 25 Nov 2022
Cited by 2 | Viewed by 2496
Abstract
In recent years, we have seen an increasing dependency between different urban critical infrastructures, which raises the demands on their analysis and cybersecurity. Current open-source solutions do not provide simulations of interconnected data networks and power grids, which are essential for analysing of [...] Read more.
In recent years, we have seen an increasing dependency between different urban critical infrastructures, which raises the demands on their analysis and cybersecurity. Current open-source solutions do not provide simulations of interconnected data networks and power grids, which are essential for analysing of both infrastructures weak parts and reducing the risk of emerging threats. The main purpose of this paper is to describe the design of a simulation platform that provides this type of simulation to customers using the virtual user interface. The paper describes the development of a complex model of interconnected power and data infrastructures. Created virtualization platform that consists of several open-source tools is described in detail. Outputs of this paper can be used for analysis of critical infrastructures at the level of urban networks. Full article
(This article belongs to the Special Issue Recent Advances in Electrical Power Engineering)
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18 pages, 3418 KiB  
Article
Doubling the Space-Time Yield of a Pilot Biogas Reactor with Swine Manure and Cereal Residues by a Closed Loop Feedback Control Based on an Automated Fuzzy Logic Control System
by Paul Scherer, Anja Schreiber, Richard Arthur, Sebastian Antonczyk and Gerhard-Rainer Vollmer
Processes 2022, 10(12), 2511; https://doi.org/10.3390/pr10122511 - 25 Nov 2022
Cited by 2 | Viewed by 2061
Abstract
The anaerobic digestion of swine manure was performed for more than 2 years in a biogas pilot plant with cereal residues as a mono-input, either by a simple intermittent substrate feeding or by feeding with an automated “autopilot” system under the direction of [...] Read more.
The anaerobic digestion of swine manure was performed for more than 2 years in a biogas pilot plant with cereal residues as a mono-input, either by a simple intermittent substrate feeding or by feeding with an automated “autopilot” system under the direction of a Fuzzy logic control (FLC) system, working with a closed-loop feedback control. The pilot plant of the University of Applied Sciences in Nordhausen consisted of a 2.5 m3 dosage tank, a 2.5 m3 digestate tank, and a 1 m3 biogas reactor. Only three control parameters were used for FLC: pH, methane %, and the specific gas production rate (GPR) related to the organic loading rate (OLR), that is GPR/OLR m3 biogas/(kgVS d), vs = volatile solids. The specific GPR was referred to the OLR of the last feeding every 8 h in terms of kgVS/(m3 d). In test period I without an FLC system, a safe process with just an OLR of 4 kgVS/(m3 d) was reached, followed by an overloading and reactor disturbance at ≤6.3 kgVS/(m3 d) as indicated by acidification with volatile fatty acids up to 25,000 mg/L. However, test period II (585 trial days) with an integrated FLC system allowed a safe OLR up to 11 kgVS/(m3 d). Apparently, the microbes themselves directed the speed of substrate feeding by the dynamics of their substrate turnover and by the closed loop feedback control, while the three FLC parameters prevented acidification. Therefore, the application of FLC enabled a doubling of the throughput for a biogas reactor in the same time with a ‘turbo speed’. The concomitant hydraulic residence time (HRT) of only 10 days reduced the stirring and heating costs. The usage of an FLC system should open the door for networked biogas production to enable flexible biogas production on demand. Full article
(This article belongs to the Special Issue Biochar-Bioenergy Production Systems)
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16 pages, 2630 KiB  
Article
Occurrence of Selected Emerging Contaminants in Southern Europe WWTPs: Comparison of Simulations and Real Data
by Daniel Sol, Andrea Menéndez-Manjón, Paula Arias-García, Amanda Laca, Adriana Laca, Amador Rancaño and Mario Díaz
Processes 2022, 10(12), 2491; https://doi.org/10.3390/pr10122491 - 23 Nov 2022
Cited by 9 | Viewed by 2230
Abstract
Emerging contaminants (ECs) include a diverse group of compounds not commonly monitored in wastewaters, which have become a global concern due to their potential harmful effects on aquatic ecosystems and human health. In the present work, six ECs (ibuprofen, diclofenac, erythromycin, triclosan, imidacloprid [...] Read more.
Emerging contaminants (ECs) include a diverse group of compounds not commonly monitored in wastewaters, which have become a global concern due to their potential harmful effects on aquatic ecosystems and human health. In the present work, six ECs (ibuprofen, diclofenac, erythromycin, triclosan, imidacloprid and 17α-ethinylestradiol) were monitored for nine months in influents and effluents taken from four wastewater treatment plants (WWTPs). Except for the case of ibuprofen, which was in all cases in lower concentrations than those usually found in previous works, results found in this work were within the ranges normally reported. Global removal efficiencies were calculated, in each case being very variable, even when the same EC and facility were considered. In addition, the SimpleTreat model was tested by comparing simulated and real ibuprofen, diclofenac and erythromycin data. The best agreement was obtained for ibuprofen which was the EC with the highest removal efficiencies. Full article
(This article belongs to the Special Issue Wastewater and Waste Treatment: Overview, Challenges and Current Trends)
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16 pages, 5429 KiB  
Article
Analysis of the Corrosion Process with the Application of the Novel Type of Coupon Installation
by Daniel Musik, Krzysztof Wójcik, Małgorzata Sekuła-Wybańska, Maciej Konopacki and Rafał Rakoczy
Processes 2022, 10(12), 2468; https://doi.org/10.3390/pr10122468 - 22 Nov 2022
Cited by 2 | Viewed by 2517
Abstract
The corrosion process leads to high power consumption, high maintenance costs and the loss of commercial income during downtime in various branches of industry. The proper methods to measure and forecast the corrosion process would help intervene in process production where corrosion is [...] Read more.
The corrosion process leads to high power consumption, high maintenance costs and the loss of commercial income during downtime in various branches of industry. The proper methods to measure and forecast the corrosion process would help intervene in process production where corrosion is a common phenomenon. Therefore, the main aim of this experimental study is to improve the widely used corrosion monitoring methods with corrosion coupons. As part of this work, the installation for testing corrosion process under controlled conditions and with the application of mild steel coupons is proposed. The measurement concept is to install the coupons in a stream with the corrosion liquid (these conditions should be controlled). The numerical simulations of the fluid flow in the coupon installation were carried out, and the obtained results in the form of a velocity map allowed us to propose the placement of the coupons in the tested installation in such a way that the flowing liquid evenly washed the coupon surface. The developed coupon installation was tested for aggressive corrosive conditions, which were assessed using the water stability indices (Langelier Saturation Index and Ryznar stability index). Moreover, the inductively coupled plasma optical emission spectroscopy analysis characterised the liquid samples from the tested coupon installation. The corrosion process for the applied conditions was defined based on the corrosion rate of the tested coupons. This process was also confirmed by obtaining the Raman spectrum for the used corrosion coupons. The obtained investigation contributes significantly by developing the novel coupon installation and demonstrating the procedure for testing the corrosion process with the application of coupons. This setup and method might be successfully applied for accelerated laboratory tests. Full article
(This article belongs to the Section Chemical Processes and Systems)
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12 pages, 3423 KiB  
Article
Investigation of Impulse and Continuous Discharge Characteristics of Large-Capacity Lithium-Ion Batteries
by Sergey V. Kuchak and Sergey V. Brovanov
Processes 2022, 10(12), 2473; https://doi.org/10.3390/pr10122473 - 22 Nov 2022
Cited by 1 | Viewed by 1830
Abstract
Lithium-ion batteries are one of the most popular and efficient energy storage devices. In this paper, the characteristics of high-capacity lithium-iron-phosphate batteries during the impulse and long-term operation modes of batteries with different levels of the discharge current are considered. A modified DP-model [...] Read more.
Lithium-ion batteries are one of the most popular and efficient energy storage devices. In this paper, the characteristics of high-capacity lithium-iron-phosphate batteries during the impulse and long-term operation modes of batteries with different levels of the discharge current are considered. A modified DP-model is proposed. The novelty of the model is the possibility to calculate the activation polarization parameters for different discharge currents. The state of charge is estimated using a high-order polynomial. Based on the developed model, transient processes with rapid load changes and the dependence of the battery voltage on the state of charge were obtained. Here, the model is intended to be used for the design of energy storage systems. The results showed that the DP-model is reliable under the tested conditions and can be used for the considered application. Full article
(This article belongs to the Special Issue Advanced Battery Material Design and Process)
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17 pages, 1727 KiB  
Article
Waste Feathers Processing to Liquid Fertilizers for Sustainable Agriculture—LCA, Economic Evaluation, and Case Study
by Kamila Vavrova, Lenka Wimmerova, Jaroslav Knapek, Jan Weger, Zdenek Keken, Frantisek Kastanek and Olga Solcova
Processes 2022, 10(12), 2478; https://doi.org/10.3390/pr10122478 - 22 Nov 2022
Cited by 5 | Viewed by 3985
Abstract
The poultry meat industry generates about 60 million tons of waste annually. However, such waste can serve as a cheap material source for sustainable liquid fertilizers or biostimulant production. Moreover, its practical potential associated with the circular economy is evident. One of the [...] Read more.
The poultry meat industry generates about 60 million tons of waste annually. However, such waste can serve as a cheap material source for sustainable liquid fertilizers or biostimulant production. Moreover, its practical potential associated with the circular economy is evident. One of the options for waste feather reprocessing is to use a hydrolysis process, whose operating parameters vary depending on the waste material used. The better the quality of the waste feathers, the less energy is needed; moreover, a higher yield of amino acids and peptides can be achieved. These are the main operational parameters that influence the overall environmental and economic performance of the hydrolysis process. The assessment of process operational environmental aspects confirmed that the environmental impacts of hydrolysate production are highly dependent on the amount of electricity required and its sources. This fact influences the midpoint and the endpoint impacts on the observed environmental impact categories. It also minimizes the pressure associated with fossil resource scarcity and the related impact on climate change. During an economic evaluation of the process, it was found that the option of processing more fine waste, such as CGF, provided a 5% saving in energy costs related to the reduction in the cost per liter of hydrolysate of 4.5%. Finally, a case study experiment confirmed the fertilizing effect of the hydrolysate on pepper plants (biometric parameters, yield). Thus, the hydrolysate produced from the waste feathers can serve as a substitute for nitrate fertilizing, which is commonly drawn from raw fossil materials. Full article
(This article belongs to the Topic Advances in Biomass Conversion)
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20 pages, 1030 KiB  
Review
Tertiary Wastewater Treatment Technologies: A Review of Technical, Economic, and Life Cycle Aspects
by Dimitris P. Zagklis and Georgios Bampos
Processes 2022, 10(11), 2304; https://doi.org/10.3390/pr10112304 - 5 Nov 2022
Cited by 36 | Viewed by 12108
Abstract
The activated sludge process is the most widespread sewage treatment method. It typically consists of a pretreatment step, followed by a primary settling tank, an aerobic degradation process, and, finally, a secondary settling tank. The secondary effluent is then usually chlorinated and discharged [...] Read more.
The activated sludge process is the most widespread sewage treatment method. It typically consists of a pretreatment step, followed by a primary settling tank, an aerobic degradation process, and, finally, a secondary settling tank. The secondary effluent is then usually chlorinated and discharged to a water body. Tertiary treatment aims at improving the characteristics of the secondary effluent to facilitate its reuse. In this work, through a literature review of the most prominent tertiary treatment methods, a benchmarking of their technical efficiency, economic feasibility, and environmental impact was carried out. The photo-Fenton method proved to be the most technically efficient process, significantly reducing the microbial load and pharmaceutical content (by 4.9 log and 84%, respectively) of the secondary effluent. Chlorination and UV irradiation exhibited the lowest treatment costs (0.004 EUR/m−3) and the lowest global warming potential (0.04 and 0.09 kg CO2eq. m−3, respectively). After all the data were aggregated, a decision-making tool was constructed in the form of a ternary diagram, which indicates the most appropriate tertiary treatment method according to the weight-per-process aspect (technical, economic, and environmental) selected by the user, with chlorination, UV irradiation, ozonation, microalgae cultivation, and constructed wetlands prevailing in the final results. Full article
(This article belongs to the Special Issue Wastewater and Waste Treatment: Overview, Challenges and Current Trends)
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13 pages, 3607 KiB  
Article
Utilization of Carbon Dioxide via Catalytic Hydrogenation Processes during Steam-Based Enhanced Oil Recovery
by Firdavs Aliev, Oybek Mirzaev, Temurali Kholmurodov, Olga Slavkina and Alexey Vakhin
Processes 2022, 10(11), 2306; https://doi.org/10.3390/pr10112306 - 5 Nov 2022
Cited by 12 | Viewed by 2400
Abstract
The concentration of carbon dioxide in the atmosphere has been increasing since immediately after the boom of industrialization. Novel technologies are required for carbon dioxide (CO2) capture, storage, and its chemical conversion into value-added products. In this study, we present a [...] Read more.
The concentration of carbon dioxide in the atmosphere has been increasing since immediately after the boom of industrialization. Novel technologies are required for carbon dioxide (CO2) capture, storage, and its chemical conversion into value-added products. In this study, we present a novel in situ CO2 utilization method via a hydrogenation process in the presence of nickel tallates during steam-based enhanced oil recovery. The light n-alkanes are the preferred products of in situ catalytic hydrogenation of CO2 due to their effective solubility, viscosity-reducing capacity, and hydrogen-donating capacity. A nickel tallate was evaluated for its carbon dioxide hydrogenation and oil-upgrading performance at 300 °C. The results showed that the content of saturated and aromatic fractions increased, while the content of heavier fragments decreased. Moreover, the relative content of normal C10–C20 alkanes doubled after the catalytic hydrogenation of CO2. Despite the noncatalytic hydrogenation of CO2, the viscosity was altered from 3309 mPa.s to 1775 mPa.s at a shear rate of 0.66 s−1. The addition of the catalyst further contributed to the reduction of the viscosity, down to 1167 mPa.s at the same shear rate. Thus, in situ catalytic hydrogenation of CO2 not only significantly reduces the concentration of anthropogenic carbon dioxide gas in the atmosphere, but it also enhances the oil-recovery factor by improving the quality of the upgraded crude oil and its mobility. Full article
(This article belongs to the Special Issue In-Situ and Ex-situ Processes during Production, Transportation and Refinery of Heavy Oil)
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26 pages, 1065 KiB  
Review
Bioactive Compounds from Elderberry: Extraction, Health Benefits, and Food Applications
by Oana-Elena Pascariu and Florentina Israel-Roming
Processes 2022, 10(11), 2288; https://doi.org/10.3390/pr10112288 - 4 Nov 2022
Cited by 26 | Viewed by 15190
Abstract
Elderberries are appreciated for their antioxidant properties. Sambucus nigra L. is an extremely abundant plant in the wild flora of Romania, but it is underutilized. Elderberry is used in modern and traditional medicine due to the complex chemical composition of the fruit. The [...] Read more.
Elderberries are appreciated for their antioxidant properties. Sambucus nigra L. is an extremely abundant plant in the wild flora of Romania, but it is underutilized. Elderberry is used in modern and traditional medicine due to the complex chemical composition of the fruit. The content of phenolic compounds is high (516–8974 mg/100 g DW), of which the most abundant are anthocyanins. Phenolic compounds are known for their beneficial effects on the body. Numerous studies have demonstrated the antioxidant capacity, antibacterial, antiviral, antidiabetic, and anticancer properties of the fruit. It is considered that most of the therapeutic properties of elderberries can be correlated with the antioxidant activity they have. S. nigra fruits are also used in the food industry. Some studies have shown that the therapeutic properties of elderberries can also be found in the products obtained from them. Therefore, this review aimed to describe the chemical composition of elderberries and products obtained from them, the positive effects on the body, and the methods by which the bioactive compounds can be extracted from the fruits and analyzed. This manuscript is useful for extraction optimization and characterization in order to valorize new functional foods, food supplements, and also in new pharmaceutical products. Full article
(This article belongs to the Special Issue Bio-Active Compounds in Food Production)
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11 pages, 2449 KiB  
Article
Biodegradation of Alachlor by a Newly Isolated Bacterium: Degradation Pathway and Product Analysis
by Hyosun Lee and Dong-Uk Kim
Processes 2022, 10(11), 2256; https://doi.org/10.3390/pr10112256 - 2 Nov 2022
Cited by 5 | Viewed by 1792
Abstract
Alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl]acetamide] is a chloroacetanilide herbicide and has been widely used as a selective pre-emergent and post-emergent herbicide to control weeds and grass. Due to its wide usage, direct application on the ground, high solubility in water, and moderate [...] Read more.
Alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl]acetamide] is a chloroacetanilide herbicide and has been widely used as a selective pre-emergent and post-emergent herbicide to control weeds and grass. Due to its wide usage, direct application on the ground, high solubility in water, and moderate persistence, alachlor and its metabolites have been detected in various environments. Therefore, there is an increasing concern about the environmental fate of alachlor and its metabolites. Microbial biodegradation is a main method of removal of alachlor in the natural environment. In this study, we isolated new alachlor degrading bacterium and proposed a novel alachlor-degrading pathway. The alachlor-degrading bacterial strain, GC-A6, was identified as Acinetobacter sp. using 16S rRNA gene sequence analysis. Acinetobacter sp. GC-A6 utilized alachlor as its sole carbon source and degraded 100 mg L−1 of alachlor within 48 h, which was the highest alachlor degradation efficiency. The degradation pathway of alachlor was studied using GC-MS analysis. Alachlor was initially degraded to 2-chloro-N-(2,6-diethylphenyl) acetamide, which was further degraded to 2,6-diethylaniline and 7-ethylindoline, respectively. 2,6-Diethylaniline was transformed into N-(2,6-diethylphenyl) formamide. N-(2,6-diethylphenyl) formamide was a first-reported intermediate during the degrading pathway of alachlor by single isolate. Full article
(This article belongs to the Section Environmental and Green Processes)
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14 pages, 2587 KiB  
Article
Multi-Response Modelling and Optimisation of Mechanical Properties of Al-Si Alloy Using Mixture Design of Experiment Approach
by M. Poornesh, Shreeranga Bhat, E. V. Gijo, Pavana Kumara Bellairu and Olivia McDermott
Processes 2022, 10(11), 2246; https://doi.org/10.3390/pr10112246 - 1 Nov 2022
Cited by 9 | Viewed by 2189
Abstract
The research aims to produce, model, and optimise the mechanical properties of novel composite material through a structured multidisciplinary approach. The primary objective is to combine materials science, mechanical engineering, and statistical concepts to ensure Design for Manufacturability (DFM) from the industrial perspective. [...] Read more.
The research aims to produce, model, and optimise the mechanical properties of novel composite material through a structured multidisciplinary approach. The primary objective is to combine materials science, mechanical engineering, and statistical concepts to ensure Design for Manufacturability (DFM) from the industrial perspective. More specifically, the article is intended to determine the optimal mixture components and predictive model of Al-Si alloy with Al2O3 by accommodating multi-responses that enable DFM. The study adopted ASTM standards to prepare and test the novel composite material. Additionally, the Mixture Design of Experiment (DOE) approach was used to design the experimentation and subsequent analysis. In addition, microstructural images, Cox Response Trace plot, and Response Optimiser plot are effectively utilised to draw robust inferences. For multi-response modelling and optimisation, the composite material’s mechanical properties, like impact strength, hardness, density, and tensile strength, are considered. The study determines that innovative composite material will yield better results when Al-Alloy is 94.65 wt% and Al2O3 is 5.35 wt% from a multi-responses perspective. Further, it provides predictive models with a high level of predictability. Besides, the research shows that novel composite material has better mechanical properties from a practical perspective. The article not only provides the mechanical properties of a new class of material but also shows the effective utilisation of material science and statistical concepts to develop the novel material in a structured manner. This composite material can be used as a replacement for various parts of automobiles and aircraft. Additionally, researchers can use the article’s modelling and optimisation approach as a paradigm to create durable composite materials. Full article
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11 pages, 431 KiB  
Article
Beneficiation of Magnetically Separated Iron-Containing Ore Waste
by Kanat Chokin, Abdraman Yedilbayev, Vladimir Yugai and Alexandr Medvedev
Processes 2022, 10(11), 2212; https://doi.org/10.3390/pr10112212 - 27 Oct 2022
Cited by 1 | Viewed by 2209
Abstract
Rough processing of iron ore employs dry methods which means that equipment is tuned to process large particles, but fine magnetic material less than a few tenths of a millimeter in size is not separated as efficiently. The relevance of this study is [...] Read more.
Rough processing of iron ore employs dry methods which means that equipment is tuned to process large particles, but fine magnetic material less than a few tenths of a millimeter in size is not separated as efficiently. The relevance of this study is determined by the fact that dry beneficiation waste contains recoverable iron-bearing magnetite of commercial value. Commercial justification of waste beneficiation is associated with mining and grinding costs that are already included in the prime cost of the commercial concentrate. The future of tailings retreatment prospects depends on technology and efficiency of the employed equipment, the development of which is the subject of this paper. At first stage, fine iron is recovered by air sizing, with pitched curtain air classifiers embedding simple design and high performance. Powder materials were magnetically separated by a manufactured drum-type separator in which, to increase the separation efficiency, the process was performed at increased drum rotation speeds using Nd-Fe-B magnets and a drum made of electrically non-conductive materials. The separator performance was determined for various rotation speeds of the drum. Research has proven that a multi-stage magnetic separation with a consequent increase in drum rpm is reasonable. A new cascade separator was manufactured and tested for this purpose. It is shown that iron-containing ore tailings beneficiation is optimal without any additional grinding. Full article
(This article belongs to the Section Manufacturing Processes and Systems)
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13 pages, 3057 KiB  
Article
Improved Pilot-Plant-Scale Synthesis of Chlorin e6 and Its Efficacy as a Photosensitizer for Photodynamic Therapy and Photoacoustic Contrast Agent
by Til Bahadur Thapa Magar, Rajeev Shrestha, Pallavi Gurung, Junmo Lim and Yong-Wan Kim
Processes 2022, 10(11), 2215; https://doi.org/10.3390/pr10112215 - 27 Oct 2022
Cited by 8 | Viewed by 3185
Abstract
Photodynamic therapy and photoacoustic (PA) imaging are emerging therapeutic modalities for the diagnosis and treatment of various types of cancer or other diseases. In this study, the second-generation photosensitizer Chlorin e6 was prepared on a pilot scale by using the rapid, simple, and [...] Read more.
Photodynamic therapy and photoacoustic (PA) imaging are emerging therapeutic modalities for the diagnosis and treatment of various types of cancer or other diseases. In this study, the second-generation photosensitizer Chlorin e6 was prepared on a pilot scale by using the rapid, simple, and green synthetic method as compared to a conventional protocol. In the modified method, the extraction/reaction time and volume of solvents were significantly reduced. The dark and photodynamic cytotoxicity of Ce6 was measured against B16F10 melanoma cell line. Ce6 did not affect cancer cells in the dark up to 192 µM, ensuring their safety in the absence of light. After PDT, it displayed significant cytotoxicity at lower concentrations (IC50: 18.9 µM). For in vivo study, B16F10 allograft mice were treated with Ce6 at 2.5 mg/kg and then exposed to red light (660 nm) after 3 h. The Ce6-PDT caused the inhibition of tumor growth. Furthermore, Ce6 was also used as a photoacoustic imaging agent in ICR mice to visualize the internal organs. Therefore, this study provides valuable information about Ce6-PDT as a promising strategy for anti-cancer therapy as well as visualization of internal organs without surgery or x-rays. Full article
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15 pages, 5683 KiB  
Article
Deep-Learning Algorithmic-Based Improved Maximum Power Point-Tracking Algorithms Using Irradiance Forecast
by Chan Roh
Processes 2022, 10(11), 2201; https://doi.org/10.3390/pr10112201 - 26 Oct 2022
Cited by 7 | Viewed by 2408
Abstract
Renewable energy is a key technology for achieving carbon-free energy transitions, and solar power systems are one of the most reliable resources for achieving this. Solar power systems have a simple structure and are inexpensive. However, depending on the input irradiance, the existing [...] Read more.
Renewable energy is a key technology for achieving carbon-free energy transitions, and solar power systems are one of the most reliable resources for achieving this. Solar power systems have a simple structure and are inexpensive. However, depending on the input irradiance, the existing maximum output control algorithm (P&O) has disadvantages due to its slow transient response and steady-state vibration. Therefore, in this paper, we propose a maximum output control algorithm based on a deep learning algorithm that can predict the input irradiance. This can achieve a quick transient response and steady-state stability. The proposed method predicts the irradiance based on the output voltage/current and power of the photovoltaic (PV) system and calculates the duty ratio that can accurately follow the maximum output point according to the irradiance. The deep learning model applied in this study was trained based on the experimental results using a 100 W PV panel, and the performance of the proposed algorithm was verified by comparing its performance with that of the conventional algorithm under various input irradiance conditions. The proposed algorithm exhibits a maximum efficiency increase of 11.24% under the same input conditions as those of the existing algorithms. Full article
(This article belongs to the Special Issue Innovative Technology for Low Carbon Development)
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20 pages, 6086 KiB  
Article
Identification and Mapping of Three Distinct Breakup Morphologies in the Turbulent Inertial Regime of Emulsification—Effect of Weber Number and Viscosity Ratio
by Andreas Håkansson, Peyman Olad and Fredrik Innings
Processes 2022, 10(11), 2204; https://doi.org/10.3390/pr10112204 - 26 Oct 2022
Cited by 6 | Viewed by 2714
Abstract
Turbulent emulsification is an important unit operation in chemical engineering. Due to its high energy cost, there is substantial interest in increasing the fundamental understanding of drop breakup in these devices, e.g., for optimization. In this study, numerical breakup experiments are used to [...] Read more.
Turbulent emulsification is an important unit operation in chemical engineering. Due to its high energy cost, there is substantial interest in increasing the fundamental understanding of drop breakup in these devices, e.g., for optimization. In this study, numerical breakup experiments are used to study turbulent fragmentation of viscous drops, under conditions similar to emulsification devices such as high-pressure homogenizers and rotor-stator mixers. The drop diameter was kept larger than the Kolmogorov length scale (i.e., turbulent inertial breakup). When varying the Weber number (We) and the disperse-to-continuous phase viscosity ratio in a range applicable to emulsification, three distinct breakup morphologies are identified: sheet breakup (large We and/or low viscosity ratio), thread breakup (intermediary We and viscosity ratio > 5), and bulb breakup (low We). The number and size of resulting fragments differ between these three morphologies. Moreover, results also confirm previous findings showing drops with different We differing in how they attenuate the surrounding turbulent flow. This can create ‘exclaves’ in the phase space, i.e., narrow We-intervals, where drops with lower We break and drops with higher We do not (due to the latter attenuating the surrounding turbulence stresses more). Full article
(This article belongs to the Special Issue Nanoemulsion Processes Design and Applications)
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35 pages, 2044 KiB  
Article
A Multiple Solution Approach to Real-Time Optimization
by Jack Speakman and Grégory François
Processes 2022, 10(11), 2207; https://doi.org/10.3390/pr10112207 - 26 Oct 2022
Cited by 2 | Viewed by 1893
Abstract
Modifier Adaptation (MA) is a method of real-time optimization (RTO) which modifies a single model to match the first order properties of the plant. Known uncertainties in the parameters of this model are discarded in favor of real-time measurements, but they can be [...] Read more.
Modifier Adaptation (MA) is a method of real-time optimization (RTO) which modifies a single model to match the first order properties of the plant. Known uncertainties in the parameters of this model are discarded in favor of real-time measurements, but they can be used to quantify the mismatch between the plant and model. Using multi-model methods increases the computation time, but can improve rate of convergence of the RTO scheme. This article proposes a framework, known as multiple solution modifier adaptation (MSMA), which produces several models which are all modified in the same way as standard MA, each producing a potential solution to be applied to the plant. From this framework, three recommended schemes are proposed on how to select the operating point to be applied to the plant: (1) Selecting the solution based off the modifiers; (2) Selecting the mean solution from convex models; (3) Selecting the closest solution to the current operating point. Each of these methods have different advantages, including limiting the increase in computational complexity and improving the model adequacy conditions of the scheme. These recommended schemes are shown on three different case studies of varying complexity with all three schemes showing improvements over standard MA. Full article
(This article belongs to the Section Process Control and Monitoring)
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16 pages, 11530 KiB  
Article
High-Temperature Pyrolysis for Elimination of Per- and Polyfluoroalkyl Substances (PFAS) from Biosolids
by Hanieh Bamdad, Sadegh Papari, Emma Moreside and Franco Berruti
Processes 2022, 10(11), 2187; https://doi.org/10.3390/pr10112187 - 25 Oct 2022
Cited by 27 | Viewed by 7636
Abstract
Biosolids generated as byproducts of wastewater treatment processes are widely used as fertilizer supplements to improve soil condition and ultimately agricultural products yields and quality. However, biosolids may contain toxic compounds, i.e., per- and polyfluoroalkyl substances (PFAS), which can end up in soils, [...] Read more.
Biosolids generated as byproducts of wastewater treatment processes are widely used as fertilizer supplements to improve soil condition and ultimately agricultural products yields and quality. However, biosolids may contain toxic compounds, i.e., per- and polyfluoroalkyl substances (PFAS), which can end up in soils, groundwater, and surface water, causing adverse environmental and health effects. The purpose of this study was to investigate the application of High-Temperature Pyrolysis (HTP) treatment for biosolids management, and its efficacy in eliminating PFAS from the solid fraction. Biosolid samples were pyrolyzed at two different temperatures, 500 and 700 °C, in a continuous bench-scale pyrolysis unit. The major finding is that the treatment process at higher pyrolysis temperatures can remarkably reduce or eliminate the level of PFAS (by ~97–100 wt%) in the resulting biochar samples. Full article
(This article belongs to the Special Issue Biochemical Processes for Sustainability)
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27 pages, 2039 KiB  
Review
Integration of Maintenance Management System Functions with Industry 4.0 Technologies and Features—A Review
by Basheer Wasef Shaheen and István Németh
Processes 2022, 10(11), 2173; https://doi.org/10.3390/pr10112173 - 24 Oct 2022
Cited by 35 | Viewed by 9322
Abstract
Industry 4.0 is the latest technological age, in which recent technological developments are being integrated within industrial systems. Consequently, maintenance management of current industrial manufacturing systems is affected by the emergence of the technologies and features of Industry 4.0. This study aimed to [...] Read more.
Industry 4.0 is the latest technological age, in which recent technological developments are being integrated within industrial systems. Consequently, maintenance management of current industrial manufacturing systems is affected by the emergence of the technologies and features of Industry 4.0. This study aimed to conduct a comprehensive literature review to understand how Industry 4.0 technologies and features affect the various functions of maintenance management systems. The reviewing process was initiated by examining the most recent related literature in three different databases. In total, 54 articles were classified into three research categories. Then, the integration of the main functions and components of the adopted maintenance management model and the Industry 4.0 features and technologies were aligned, focusing on the driving force of predictive maintenance. The analysis focused mainly on the technical aspects of the integration process, including integration concepts and integration-assisting tools, identifying the main applications and highlighting the challenges identified in the analysed literature. The key findings were that the main functions of maintenance management systems are significantly influenced by different Industry 4.0 technologies, mainly artificial intelligence–machine learning, CPS, IoT, big data, augmented reality, and cloud computing, in terms of successful integration. Consequently, the overall system implied tangible improvements through the involvement of different Industry 4.0 features which promote real-time condition monitoring, enable data management and curation, increase coordination between various maintenance tasks, facilitate supervision through remote maintenance applications, and, overall, improve operations and productivity, reduce unplanned shutdowns and, as a result, reduce the associated costs. To provide research directions, examples, and methodologies for integrating the various maintenance management system functions with the cutting-edge Industry 4.0 technologies and features based on real and practical cases present in the reviewed literature, the review’s findings are comprehensively categorised and summarised. Full article
(This article belongs to the Special Issue Manufacturing Industry 4.0: Trends and Perspectives)
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13 pages, 3245 KiB  
Article
Hydrothermal In-Reservoir Upgrading of Heavy Oil in the Presence of Non-Ionic Surfactants
by Temurali Kholmurodov, Firdavs Aliev, Oybek Mirzaev, Aleksey Dengaev, Arash Tajik and Alexey Vakhin
Processes 2022, 10(11), 2176; https://doi.org/10.3390/pr10112176 - 24 Oct 2022
Cited by 13 | Viewed by 2138
Abstract
The most widely applied methods to unlock heavy oil and natural bitumen resources in the world are still based on steam injection techniques. Improving the efficiency of hydrothermal processes poses a great challenge. The co-injection of various additives is practiced to lower the [...] Read more.
The most widely applied methods to unlock heavy oil and natural bitumen resources in the world are still based on steam injection techniques. Improving the efficiency of hydrothermal processes poses a great challenge. The co-injection of various additives is practiced to lower the steam-to-oil ratio (SOR), viscosity alteration and to improve heavy oil properties. Organic solvents, non-condensable gases, air and surfactants are the preferred chemicals to be combined with steam. This study provides an investigation of the surfactant-assisted hydrothermal upgrading of heavy oil at 200 °C. The thermal stability and salt resistivity of two non-ionic surfactants (SA–3 and Biolub Green) were investigated. Moreover, the improved performance of the surfactants was established by performing an SARA analysis, elemental analysis, FT-IR spectroscopy, and EPR analysis, and by studying the viscosity reduction degree. The experimental results showed that surfactants lead to the in-depth destructive hydrogenation of the high-molecular components of heavy oil such as resins and asphaltenes. However, the content of light fractions increased. According to the results of the elemental analysis, the surfactants assist in the hydrodesulphurization of heavy oil. Overall, the physical and chemical consequences of hydrothermal upgrading in the presence of surfactants led to the irreversible viscosity reduction of heavy oil. Full article
(This article belongs to the Special Issue In-Situ and Ex-situ Processes during Production, Transportation and Refinery of Heavy Oil)
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22 pages, 5178 KiB  
Article
Autoignition of Methane–Hydrogen Mixtures below 1000 K
by Vladimir Arutyunov, Andrey Belyaev, Artem Arutyunov, Kirill Troshin and Aleksey Nikitin
Processes 2022, 10(11), 2177; https://doi.org/10.3390/pr10112177 - 24 Oct 2022
Cited by 15 | Viewed by 2974
Abstract
In the range of 800–1200 K, both experiments and kinetic modeling demonstrate a significant difference in the dependence of the ignition delay time of methane and hydrogen on pressure and temperature, with the complex influence of these parameters on the autoignition delay time [...] Read more.
In the range of 800–1200 K, both experiments and kinetic modeling demonstrate a significant difference in the dependence of the ignition delay time of methane and hydrogen on pressure and temperature, with the complex influence of these parameters on the autoignition delay time of methane–hydrogen–air mixtures. In connection with the prospects for the widespread use of methane–hydrogen mixtures in energy production and transport, a detailed analysis of their ignition at temperatures below 1000 K, the most important region from the point of view of their practical application, is carried out. It is shown that such a complex behavior is associated with the transition in this temperature range from low-temperature mechanisms of oxidation of both methane and hydrogen, in which peroxide radicals and molecules play a decisive role, to high-temperature mechanisms of their oxidation, in which simpler radicals dominate. A kinetic interpretation of the processes occurring in this case is proposed. Full article
(This article belongs to the Special Issue Methane Reforming Processes)
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19 pages, 2135 KiB  
Article
Separation of Molar Weight-Distributed Polyethylene Glycols by Reversed-Phase Chromatography—Analysis and Modeling Based on Isocratic Analytical-Scale Investigations
by Malvina Supper, Kathleen Heller, Jakob Söllner, Tuomo Sainio and Malte Kaspereit
Processes 2022, 10(11), 2160; https://doi.org/10.3390/pr10112160 - 22 Oct 2022
Cited by 4 | Viewed by 3188
Abstract
The separation of polyethylene glycols (PEGs) into single homologs by reversed-phase chromatography is investigated experimentally and theoretically. The used core–shell column is shown to achieve the baseline separation of PEG homologs up to molar weights of at least 5000 g/mol. A detailed study [...] Read more.
The separation of polyethylene glycols (PEGs) into single homologs by reversed-phase chromatography is investigated experimentally and theoretically. The used core–shell column is shown to achieve the baseline separation of PEG homologs up to molar weights of at least 5000 g/mol. A detailed study is performed elucidating the role of the operating conditions, including the temperature, eluent composition, and degree of polymerization of the polymer. Applying Martin’s rule yields a simple model for retention times that holds for a wide range of conditions. In combination with relations for column efficiency, the role of the operating conditions is discussed, and separations are predicted for analytical-scale chromatography. Finally, the approach is included in an efficient process model based on discrete convolution, which is demonstrated to predict with high accuracy also advanced operating modes with arbitrary injection profiles. Full article
(This article belongs to the Special Issue Advances in Green Chemistry Analytical Techniques)
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24 pages, 5323 KiB  
Article
Preliminary Experimental Results and Modelling Study of Olive Kernel Gasification in a 2 MWth BFB Gasifier
by Athanasios Lampropoulos, Idoya Goñi Zubillaga, Raúl Pérez-Vega, Nikolaos Ntavos, Yannis Fallas and Georgios Varvoutis
Processes 2022, 10(10), 2020; https://doi.org/10.3390/pr10102020 - 7 Oct 2022
Cited by 3 | Viewed by 2506
Abstract
Gasification is a promising and attractive thermochemical method for biomass-to-energy conversion, with fluidized bed reactors being one of the best options for large-scale operations. Olive residues in particular are potentially excellent candidate biomass fuels in the Mediterranean area, due to the region’s increased [...] Read more.
Gasification is a promising and attractive thermochemical method for biomass-to-energy conversion, with fluidized bed reactors being one of the best options for large-scale operations. Olive residues in particular are potentially excellent candidate biomass fuels in the Mediterranean area, due to the region’s increased capacity in olive oil production. Herein, the gasification experiments of olive kernels in a 2 MWth air-blown, bubbling fluidized bed reactor located at CENER’s facilities (BIO2C) in Navarra, Spain are presented. Even though technical issues were demonstrated due to the operation of the plant with a high-density biomass fuel and given the scale of the process, a quasi-steady-state and isothermal 12 h operation at an equivalence ratio of 0.25 ± 0.03 was attained. Given the satisfactory experimental results, an Aspen Plus simulation model of the process was also attempted. Notably, the proposed methodology agrees well with the experimental results and can be regarded as a starting point in future studies examining the gasification of relevant biomass in a MW-scale unit. Next, the effect of equivalence ratio and residual biomass moisture content were also evaluated, with the scope of designing future experiments that require minor modifications in the already existing apparatus. Finally, a syngas utilization route through the provision of energy for district heating purposes in the nearby village of Aoiz was proposed. Full article
(This article belongs to the Special Issue Gas Emissions Control and Utilization)
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12 pages, 3428 KiB  
Article
Modelling for the Efficient Effluent Dye Removal to Reuse Water and Salt
by Valentina Buscio, Víctor López-Grimau, Bettina Vallés, Montserrat Pepió and Carmen Gutiérrez-Bouzán
Processes 2022, 10(10), 2024; https://doi.org/10.3390/pr10102024 - 7 Oct 2022
Cited by 2 | Viewed by 1601
Abstract
The objective of this work was to determine the optimal conditions for the electrooxidation treatment in order to decolourise the effluents that contain reactive dyes. According to the results, when Na2SO4 is used as an electrolyte, the decolouration reactions follow [...] Read more.
The objective of this work was to determine the optimal conditions for the electrooxidation treatment in order to decolourise the effluents that contain reactive dyes. According to the results, when Na2SO4 is used as an electrolyte, the decolouration reactions follow first-order kinetics. However, when NaCl is present in the effluent, the first-order kinetics is stabilised after applying a minimal electric current value. The models obtained from the results show that the higher the concentration of NaCl, the lower the energy consumption. On the other hand, an increase in dye concentration leads to an increase in electrical consumption. In relation to the pH, the results show that it is not a key factor in the decolouration efficiency. Finally, the obtained model was applied to two real effluents. The feasibility of individually treating the effluents from the dyeing process and those from the subsequent wash-off process was evaluated. From an industrial application point of view, it is recommended to mix both effluents before treatment, especially when the dye concentration is high. Full article
(This article belongs to the Special Issue Resource Recovery and Harmless Treatment Processes for Industrial Organic Pollutants)
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13 pages, 6272 KiB  
Article
Optimizing the Geometric Parameters of a Stepped Labyrinth Seal to Minimize the Discharge Coefficient
by Ye Hwan Chun and Joon Ahn
Processes 2022, 10(10), 2019; https://doi.org/10.3390/pr10102019 - 6 Oct 2022
Cited by 9 | Viewed by 2837
Abstract
A series of numerical simulations were performed to study the discharge coefficient based on the geometric parameters of a stepped labyrinth seal that sealed the secondary flow path of a gas turbine. In contrast with straight-through seals, stepped labyrinth seals introduce additional geometrical [...] Read more.
A series of numerical simulations were performed to study the discharge coefficient based on the geometric parameters of a stepped labyrinth seal that sealed the secondary flow path of a gas turbine. In contrast with straight-through seals, stepped labyrinth seals introduce additional geometrical parameters related to the steps. In this study, three shape variables were observed: step height (SH), position, and cavity width (CW). The sensitivity to the leakage flow of the shape variable in the stepped labyrinth seal was analyzed. The mechanism for improving the sealing performance of stepped labyrinth seals was investigated. The results indicated that the stepped labyrinth seal exhibited up to 17.9% higher leakage-suppression performance than the straight labyrinth seal. Seals with large discharge coefficients had a large vena contracta upstream of each tooth structure and a rapidly accelerated axial velocity in the radial direction. We could observe that the discharge coefficient changed according to the flow field in the cavity. The wall shear stress was sensitive to the SH but not to the CW or step position. Full article
(This article belongs to the Section Manufacturing Processes and Systems)
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13 pages, 4876 KiB  
Article
Hybrid Methodology Based on Symmetrized Dot Pattern and Convolutional Neural Networks for Fault Diagnosis of Power Cables
by Meng-Hui Wang, Hong-Wei Sian and Shiue-Der Lu
Processes 2022, 10(10), 2009; https://doi.org/10.3390/pr10102009 - 5 Oct 2022
Cited by 3 | Viewed by 3150
Abstract
This study proposes a recognition method based on symmetrized dot pattern (SDP) analysis and convolutional neural network (CNN) for rapid and accurate diagnosis of insulation defect problems by detecting the partial discharge (PD) signals of XLPE power cables. First, a normal and three [...] Read more.
This study proposes a recognition method based on symmetrized dot pattern (SDP) analysis and convolutional neural network (CNN) for rapid and accurate diagnosis of insulation defect problems by detecting the partial discharge (PD) signals of XLPE power cables. First, a normal and three power cable models with different insulation defects are built. The PD signals resulting from power cable insulation defects are measured. The frequency and amplitude variations of PD signals from different defects are reflected by comprehensible images using the proposed SDP analysis method. The features of different power cable defects are presented. Finally, the feature image is trained and identified by CNN to achieve a power cable insulation fault diagnosis system. The experimental results show that the proposed method could accurately diagnose the fault types of power cable insulation defects with a recognition accuracy of 98%. The proposed method is characterized by a short detection time and high diagnostic accuracy. It can effectively detect the power cable PD to identify the fault type of the insulation defect. Full article
(This article belongs to the Section Energy Systems)
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10 pages, 1727 KiB  
Article
Physical and Chemical Regularities of Phosphorus and Beryllium Recovery by the Sorbents Based on Acrylic Fiber Impregnated by Iron Hydroxide (III)
by Nikolay A. Bezhin, Mariya A. Frolova, Ol’ga N. Kozlovskaia, Evgeniy V. Slizchenko, Iuliia G. Shibetskaia and Ivan G. Tananaev
Processes 2022, 10(10), 2010; https://doi.org/10.3390/pr10102010 - 5 Oct 2022
Cited by 8 | Viewed by 1701
Abstract
The paper investigates the physicochemical regularities (kinetics and isotherm) of phosphorus and beryllium recovery by sorbents based on polyacrylonitrile (PAN) fiber and Fe(OH)3 obtained by various methods: PAN or pre-hydrolyzed PAN with precipitation of FeCl3 with ammonia, using ready-made or electrochemically [...] Read more.
The paper investigates the physicochemical regularities (kinetics and isotherm) of phosphorus and beryllium recovery by sorbents based on polyacrylonitrile (PAN) fiber and Fe(OH)3 obtained by various methods: PAN or pre-hydrolyzed PAN with precipitation of FeCl3 with ammonia, using ready-made or electrochemically generated Na2FeO4, pre-hydrolyzed PAN treated with an alkaline solution of Na2FeO4, as well as their comparison with granular aluminum oxide. The Langmuir, Freudlich and Dubinin–Radushkevich models show high performance of materials for sorption of stable P and Be used as tracers for the release of 7Be, 32P, and 33P from seawater. The obtained kinetic data are processed using kinetic models of intraparticle diffusion and the pseudo-first-order, pseudo-second-order, and Elovich models. Optimal conditions for obtaining sorbents are established, namely, the effect of NaOH concentration at the stages of preparation on the properties of sorbents based on the PAN fiber and Fe(OH)3 obtained by various methods. Full article
(This article belongs to the Special Issue Resource Recovery and Harmless Treatment Processes for Industrial Organic Pollutants)
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16 pages, 3243 KiB  
Article
Towards Autonomous Process Control—Digital Twin for HIV-Gag VLP Production in HEK293 Cells Using a Dynamic Metabolic Model
by Heribert Helgers, Alina Hengelbrock, Jamila Franca Rosengarten, Jörn Stitz, Axel Schmidt and Jochen Strube
Processes 2022, 10(10), 2015; https://doi.org/10.3390/pr10102015 - 5 Oct 2022
Cited by 7 | Viewed by 2395
Abstract
Despite intensive research over the last three decades, it has not yet been possible to bring an effective vaccine against human immunodeficiency virus (HIV) and the resulting acquired immunodeficiency syndrome (AIDS) to market. Virus-like particles (VLP) are a promising approach for efficient and [...] Read more.
Despite intensive research over the last three decades, it has not yet been possible to bring an effective vaccine against human immunodeficiency virus (HIV) and the resulting acquired immunodeficiency syndrome (AIDS) to market. Virus-like particles (VLP) are a promising approach for efficient and effective vaccination and could play an important role in the fight against HIV. For example, HEK293 (human embryo kidney) cells can be used to produce virus-like particles. In this context, given the quality-by-design (QbD) concept for manufacturing, a digital twin is of great importance for the production of HIV-Gag-formed VLPs. In this work, a dynamic metabolic model for the production of HIV-Gag VLPs was developed and validated. The model can represent the VLP production as well as the consumption or formation of all important substrates and metabolites. Thus, in combination with already described process analytical technology (PAT) methods, the final step towards the implementation of a digital twin for process development and design, as well as process automation, was completed. Full article
(This article belongs to the Special Issue Towards Autonomous Operation of Biologics and Botanicals)
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13 pages, 953 KiB  
Review
Valorization of Lignin and Its Derivatives Using Yeast
by Filemon Jalu Nusantara Putra, Prihardi Kahar, Akihiko Kondo and Chiaki Ogino
Processes 2022, 10(10), 2004; https://doi.org/10.3390/pr10102004 - 4 Oct 2022
Cited by 10 | Viewed by 3621
Abstract
As the third most plentiful biopolymer after other lignocellulosic derivates such as cellulose and hemicellulose, lignin carries abundant potential as a substitute for petroleum-based products. However, the efficient, practical, value-added product valorization of lignin remains quite challenging. Although several studies have reviewed the [...] Read more.
As the third most plentiful biopolymer after other lignocellulosic derivates such as cellulose and hemicellulose, lignin carries abundant potential as a substitute for petroleum-based products. However, the efficient, practical, value-added product valorization of lignin remains quite challenging. Although several studies have reviewed the valorization of lignin by microorganisms, this present review covers recent studies on the valorization of lignin by employing yeast to obtain products such as single-cell oils (SCOs), enzymes, and other chemical compounds. The use of yeasts has been found to be suitable for the biological conversion of lignin and might provide new insights for future research to develop a yeast strain for lignin to produce other valuable chemical compounds. Full article
(This article belongs to the Special Issue Application of Advanced Synthetic Biological Approaches in Microbial Platforms)
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11 pages, 2668 KiB  
Article
Effects of Calcium Sulfate and Chitosan on Textural Modification and Microstructure of Tofu Made from Lentils (Lens culinaris)
by Cheng-Hsun Jao, Chieh-Yi Lin, Chao-Jung Chen and Jung-Feng Hsieh
Processes 2022, 10(10), 2000; https://doi.org/10.3390/pr10102000 - 3 Oct 2022
Cited by 5 | Viewed by 3101
Abstract
This study investigated calcium sulfate and chitosan on the textural modification and microstructure of tofu made from lentils. The addition of varying amounts of calcium sulfate (0–12 mM) and chitosan (0–1.0%) into lentil milk could affect the gel properties of lentil-based tofu. The [...] Read more.
This study investigated calcium sulfate and chitosan on the textural modification and microstructure of tofu made from lentils. The addition of varying amounts of calcium sulfate (0–12 mM) and chitosan (0–1.0%) into lentil milk could affect the gel properties of lentil-based tofu. The gel properties, including the hardness and cohesiveness, of lentil-based tofu significantly increased with the addition of 12 mM calcium sulfate, exhibiting a slightly discontinuous network structure and a slightly regular pore network. However, the gel properties including hardness and cohesiveness significantly decreased with the addition of 1.0% chitosan, presenting a slightly continuous network structure with pores. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that the aggregation of the vicilin, legumin acidic unit and legumin basic unit proteins in lentil milk was induced both by 12 mM calcium sulfate and 1.0% chitosan. Our results suggested that calcium sulfate and chitosan could affect the gel properties, such as hardness and cohesiveness, of lentil-based tofu. Therefore, calcium sulfate and chitosan can be used as practical food additives for the development of texture-modified lentil-based tofu. Full article
(This article belongs to the Special Issue Food Processing and Food Analysis: Principles, Techniques, and Applications)
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17 pages, 1963 KiB  
Article
Physicochemical Analysis of Cold Brew and Hot Brew Peaberry Coffee
by Evan T. Schwarzmann, Marlena P. Washington and Niny Z. Rao
Processes 2022, 10(10), 1989; https://doi.org/10.3390/pr10101989 - 2 Oct 2022
Cited by 6 | Viewed by 3428
Abstract
Peaberry coffee is the result of a natural mutation of coffee beans, and they make up only about 5–7% of coffee crops. A typical coffee cherry contains two seeds that are developed against each other, resulting in the distinctive half-rounded shape of coffee [...] Read more.
Peaberry coffee is the result of a natural mutation of coffee beans, and they make up only about 5–7% of coffee crops. A typical coffee cherry contains two seeds that are developed against each other, resulting in the distinctive half-rounded shape of coffee beans. However, failing to fertilize both ovules of one of the seeds or failure in endosperm development can cause only one of the seeds to develop, resulting in smaller, denser beans with a more domed shape. Peaberry coffees are said to be sweeter, lighter, and more flavorful since the peaberry beans receive all nutrients from the coffee cherry. Due to its exclusive nature, the chemical characteristic of peaberry coffee is not well understood. This study explores the acidities and antioxidant activity of peaberry coffee sourced from multiple regions. Total antioxidant capacity, total caffeoylquinic acid (CQA), total caffeine concentration, and pH levels were evaluated for peaberry coffee extracts prepared by cold and hot brewing methods. Little correlation between antioxidant activity and the concentrations of caffeine and CQA in peaberry beans was shown. Six methods were performed for the characterization of total antioxidant capacity including cyclic voltammetry, ABTS assay, and FRAP assay. Peaberry bean extract demonstrated higher average total caffeine concentrations compared to traditional coffee bean extracts. Full article
(This article belongs to the Special Issue Total Antioxidant Capacity: Idea, Methods and Limitations)
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19 pages, 2329 KiB  
Article
Chemical Vapor Deposition of Longitudinal Homogeneous Parylene Thin-Films inside Narrow Tubes
by David Redka, Milan Buttberg and Gerhard Franz
Processes 2022, 10(10), 1982; https://doi.org/10.3390/pr10101982 - 1 Oct 2022
Cited by 2 | Viewed by 2469
Abstract
The effect of quasi-exponentially decreasing film thicknesses of thin poly-para-xylylene (PPX-N) coatings inside narrow tubes or micro scaled gaps is well known and has been discussed by many authors since the late 1970s. However, for technical applications it is often necessary [...] Read more.
The effect of quasi-exponentially decreasing film thicknesses of thin poly-para-xylylene (PPX-N) coatings inside narrow tubes or micro scaled gaps is well known and has been discussed by many authors since the late 1970s. However, for technical applications it is often necessary to provide a longitudinal homogeneous film thickness to ensure the constant properties that are required. In a previous work, it was shown, in principle and for the first time, that a temperature gradient along the tube will effectively counteract the longitudinal decreasing film thickness of the PPX-N coating of the interior wall of a capillary. Therefore, this effect is discussed in theory and the provided model is verified by experiments. Our prediction of a required sticking coefficient curve yields experimentally measured homogeneous film thicknesses and shows a good agreement with the given prognosis. Further, it is shown in theory that there is a maximum achievable homogeneous film thickness in the tube in comparison to a blank surface, which can be understood as a coating efficiency for this type of deposition. Full article
(This article belongs to the Special Issue Design and Optimization in Process Engineering)
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15 pages, 2755 KiB  
Article
Custom-Shaped Carbon Xerogel Materials by 3D Printing
by Cédric Wolfs, Stéphanie D. Lambert, Alexandre F. Léonard and Julien G. Mahy
Processes 2022, 10(10), 1979; https://doi.org/10.3390/pr10101979 - 1 Oct 2022
Cited by 2 | Viewed by 2125
Abstract
Sol–gel-based carbon xerogels possess very promising properties for pollution abatement, using processes that associate adsorption and on-site electrochemical oxidation. However, combining a high exterior surface area (for efficient diffusion) and a monolithic shape (necessary for electrochemical processes) poses challenges. In this work, the [...] Read more.
Sol–gel-based carbon xerogels possess very promising properties for pollution abatement, using processes that associate adsorption and on-site electrochemical oxidation. However, combining a high exterior surface area (for efficient diffusion) and a monolithic shape (necessary for electrochemical processes) poses challenges. In this work, the shape of monolithic carbon xerogels was contrived by the use of 3D-printed molds. Several parameters were optimized: the choice of mold design, the choice of plastic, the 3D printer parameters, the solvent, and the process of dissolving the plastic. A design combining fine sticks and plates made of ABS was printed; a sol–gel carbon xerogel monolith was synthesized in it, and the mold was removed by using a combination of acetone and pyrolysis. Dissolving the plastic could be carried out by placing the material on a metallic net and leaving the dissolved ABS to settle. The resulting carbon material exhibits a high exterior surface area and good strength, leading to potential uses in the aforementioned process. The research shows that 3D printing is an efficient method of parameter optimization in pre-industrialization research, thanks to its flexibility, low cost, and ease of use. Full article
(This article belongs to the Special Issue Advances in Sol-Gel Processes)
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10 pages, 781 KiB  
Article
The Mercury Concentration in Spice Plants
by Agnieszka Fischer and Barbara Brodziak-Dopierała
Processes 2022, 10(10), 1954; https://doi.org/10.3390/pr10101954 - 28 Sep 2022
Cited by 1 | Viewed by 4036
Abstract
Spice plants are popularly used as ingredients in food products. Promoting healthy eating, paying attention to the quality of products, means that organic and self-produced ingredients, whose origin and growing conditions are known, are gaining popularity. The study determined the concentration of mercury [...] Read more.
Spice plants are popularly used as ingredients in food products. Promoting healthy eating, paying attention to the quality of products, means that organic and self-produced ingredients, whose origin and growing conditions are known, are gaining popularity. The study determined the concentration of mercury (Hg) in popular leafy spice plants: peppermint (Mentha piperita), common basil (Ocimum basilicum), lovage (Levisticum officinale) and parsley (Petroselinum crispum). Self-grown spices and ready-made commercial products were selected for the study. The Hg content in the test samples was determined by the AAS method (AMA 254, Altec, Praha, Czech Republic). The range of Hg content in the tested spice samples ranged from 1.20 to 17.35 µg/kg, on average 6.95 µgHg/kg. The highest concentration of Hg was recorded in the peppermint, 9.39 µg/kg. In plants grown independently, the concentration of Hg was statistically significantly higher than in commercial products purchased in a store. There were no differences in the concentration of Hg in organic and non-organic spices. Commercial spices defined by producers as organic products did not differ statistically significantly in the level of Hg content from non-organic products. Full article
(This article belongs to the Special Issue 10th Anniversary of Processes: Women's Special Issue Series)
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14 pages, 2530 KiB  
Article
The Efficacy of Plant Enzymes Bromelain and Papain as a Tool for Reducing Gluten Immunogenicity from Wheat Bran
by Vijole Bradauskiene, Lina Vaiciulyte-Funk, Darius Cernauskas, Reda Dzingeleviciene, Joao P. M. Lima, Aida Bradauskaite and Mihaela Adriana Tita
Processes 2022, 10(10), 1948; https://doi.org/10.3390/pr10101948 - 27 Sep 2022
Cited by 8 | Viewed by 8995
Abstract
Gluten-free products made from naturally gluten-free raw materials have an inferior taste and can cause deficiencies in various nutrients, especially non-starch polysaccharides. To address this problem, scientists are searching for new strategies to eliminate harmful gluten from wheat, rye, and barley and to [...] Read more.
Gluten-free products made from naturally gluten-free raw materials have an inferior taste and can cause deficiencies in various nutrients, especially non-starch polysaccharides. To address this problem, scientists are searching for new strategies to eliminate harmful gluten from wheat, rye, and barley and to produce balanced products with good organoleptic properties. This study evaluated the possibility of hydrolysing gluten in wheat bran, a by-product obtained after the dry fractionation of wheat, using plant enzymes. The gluten content of wheat bran after treatment with papain, bromelain, and their combination under different hydrolysis conditions was investigated. The amount of gluten was determined using an enzyme-linked immunosorbent assay ELISA R5 and the reduction in immunogenic gliadins was analysed using high-performance reverse phase liquid chromatography. The results of the study showed that 4 h hydrolysis with bromelain and papain reduced the levels of gluten immunogenic compounds in bran from 58,650.00 to 2588.20–3544.50 mg/kg; however, they did not reach the gluten-free limit. A higher hydrolysis efficiency of 95.59% was observed after treatment with papain, while the combination of both enzymes and bromelain alone were less effective. The results presented in this article will be helpful to other researchers and manufacturers of wheat-based products when selecting methods to reduce gluten immunogenicity and contribute to the development of sustainable technologies. Full article
(This article belongs to the Special Issue Applications of Structural Biology Techniques in Enzymology)
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22 pages, 10059 KiB  
Article
Analysis of Gas Flow Dynamics in Thermal Cut Kerf Using a Numerical and Experimental Approach for Nozzle Selection
by Upendra Tuladhar, Sang-Hyun Ahn, Dae-Won Cho, Dae-Hwan Kim, Seokyoung Ahn, Seonmin Kim, Seung-Hoon Bae and Tae-Kook Park
Processes 2022, 10(10), 1951; https://doi.org/10.3390/pr10101951 - 27 Sep 2022
Cited by 5 | Viewed by 2195
Abstract
Consistency in gas flow behavior under various operating conditions is expected for uniform cutting performance in the thermal cutting process. The slope of the cut front in the kerf slot of a sample cutting material varies with the operating condition which affects the [...] Read more.
Consistency in gas flow behavior under various operating conditions is expected for uniform cutting performance in the thermal cutting process. The slope of the cut front in the kerf slot of a sample cutting material varies with the operating condition which affects the gas flow pattern. Therefore, how the nozzle exit diameter and the slope of the cut front effects gas flow behavior has been studied using the Reynolds averaged Navier–Stokes (RANS) based k–ω turbulence model. Convergent–straight-type nozzles with exit diameters φexit of 1.5 mm, 2 mm and 2.5 mm were used to study the flow patterns through the kerf slots of variable cut front slopes. The numerical simulation results were then compared with the results obtained from the Schlieren experiments. In addition, image processing was performed in the Schlieren images for clear visualization and precise comparison of the numerical and experimental data. The results confirm that a nozzle with an exit diameter of 2 mm shows a higher consistency in flow behavior in variable operating conditions. Full article
(This article belongs to the Collection Modeling, Simulation and Computation on Dynamics of Complex Fluids)
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10 pages, 524 KiB  
Article
Application of High Pressure Processing on Ultrasonically Treated Extract from Wild Bitter Gourd
by Chang-Yi Huang and Su-Der Chen
Processes 2022, 10(10), 1926; https://doi.org/10.3390/pr10101926 - 23 Sep 2022
Cited by 3 | Viewed by 2032
Abstract
Wild bitter gourd extracts, such as saponins, polysaccharides, and peptides, could be used to adjust blood sugar. The objective of this research was to explore the use of high pressure processing (HPP) for sterilization and acceleration of enzyme hydrolysis in the ultrasonic preparation [...] Read more.
Wild bitter gourd extracts, such as saponins, polysaccharides, and peptides, could be used to adjust blood sugar. The objective of this research was to explore the use of high pressure processing (HPP) for sterilization and acceleration of enzyme hydrolysis in the ultrasonic preparation of peptide extracts from wild bitter gourd. The results showed that the wild bitter gourd powder could be extracted via ultrasonic processing with water at 70 °C for only 20 min with a solid to liquid ratio of 1:20 to obtain the total protein content of 1.514 mg/g. The two sterilization methods for wild bitter gourd extract treated with papaya enzyme—for 2 h in the traditional autoclave at 121 °C for 15 min, or under HPP 300 MPa for 5 min—showed no significant effect on protein content, and both sterilization methods were effective. However, the extract sterilized with HPP had a significantly higher ability to scavenge DPPH free radicals. In addition, HPP (300 MPa for 5 min), combined with papaya enzyme to hydrolyze the wild bitter gourd extract, simultaneously pasteurized the extract and acquired the peptides from the wild bitter gourd extract Therefore, the ultrasonic extraction of wild bitter gourd, combined with HPP and enzyme hydrolysis, could greatly shorten the operation time (to only 5 min) for extracting the active peptides. Full article
(This article belongs to the Special Issue Agriculture Products Processing and Storage)
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11 pages, 2603 KiB  
Communication
Application of the Analogy between Momentum and Heat Flux in Turbulent Flow of a Straight Tube to a Spiral Tube
by Kye-Bock Lee, Eui-Hyeok Song, Ji-Su Lee and Seok-Ho Rhi
Processes 2022, 10(10), 1927; https://doi.org/10.3390/pr10101927 - 23 Sep 2022
Cited by 2 | Viewed by 2696
Abstract
A theory-based prediction method was used to estimate the friction factor and heat transfer rate in the turbulent flow of a helically coiled tube. The secondary flow produced by a centrifugal force improves heat and mass transfer; therefore, spiral coil pipes are widely [...] Read more.
A theory-based prediction method was used to estimate the friction factor and heat transfer rate in the turbulent flow of a helically coiled tube. The secondary flow produced by a centrifugal force improves heat and mass transfer; therefore, spiral coil pipes are widely used in a variety of industrial applications. The law of the wall and the Reynolds analogy, which states that momentum transfer in a turbulent flow is equivalent to heat transfer, were used in this theoretical method. The logarithmic law was used to characterize the velocity profile in the turbulence-dominated region, and the local wall shear stress variation throughout the circumference of the helical tube wall was considered. The friction factor and heat transfer in the turbulent flow of the helically coiled tube were accurately predicted by the model. Using the Reynolds analogy, the local Nusselt number in the circumferential direction of the helical tube wall was determined. The effect of decreasing local heat transfer within the tube while increasing heat transfer outside the tube was quantified. The analogy between the momentum flux and the heat flux in the turbulent flow of the straight tube was also proven to be applicable to the spiral tube. Full article
(This article belongs to the Special Issue Complex Fluid Dynamics Modeling and Simulation)
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16 pages, 5322 KiB  
Article
Large Eddy Simulation of Conjugate Heat Transfer in a Ribbed Channel: Reynolds Number Effect
by Joon Ahn, Jeong Chul Song and Joon Sik Lee
Processes 2022, 10(10), 1928; https://doi.org/10.3390/pr10101928 - 23 Sep 2022
Cited by 3 | Viewed by 2193
Abstract
Large eddy simulations were performed for the conjugate heat transfer in a ribbed channel with a geometry, that mimics the internal cooling passage of a gas turbine, using 566, 100, 10, and 1 as the solid and fluid thermal conductivity ratios (K [...] Read more.
Large eddy simulations were performed for the conjugate heat transfer in a ribbed channel with a geometry, that mimics the internal cooling passage of a gas turbine, using 566, 100, 10, and 1 as the solid and fluid thermal conductivity ratios (K*) and 30,000, 7000 (turbulent flow), and 1000 (laminar flow) as the Reynolds numbers. A fully coupled simulation was conducted using the immersed boundary method (IBM) and a dynamic sub-grid-scale (SGS) model. In pure convection, a decrease in the Reynolds number from 30,000 to 7000 increased the heat transfer on the channel wall by 5% but decreased that on the rib by 20%. When K* > 10, the Reynolds number effect is stronger in the rib than in the wall. In the laminar flow, the effect of conduction appears at a low K*, and the heat transfer promotion is poor in the typical ribbed channel geometry. In the turbulent flow, if K* ≥ 100, then a heat transfer promotion is expected in the ribbed channel even at a low Reynolds number. For K* < 10, the thermal performance in the turbulent flow is worse than that in the laminar flow, and thus, no rib effect is expected. Full article
(This article belongs to the Special Issue CFD Based Researches and Applications for Fluid Machinery and Fluid Device, Volume II)
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14 pages, 2868 KiB  
Article
To the Theory of Grain Motion in an Uneven Air Flow in a Vertical Pneumatic Separation Channel with an Annular Cross Section
by Serhii Stepanenko, Borys Kotov, Alvian Kuzmych, Viktor Shvydia, Roman Kalinichenko, Serhii Kharchenko, Taras Shchur, Sławomir Kocira, Dariusz Kwaśniewski and Dariusz Dziki
Processes 2022, 10(10), 1929; https://doi.org/10.3390/pr10101929 - 23 Sep 2022
Cited by 9 | Viewed by 2429
Abstract
The possibilities of the action of uneven air flows on the grain material in the separating channels are still not used enough. The reason for this is the insufficient knowledge of the processes of interaction of the components of the grain material with [...] Read more.
The possibilities of the action of uneven air flows on the grain material in the separating channels are still not used enough. The reason for this is the insufficient knowledge of the processes of interaction of the components of the grain material with an uneven air flow. The purpose of the research is to increase the efficiency of grain material separation according to aerodynamic properties by purposefully changing the diagram of air velocities in the channel sections using the actions of lateral and aerodynamic forces. The separation efficiency of grain material components was determined by trajectory analysis. The different geometry of the pneumatic separation channel was studied. The study of the distribution of air velocity and air pressure vectors in a vertical annular channel was carried out using the FlowVision software. It has been established that a change in the air velocity diagram can be implemented both by changing the geometric parameters of the channel and by additional distributed air supply through the perforation in the side walls of the pneumatic channel. Based on the analysis of the velocity field, an improved scheme of a pneumatic gravitational separator is proposed for separating grain material into three fractions according to aerodynamic characteristics. Full article
(This article belongs to the Special Issue Progress in Food Processing)
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18 pages, 6119 KiB  
Article
A Hybrid Fault Diagnosis Approach Using FEM Optimized Sensor Positioning and Machine Learning
by Sang Jin Jung, Tanvir Alam Shifat and Jang-Wook Hur
Processes 2022, 10(10), 1919; https://doi.org/10.3390/pr10101919 - 22 Sep 2022
Viewed by 1888
Abstract
Sensor acquired signal has been a fundamental measure in rotary machinery condition monitoring (CM) to enhance system reliability and stability. Inappropriate sensor mounting can lead to loss of fault-related information and generate false alarms in industrial systems. To ensure reliable system operation, in [...] Read more.
Sensor acquired signal has been a fundamental measure in rotary machinery condition monitoring (CM) to enhance system reliability and stability. Inappropriate sensor mounting can lead to loss of fault-related information and generate false alarms in industrial systems. To ensure reliable system operation, in this paper we investigate a system’s multiple degrees-of-freedom (DOF) using the finite element method (FEM) to find the optimum sensor mounting position. An appropriate sensor position is obtained by the highest degree of deformation in FEM modal analysis. The effectiveness of the proper sensor mounting position was compared with two other sensor mounting points, which were selected arbitrarily. To validate the effectiveness of this method we considered a gear-actuator test bench, where the sensors were mounted in the same place as the FEM simulation. Vibration data were acquired through these sensors for different health states of the system and failure patterns were recognized using an artificial neural network (ANN) model. An ANN model shows that the optimum sensor mounting point found in FEM has the highest accuracy, compared to other mounting points. A hybrid CM framework, combining the physics-based and data-driven approaches, provides robust fault detection and identification analysis of the gear-actuator system. Full article
(This article belongs to the Special Issue Intelligent Control Theory and Applications in Process Optimization and Smart Manufacturing)
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14 pages, 1743 KiB  
Article
Downstream Torrefaction of Wood Pellets in a Rotary Kiln Reactor—Impact on Solid Biofuel Properties and Torr-Gas Quality
by Özge Mutlu, Poulami Roy and Thomas Zeng
Processes 2022, 10(10), 1912; https://doi.org/10.3390/pr10101912 - 21 Sep 2022
Cited by 6 | Viewed by 3002
Abstract
Solid biofuels produced from torrefaction have improved coal-like properties in comparison to raw biofuels, yet ensuring uniform product quality is still a challenge. In this study, downstream torrefaction of wood pellets was performed at temperatures between 200 and 270 °C in a rotary [...] Read more.
Solid biofuels produced from torrefaction have improved coal-like properties in comparison to raw biofuels, yet ensuring uniform product quality is still a challenge. In this study, downstream torrefaction of wood pellets was performed at temperatures between 200 and 270 °C in a rotary kiln reactor to understand the effect of torrefaction temperature on product quality. The torrefied solid biofuel was compared with dedicated fuel properties defined in ISO/TS 17225-8:2016-12. Based on the results, the optimal temperature for downstream torrefaction was found at temperatures of 230 and 250 °C. Above this temperature, the effect of bulk density superimposes not only the increased net calorific value but also values for mechanical durability, amount of fines, and bulk density of the solid biofuel, which were below the thresholds of the fuel standard. Moreover, increasing process temperatures caused higher heavy metal concentrations in torrefied pellets. The composition of condensable and non-condensable fractions of the torr-gas substantially increased between temperatures of 230 and 250 °C and remained on a similar level at higher temperatures. Thus, the utilization of torr-gas for energy recovery purposes and as a precursor for the recovery of valuable chemicals should be balanced with the quality of the solid biofuel in the aforementioned range of torrefaction temperatures to enable the utilization of torrefaction products at further steps. Full article
(This article belongs to the Special Issue Biomass Torrefaction: Processes, Applications and Challenges)
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13 pages, 1890 KiB  
Article
Classification of Droplets of Water-PVP Solutions with Different Viscosity Values Using Artificial Neural Networks
by Mohamed Azouz Mrad, Kristof Csorba, Dorián László Galata and Zsombor Kristóf Nagy
Processes 2022, 10(9), 1780; https://doi.org/10.3390/pr10091780 - 5 Sep 2022
Cited by 2 | Viewed by 2044
Abstract
When a liquid flows, it has an internal resistance to flow. Viscosity is the property that measures this resistance, which is a fundamental characteristic parameter of liquids. The monitoring of viscosity is essential for quality control in many industrial areas, such as the [...] Read more.
When a liquid flows, it has an internal resistance to flow. Viscosity is the property that measures this resistance, which is a fundamental characteristic parameter of liquids. The monitoring of viscosity is essential for quality control in many industrial areas, such as the pharmaceutical, chemical, and energy-related industries. Several instruments measure the viscosity of a liquid, the most used being the capillary viscometers. These instruments are complex, associated with high cost and expensive prices. This represents a challenge in several industries, where accurate viscosity knowledge is essential in designing various industrial equipment and processes. Using image processing and machine learning algorithms is a promising alternative to the current measurement methods. This work aims to extract characteristic information from videos of droplets of different samples using image processing algorithms. An Artificial Neural Network model utilizes the extracted characteristics to classify the droplets in the correct category, which is correlated with the viscosity of the sample. Different solutions samples were created using different ratios of Water and PVP (Polyvinylpyrrolidone) and videos of their droplets were taken and processed. It was found that for water-PVP solutions, the proposed ANN model was able to successfully classify the droplets using the data extracted from the videos with high accuracy. The results imply that the ANN model can recognize the features that affect the viscosity values. Full article
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15 pages, 4776 KiB  
Article
Combined Biocidal Effect of Gaseous Ozone and Citric Acid on Acinetobacter baumannii Biofilm Formed on Ceramic Tiles and Polystyrene as a Novel Approach for Infection Prevention and Control
by Kaća Piletić, Bruno Kovač, Matej Planinić, Vanja Vasiljev, Irena Brčić Karačonji, Jure Žigon, Ivana Gobin and Martina Oder
Processes 2022, 10(9), 1788; https://doi.org/10.3390/pr10091788 - 5 Sep 2022
Cited by 8 | Viewed by 3310
Abstract
Acinetobacter baumannii is a prominent emerging pathogen responsible for a variety of hospital-acquired infections. It can contaminate inanimate surfaces and survive in harsh environmental conditions for prolonged periods of time in the form of biofilm. Biofilm is difficult to remove with only one [...] Read more.
Acinetobacter baumannii is a prominent emerging pathogen responsible for a variety of hospital-acquired infections. It can contaminate inanimate surfaces and survive in harsh environmental conditions for prolonged periods of time in the form of biofilm. Biofilm is difficult to remove with only one method of disinfection, so combined disinfection methods and biocidal active substances are needed for biofilm eradication. Additionally, having in mind ecological demands, legislators are more prone using fewer toxic substances for disinfection that produce less solid waste and hazardous disinfection byproducts. Gaseous ozone and citric acid are natural biocidal compounds, and the purpose of this study was to determine their combined biocidal effects on A. baumannii biofilm formed on ceramics and polystyrene. Twenty-four-hour A. baumannii biofilm formed on ceramic tiles and polystyrene was exposed to different combinations of disinfection protocols with 25 ppm of gaseous ozone for 1 h exposure time and 15% citric acid for 10 min exposure. The total number of bacteria was counted afterwards and expressed as CFU/cm2. The determined disinfection protocols of A. baumannii biofilm with combined citric acid and gaseous ozone caused reduction of 2.8 to 5.89 log10 CFU (99.99% inhibition rate) of total viable bacteria for each method, with the citric acid–ozone–citric acid disinfection protocol being most successful in eradication of viable bacteria on both ceramics and polystyrene. In conclusion, gaseous ozone and citric acid showed good combined biocidal effects on A. baumannii biofilm and successfully reduced early A. baumannii biofilm from ceramic and polystyrene surfaces. The given combination of active substances can be a good option for eco-friendly disinfection of hospital inanimate surfaces from A. baumannii biofilm contamination with prior mechanical cleaning. Full article
(This article belongs to the Special Issue Sanitary and Environmental Engineering: Relevance and Concerns)
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