Processes

12 pages, 2936 KiB

Open AccessEditor’s ChoiceArticle

The Biological Effects of Ozone Gas on Soft and Hard Dental Tissues and the Impact on Human Gingival Fibroblasts and Gingival Keratinocytes

by Alin Daniel Floare, Alexandra Denisa Scurtu, Octavia Iulia Balean, Doina Chioran, Roxana Buzatu, Ruxandra Sava Rosianu, Vlad Tiberiu Alexa, Daniela Jumanca, Laura-Cristina Rusu, Robert Cosmin Racea, Dorina Coricovac, Iulia Pinzaru, Cristina Adriana Dehelean and Atena Galuscan

Processes 2021, 9(11), 1978; https://doi.org/10.3390/pr9111978 - 5 Nov 2021

Cited by 5 | Viewed by 2880

Abstract

Ozone is an allotropic form of oxygen, so in the medical field ozone therapy has special effects. Starting from the premise that bio-oxidative ozone therapy reduces the number of bacteria, in the present study two approaches were proposed: to evaluate the biological effects [...] Read more.

Ozone is an allotropic form of oxygen, so in the medical field ozone therapy has special effects. Starting from the premise that bio-oxidative ozone therapy reduces the number of bacteria, in the present study two approaches were proposed: to evaluate the biological effects of ozone gas on the tooth enamel remineralization process and to demonstrate its impact on the morphology and confluence of human primary gingival cells, namely keratinocytes (PGK) and fibroblasts (HGF). The ozone produced by HealOzone was applied in vivo to 68 M1s (first permanent molars), both maxillary and mandibular, on the occlusal surfaces at pit and fissure. The molars included in the study recorded values between 13 and 24 according to the DIAGNOdent Pen 2190 scale, this being the main inclusion/exclusion criterion for the investigated molars. Because the gas can make contact with primary gingival cells during the ozonation process, both human gingival fibroblasts and keratinocytes were exposed to different doses of ozone (20 s, 40 s, 60 s), and its effects were observed with the Olympus IX73 inverted microscope. The contact of ozone with the human primary gingival cells demonstrates cell sensitivity to the action of ozone, this being higher in fibroblasts compared to keratinocytes, but it is not considered toxic because all the changes are reversible at 48 h after exposure. Full article

(This article belongs to the Special Issue Basic, Biological and Therapeutic Processes of Ozone Therapy)

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16 pages, 3368 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Highly Stable and Nontoxic Lanthanum-Treated Activated Palygorskite for the Removal of Lake Water Phosphorus

by Bhabananda Biswas and Ravi Naidu

Processes 2021, 9(11), 1960; https://doi.org/10.3390/pr9111960 - 2 Nov 2021

Cited by 3 | Viewed by 2197

Abstract

Nutrient pollution of surface water, such as excess phosphate loading on lake surface water, is a significant issue that causes ecological and financial damage. Despite many technologies that can remove available phosphate, such as material-based adsorption of those available phosphate ions, the development [...] Read more.

Nutrient pollution of surface water, such as excess phosphate loading on lake surface water, is a significant issue that causes ecological and financial damage. Despite many technologies that can remove available phosphate, such as material-based adsorption of those available phosphate ions, the development of a material that can trap them from the surface water is worth doing, considering other aspects. These aspects are: (i) efficient adsorption by the material while it settles down to the water column, and (ii) the material itself is not toxic to the lake natural microorganism. Considering these aspects, we developed a trace lanthanum-grafted surface-modified palygorskite, a fibrous clay mineral. It adsorbed a realistic amount of phosphate from the lake water (typically 0.13–0.22 mg/L). The raw and modified palygorskite (Pal) includes unmodified Australian Pal, heated (at ~400 °C) Pal, and acid (with 3 M HCl)-treated Pal. Among them, while acid-treated Pal grafted a lower amount of La, it had a higher adsorption capacity (1.243 mg/g) and a quicker adsorption capacity in the time it took to travel to the bottom of the lake (97.6% in 2 h travel time), indicating the adsorption role of both La and clay mineral. The toxicity of these materials was recorded null, and in some period of the incubation of the lake microorganism with the material mixture, La-grafted modified clays increased microbial growth. As a total package, while a high amount of La on the already available material could adsorb a greater amount of phosphate, in this study a trace amount of La on modified clays showed adsorption effectiveness for the realistic amount of phosphate in lake water without posing added toxicity. Full article

(This article belongs to the Special Issue Novel Adsorbent for Environmental Remediation)

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13 pages, 1173 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Ammonium and Phosphate Recovery in a Three Chambered Microbial Electrolysis Cell: Towards Obtaining Struvite from Livestock Manure

by Míriam Cerrillo, Laura Burgos, Joan Noguerol, Victor Riau and August Bonmatí

Processes 2021, 9(11), 1916; https://doi.org/10.3390/pr9111916 - 27 Oct 2021

Cited by 9 | Viewed by 2802

Abstract

Ammonia and phosphate, which are present in large quantities in waste streams such as livestock manure, are key compounds in fertilization activities. Their recovery will help close natural cycles and take a step forward in the framework of a circular economy. In this [...] Read more.

Ammonia and phosphate, which are present in large quantities in waste streams such as livestock manure, are key compounds in fertilization activities. Their recovery will help close natural cycles and take a step forward in the framework of a circular economy. In this work, a lab-scale three-chambered microbial electrolysis cell (MEC) has been operated in continuous mode for the recovery of ammonia and phosphate from digested pig slurry in order to obtain a nutrient concentrated solution as a potential source of fertilizer (struvite). The maximum average removal efficiencies for ammonium and phosphate were 20% ± 4% and 36% ± 10%, respectively. The pH of the recovered solution was below 7, avoiding salt precipitation in the reactor. According to Visual MINTEQ software modelling, an increase of pH value to 8 outside the reactor would be enough to recover most of the potential struvite (0.21 mmol L⁻¹ d⁻¹), while the addition of up to 0.2 mM of magnesium to the nutrient recovered solution would enhance struvite production from 5.6 to 17.7 mM. The application of three-chambered MECs to the recovery of nutrients from high strength wastewater is a promising technology to avoid ammonia production through industrial processes or phosphate mineral extraction and close nutrient natural cycles. Full article

(This article belongs to the Special Issue Advanced Applications, Processes, and Materials in Microbial Electrochemical Technologies)

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20 pages, 5847 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Purification of Textile Effluents Containing C.I. Acid Violet 1: Adsorptive Removal versus Hydrogen Peroxide and Peracetic Acid Based Advanced Oxidation

by Monika Wawrzkiewicz, Urszula Kotowska and Aneta Sokół

Processes 2021, 9(11), 1911; https://doi.org/10.3390/pr9111911 - 26 Oct 2021

Cited by 10 | Viewed by 2401

Abstract

Textile effluent containing azo dyes such as C.I. Acid Violet 1 (AV1) can be degraded to toxic aromatic amines in the environment. Thus, there is a legitimate need to treat such effluents before they are discharged to surface waters. Two methods were proposed [...] Read more.

Textile effluent containing azo dyes such as C.I. Acid Violet 1 (AV1) can be degraded to toxic aromatic amines in the environment. Thus, there is a legitimate need to treat such effluents before they are discharged to surface waters. Two methods were proposed to remove AV1 from aqueous solutions: adsorption and advanced oxidation processes (AOPs). The sorption capacity of the strongly basic anion exchanger Purolite A520E of the polystyrene matrix determined from the Langmuir isotherm model was found to be 835 mg/g, while that of Lewatit S5428 of the polyacrylamide matrix Freundlich model seems to be more appropriate for describing the experimental data. The pseudo-second-order kinetic model and external diffusion are the rate limiting steps of adsorption. The removal efficiency of AV1 by the anion exchangers was higher than 99% after 40 min of phase contact time. AOPs involved the usage of hydrogen peroxide and peracetic acid (PAA) as oxidizing agents, while Fe²⁺ and simulated sunlight were used as oxidizing activators. AV1 oxidation followed the pseudo-first-order kinetics, and the systems with the highest values of the rate constants turned out to be those in which Fe²⁺ was present. The efficiency of oxidation measured by the degree of decolorization in the systems with Fe²⁺ was higher than 99% after 10–60 min. AV1 mineralization was slower, but after 120 min of oxidation it was higher than 98% in the H₂O₂/Fe²⁺, PAA/Fe²⁺ and PAA/Fe²⁺/sunlight systems. Full article

(This article belongs to the Special Issue Various Adsorbents for Water Purification Processes, Volume II)

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20 pages, 4674 KiB

Open AccessEditor’s ChoiceArticle

Novel Insights on the Sustainable Wet Mode Fractionation of Black Soldier Fly Larvae (Hermetia illucens) into Lipids, Proteins and Chitin

by Harish Karthikeyan Ravi, Côme Guidou, Jérôme Costil, Christophe Trespeuch, Farid Chemat and Maryline Abert Vian

Processes 2021, 9(11), 1888; https://doi.org/10.3390/pr9111888 - 22 Oct 2021

Cited by 8 | Viewed by 5700

Abstract

The black soldier fly larvae (BSFL) is a sustainable ingredient for feed applications, biofuels, composite materials and other biobased products. Processing BSFL to obtain lipid and protein fractions with enhanced functional properties as a suitable replacement for conventional feed ingredients has gained considerable [...] Read more.

The black soldier fly larvae (BSFL) is a sustainable ingredient for feed applications, biofuels, composite materials and other biobased products. Processing BSFL to obtain lipid and protein fractions with enhanced functional properties as a suitable replacement for conventional feed ingredients has gained considerable momentum. In this regard, a novel and sustainable wet mode fractionation (WMF) scheme for BSFL was explored. Fresh BSFL were steam blanched and pulped to obtain BSFL juice and juice press cake. Subsequent treatment of BSFL juice employing homogenization or enzyme incubation and further centrifugation resulted in the obtention of four different BSFL fractions (Lipid—LF; Cream—CF; Aqueous—AF; and Solid—SF). Total energy consumption for a batch BSFL (500 g) WMF process was 0.321 kWh. Aqueous and solid fractions were the predominant constituents of BSFL juice. Lauric acid (44.52–49.49%) and linoleic acid (19.12–20.12%) were the primary fatty acids present in BSFL lipids. Lipid hydrolysis was observed in lipids belonging to the solid (free fatty acids > triacylglycerides) and cream fractions. Aqueous fraction proteins (ctrl) displayed superior emulsion stability and foam capacity than other treatments. Juice press cake retained 60% of the total chitin content and the rest, 40%, was found in the solid fraction (ctrl). The material distribution of principal constituents in different fractions of the WMF process and amino acid profile was elucidated. Overall, the versatile WMF process proposed in this study involves simple unit operations to obtain functional ingredients from BSFL, which can be further explored by researchers and industry stakeholders. Full article

(This article belongs to the Special Issue Redesign Processes in the Age of the Fourth Industrial Revolution)

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26 pages, 3060 KiB

Open AccessFeature PaperEditor’s ChoiceReview

The Dark Side of Platinum Based Cytostatic Drugs: From Detection to Removal

by Yessica Roque-Diaz, Martina Sanadar, Dong Han, Montserrat López-Mesas, Manuel Valiente, Marilena Tolazzi, Andrea Melchior and Daniele Veclani

Processes 2021, 9(11), 1873; https://doi.org/10.3390/pr9111873 - 21 Oct 2021

Cited by 14 | Viewed by 4053

Abstract

The uncontrolled release of pharmaceutical drugs into the environment raised serious concerns in the last decades as they can potentially exert adverse effects on living organisms even at the low concentrations at which they are typically found. Among them, platinum based cytostatic drugs [...] Read more.

The uncontrolled release of pharmaceutical drugs into the environment raised serious concerns in the last decades as they can potentially exert adverse effects on living organisms even at the low concentrations at which they are typically found. Among them, platinum based cytostatic drugs (Pt CDs) are among the most used drugs in cancer treatments which are administered via intravenous infusion and released partially intact or as transformation products. In this review, the studies on environmental occurrence, transformation, potential ecotoxicity, and possible treatment for the removal of platinum cytostatic compounds are revised. The analysis of the literature highlighted the generally low total platinum concentration values (from a few tens of ng L⁻¹ to a few hundred μg L⁻¹) found in hospital effluents. Additionally, several studies highlighted how hospitals are sources of a minor fraction of the total Pt CDs found in the environment due to the slow excretion rate which is longer than the usual treatment durations. Only some data about the impact of the exposure to low levels of Pt CDs on the health of flora and fauna are present in literature. In some cases, adverse effects have been shown to occur in living organisms, even at low concentrations. Further ecotoxicity data are needed to support or exclude their chronic effects on the ecosystem. Finally, fundamental understanding is required on the platinum drugs removal by MBR, AOPs, technologies, and adsorption. Full article

(This article belongs to the Special Issue Advances in Nanomaterials for Selective Adsorption)

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20 pages, 26236 KiB

Open AccessEditor’s ChoiceArticle

Fast and Flexible mRNA Vaccine Manufacturing as a Solution to Pandemic Situations by Adopting Chemical Engineering Good Practice—Continuous Autonomous Operation in Stainless Steel Equipment Concepts

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

Processes 2021, 9(11), 1874; https://doi.org/10.3390/pr9111874 - 21 Oct 2021

Cited by 19 | Viewed by 6839

Abstract

SARS-COVID-19 vaccine supply for the total worldwide population has a bottleneck in manufacturing capacity. Assessment of existing messenger ribonucleic acid (mRNA) vaccine processing shows a need for digital twins enabled by process analytical technology approaches in order to improve process transfer for manufacturing [...] Read more.

SARS-COVID-19 vaccine supply for the total worldwide population has a bottleneck in manufacturing capacity. Assessment of existing messenger ribonucleic acid (mRNA) vaccine processing shows a need for digital twins enabled by process analytical technology approaches in order to improve process transfer for manufacturing capacity multiplication, a reduction in out-of-specification batch failures, qualified personal training for faster validation and efficient operation, optimal utilization of scarce buffers and chemicals and speed-up of product release by continuous manufacturing. In this work, three manufacturing concepts for mRNA-based vaccines are evaluated: Batch, full-continuous and semi-continuous. Technical transfer from batch single-use to semi-continuous stainless-steel, i.e., plasmid deoxyribonucleic acid (pDNA) in batch and mRNA in continuous operation mode, is recommended, in order to gain: faster plant commissioning and start-up times of about 8–12 months and a rise in dose number by a factor of about 30 per year, with almost identical efforts in capital expenditures (CAPEX) and personnel resources, which are the dominant bottlenecks at the moment, at about 25% lower operating expenses (OPEX). Consumables are also reduceable by a factor of 6 as outcome of this study. Further optimization potential is seen at consequent digital twin and PAT (Process Analytical Technology) concept integration as key-enabling technologies towards autonomous operation including real-time release-testing. Full article

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

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10 pages, 3314 KiB

Open AccessEditor’s ChoiceArticle

Effective Method for Evaluating Airflow Rate of Oscillating-Water-Column Pilot Plants

by Sewan Park, Kilwon Kim, Jeong-Hwan Oh, Chang-Hyuk Lim, Ji-Yong Park, Keyyong Hong and Seung-Ho Shin

Processes 2021, 9(11), 1884; https://doi.org/10.3390/pr9111884 - 21 Oct 2021

Cited by 1 | Viewed by 2137

Abstract

In this study, a method for effectively estimating the airflow rate of the turbine of an oscillating water column (OWC) pilot plant was developed. The validity of the proposed method was verified through computational fluid dynamics simulations. The method was applied to estimate [...] Read more.

In this study, a method for effectively estimating the airflow rate of the turbine of an oscillating water column (OWC) pilot plant was developed. The validity of the proposed method was verified through computational fluid dynamics simulations. The method was applied to estimate the airflow rate in irregular wave states based on the operation data obtained for the Yongsoo OWC pilot plant installed in the western seas of Jeju Island, South Korea. As an alternative to estimating the airflow rate of the OWC pilot plant, the impulse turbine performance chart-based interpolation method is introduced, and it is shown that the airflow rate time series calculated using the two methods were in good agreement. Full article

(This article belongs to the Section Energy Systems)

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19 pages, 8383 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Study on a Slotless Brushless DC Motor with Toroidal Winding

by Ho-Young Lee, Seung-Young Yoon, Soon-O Kwon, Jin-Yeong Shin, Soo-Hwan Park and Myung-Seop Lim

Processes 2021, 9(11), 1881; https://doi.org/10.3390/pr9111881 - 21 Oct 2021

Cited by 9 | Viewed by 8709

Abstract

In this study we developed a brushless DC (BLDC) slotless motor with toroidal winding. The proposed toroidal winding is a method of winding a coil around a ring-type stator yoke in the circumferential direction. As there is no need for a slot or [...] Read more.

In this study we developed a brushless DC (BLDC) slotless motor with toroidal winding. The proposed toroidal winding is a method of winding a coil around a ring-type stator yoke in the circumferential direction. As there is no need for a slot or tooth structure, it can be designed with a slotless motor structure that is advantageous for vibration and noise. The basic principle of operation and motor characteristics of a slotless motor with toroidal winding were explained using an analytical method and finite element analysis (FEA). Further, the air gap flux density, winding factor, and back electromotive force (EMF) for changes in the winding angle and number of coil turns were calculated using the analytical method and compared with the FEA results. Finally, the resistance, back EMF, cogging torque, and performance of the prototype were measured and compared with the FEA results. The results show that the air gap flux density and winding factor were approximately the same with an error of <2%, while the back EMF had an error of ~10% from the analysis result. Thus, the proposed slotless motor provides a basic design for conveniently manufacturing brushless DC (BLDC) slotless motors with toroidal windings. Full article

(This article belongs to the Special Issue Design, Concepts and Applications of Electric Machines)

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17 pages, 442 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Synthesizing Electrically Equivalent Circuits for Use in Electrochemical Impedance Spectroscopy through Grammatical Evolution

by Matevž Kunaver, Mark Žic, Iztok Fajfar, Tadej Tuma, Árpád Bűrmen, Vanja Subotić and Žiga Rojec

Processes 2021, 9(11), 1859; https://doi.org/10.3390/pr9111859 - 20 Oct 2021

Cited by 7 | Viewed by 2449

Abstract

Electrochemical impedance spectroscopy (EIS) is an important electrochemical technique that is used to detect changes and ongoing processes in a given material. The main challenge of EIS is interpreting the collected measurements, which can be performed in several ways. This article focuses on [...] Read more.

Electrochemical impedance spectroscopy (EIS) is an important electrochemical technique that is used to detect changes and ongoing processes in a given material. The main challenge of EIS is interpreting the collected measurements, which can be performed in several ways. This article focuses on the electrical equivalent circuit (EEC) approach and uses grammatical evolution to automatically construct an EEC that produces an AC response that corresponds to one obtained by the measured electrochemical process(es). For fitting purposes, synthetic measurements and data from measurements in a realistic environment were used. In order to be able to faithfully fit realistic data from measurements, a new circuit element (ZARC) had to be implemented and integrated into the SPICE simulator, which was used for evaluating EECs. Not only is the presented approach able to automatically (i.e., with almost no user input) produce a more than satisfactory EEC for each of the datasets, but it also can also generate completely new EEC configurations. These new configurations may help researchers to find some new, previously overlooked ongoing electrochemical processes. Full article

(This article belongs to the Special Issue Recent Advances of Solid Oxide Fuel Cells (SOFC))

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30 pages, 4298 KiB

Open AccessEditor’s ChoiceArticle

Pairing Experimental and Mathematical Modeling Studies on Fluidized Beds for Enhancement of Models Predictive Quality: A Current Status Overview

by Sebastián Uribe and Muthanna Al-Dahhan

Processes 2021, 9(11), 1863; https://doi.org/10.3390/pr9111863 - 20 Oct 2021

Cited by 1 | Viewed by 1831

Abstract

Modeling of gas-solid fluidized systems has been a prevailing challenge over the last few decades. With different approaches and implementing different sub-models to capture the essential multiphase and multiscale phenomena in these systems, major advances have been achieved, even though most models are [...] Read more.

Modeling of gas-solid fluidized systems has been a prevailing challenge over the last few decades. With different approaches and implementing different sub-models to capture the essential multiphase and multiscale phenomena in these systems, major advances have been achieved, even though most models are only subject to a practical validation of macroscopic parameters. The current description of fluidized beds through mathematical models relies on the inclusion of vast sub-models, leading to an unquantifiable degree of uncertainty on the models’ applicability for extrapolation studies. Furthermore, each closure and fitting parameter in the model represents a possible source of deviation, and their optimization, hence, becomes another major challenge. The recent advances in measurement techniques can enable us to troubleshoot and optimize the implemented models and sub-models based on local scale measurements. Local multiphase hydrodynamic information obtained by advanced measurement techniques can enable the validation of local predictions and optimization of the coupled sub-models, leading to the development of simplified and highly predictive models. Thus, pairing advanced experimental studies on these systems with insightful modeling approaches is required to advance the shortcoming and enhance the predictive quality of the models. In this work, an overview of the status of modeling and experimental measurement techniques for gas-solid fluidized beds is presented; then, an overview on pairing both experimental and modeling studies to improve the models’ local predictions for fluidized beds is presented. Full article

(This article belongs to the Special Issue Redesign Processes in the Age of the Fourth Industrial Revolution)

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23 pages, 4570 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Application of Computational Fluid Dynamics (CFD) Simulation for the Effective Design of Food 3D Printing (A Review)

by Timilehin Martins Oyinloye and Won Byong Yoon

Processes 2021, 9(11), 1867; https://doi.org/10.3390/pr9111867 - 20 Oct 2021

Cited by 21 | Viewed by 5815

Abstract

The progress of food 3D printing (3DP) applications demands a full understanding of the printing behavior of food materials. Computational fluid dynamics (CFD) simulation can help determine the optimum processing conditions for food 3DP such as layer height, deposit thickness, volume flow rate, [...] Read more.

The progress of food 3D printing (3DP) applications demands a full understanding of the printing behavior of food materials. Computational fluid dynamics (CFD) simulation can help determine the optimum processing conditions for food 3DP such as layer height, deposit thickness, volume flow rate, and nozzle shape and diameter under varied material properties. This paper mainly discusses the application of CFD simulation for three core processes associated with 3DP: (1) flow fields in the nozzle during the extrusion process; (2) die swelling of materials at the die (the exit part of the nozzle); and (3) the residual stress of printed products. The major achievements of CFD simulation in food 3DP with varied food materials are discussed in detail. In addition, the problems and potential solutions that modelers encountered when utilizing CFD in food 3DP were explored. Full article

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17 pages, 21894 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Influence of the Lamination Process on the Wetting Behavior and the Wetting Rate of Lithium-Ion Batteries

by Nicolaj Kaden, Nicolas Schlüter, Ruben Leithoff, Sinan Savas, Simon Grundmeier and Klaus Dröder

Processes 2021, 9(10), 1851; https://doi.org/10.3390/pr9101851 - 19 Oct 2021

Cited by 19 | Viewed by 5213

Abstract

In lithium-ion battery manufacturing, wetting of active materials is a time-critical process. Consequently, the impact of possible process chain extensions such as lamination needs to be explored to potentially improve the efficiency of the electrode and separator stacking process in battery cell manufacturing. [...] Read more.

In lithium-ion battery manufacturing, wetting of active materials is a time-critical process. Consequently, the impact of possible process chain extensions such as lamination needs to be explored to potentially improve the efficiency of the electrode and separator stacking process in battery cell manufacturing. This paper addresses the research gap of the unexplored effects of lamination on the wetting rate of electrode-separator assemblies in pouch cells. Based on the triangulation of three measurement techniques (gravimetric, optical, electrochemical), a correlation between lamination and wettability of electrode-separator assemblies is experimentally demonstrated, thus providing an important research contribution. Full article

(This article belongs to the Special Issue Production Technologies for Lithium-Ion Battery Electrodes, Cells and Systems)

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16 pages, 10833 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Relevance of Particle Size Distribution to Kinetic Analysis: The Case of Thermal Dehydroxylation of Kaolinite

by Juan Arcenegui-Troya, Pedro E. Sánchez-Jiménez, Antonio Perejón and Luis A. Pérez-Maqueda

Processes 2021, 9(10), 1852; https://doi.org/10.3390/pr9101852 - 19 Oct 2021

Cited by 11 | Viewed by 2203

Abstract

Kinetic models used for the kinetic analysis of solid-state reactions assume ideal conditions that are very rarely fulfilled by real processes. One of the assumptions of these ideal models is that all sample particles have an identical size, while most real samples have [...] Read more.

Kinetic models used for the kinetic analysis of solid-state reactions assume ideal conditions that are very rarely fulfilled by real processes. One of the assumptions of these ideal models is that all sample particles have an identical size, while most real samples have an inherent particle size distribution (PSD). In this study, the influence of particle size distribution, including bimodal PSD, in kinetic analysis is investigated. Thus, it is observed that PSD can mislead the identification of the kinetic model followed by the reaction and even induce complex thermoanalytical curves that could be misinterpreted in terms of complex kinetics or intermediate species. For instance, in the case of a bimodal PSD, kinetics is affected up to the point that the process resembles a reaction driven by a multi-step mechanism. A procedure for considering the PSD in the kinetic analysis is presented and evaluated experimentally by studying the thermal dehydroxylation of kaolinite. This process, which does not fit any of the common ideal kinetic models proposed in the literature, was analyzed considering PSD influence. However, when PSD is taken into account, the process can be successfully described by a 3-D diffusion model (Jander’s equation). Therefore, it is concluded that the deviations from ideal models for this dehydroxylation process could be explained in terms of PSD. Full article

(This article belongs to the Special Issue Thermal Analysis and Multi-Scale Modeling for Chemical Processes)

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28 pages, 10329 KiB

Open AccessEditor’s ChoiceArticle

Thermoeconomic Evaluation and Optimization of Using Different Environmentally Friendly Refrigerant Pairs for a Dual-Evaporator Cascade Refrigeration System

by Kasra Mohammadi and Kody M. Powell

Processes 2021, 9(10), 1855; https://doi.org/10.3390/pr9101855 - 19 Oct 2021

Cited by 2 | Viewed by 2462

Abstract

Applications of dual-evaporator refrigeration systems have recently gained much attention both in academia and industry due to their multiple benefits. In this study, a comprehensive thermodynamic and economic analysis is conducted to evaluate the potential of using several environmentally friendly refrigerant couples and [...] Read more.

Applications of dual-evaporator refrigeration systems have recently gained much attention both in academia and industry due to their multiple benefits. In this study, a comprehensive thermodynamic and economic analysis is conducted to evaluate the potential of using several environmentally friendly refrigerant couples and identifies the most suitable one yielding the best economic results. To achieve this goal, a detailed parametric study is conducted, and an optimization process is performed using a particle swarm optimization (PSO) approach to minimize the unit production cost of cooling (UPCC) of the cascade refrigeration system. The results showed that among all selected 18 refrigerant pairs and for all ranges of examined operating parameters, the R170-R161 pair and R1150-R1234yf pair are identified as the best and worst pairs, respectively, from both thermodynamic and economic viewpoints. The results also confirm that R170-R161 pair has an improvement over R717-R744, used as a typical refrigerant pair of cascade refrigeration cycles. For a base case analysis, the COP of R170-R161 and R1150-R1234yf pairs is determined as 1.727 and 1.552, respectively, while their UPCC is found to be $0.395/ton-hr and $0.419/ton-hr, respectively, showing the influence of proper selection of refrigerant pairs on the cascade cycle’s performance. Overall, this study offers a useful thermodynamic and economic insight regarding the selection of proper refrigerant pairs for a dual-evaporator cascade vapor compression refrigeration system. Full article

(This article belongs to the Special Issue Redesign Processes in the Age of the Fourth Industrial Revolution)

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21 pages, 2584 KiB

Open AccessEditor’s ChoiceArticle

Modified Dimension Reduction-Based Polynomial Chaos Expansion for Nonstandard Uncertainty Propagation and Its Application in Reliability Analysis

by Jeongeun Son and Yuncheng Du

Processes 2021, 9(10), 1856; https://doi.org/10.3390/pr9101856 - 19 Oct 2021

Cited by 2 | Viewed by 2016

Abstract

This paper presents an algorithm for efficient uncertainty quantification (UQ) in the presence of many uncertainties that follow a nonstandard distribution (e.g., lognormal). Using the polynomial chaos expansion (PCE), the algorithm builds surrogate models of uncertainty as functions of a standard distribution (e.g., [...] Read more.

This paper presents an algorithm for efficient uncertainty quantification (UQ) in the presence of many uncertainties that follow a nonstandard distribution (e.g., lognormal). Using the polynomial chaos expansion (PCE), the algorithm builds surrogate models of uncertainty as functions of a standard distribution (e.g., Gaussian variables). The key to build these surrogate models is to calculate PCE coefficients of model outputs, which is computationally challenging, especially when dealing with models defined by complex functions (e.g., nonpolynomial terms) under many uncertainties. To address this issue, an algorithm that integrates the PCE with the generalized dimension reduction method (gDRM) is utilized to convert the high-dimensional integrals, required to calculate the PCE coefficients of model predictions, into several lower-dimensional ones that can be rapidly solved with quadrature rules. The accuracy of the algorithm is validated with four examples in structural reliability analysis and compared to other existing techniques, such as Monte Carlo simulations and the least angle regression-based PCE. Our results show our algorithm provides accurate UQ results and is computationally efficient when dealing with many uncertainties, thus laying the foundation to address UQ in complex control systems. Full article

(This article belongs to the Special Issue Innovative Techniques for Safety, Reliability, and Security in Control Systems)

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13 pages, 1656 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Acidic and Heat Processing of Egg Yolk Dispersions

by José Manuel Aguilar, Manuel Felix, Yolanda López-González, Felipe Cordobés and Antonio Guerrero

Processes 2021, 9(10), 1842; https://doi.org/10.3390/pr9101842 - 17 Oct 2021

Cited by 1 | Viewed by 4095

Abstract

Egg yolk is a multifunctional ingredient widely used in many food products, wherein proteins are the dominant component contributing to this functionality. However, the potential risk of foodborne illness associated with egg use forces us to ensure that foodstuffs based on egg yolk [...] Read more.

Egg yolk is a multifunctional ingredient widely used in many food products, wherein proteins are the dominant component contributing to this functionality. However, the potential risk of foodborne illness associated with egg use forces us to ensure that foodstuffs based on egg yolk are managed in a safe and sanitary manner. Lowering the pH under a certain value by adding acids could serve this purpose, but it can also greatly modify the rheological and functional properties of egg yolk. This research aims to assess the influence of citric acid on the rheological properties and microstructure of chicken egg yolk dispersions and their heat-set gels. The dispersions were prepared from fresh hen’s eggs yolks by adding water or citric acid to obtain a technical yolk (45 wt.% in solids) at the desired pH value. Viscoelastic measurements were carried out using a control stress rheometer, and microstructure was evaluated by cryo-scanning electronic microscopy (CryoSEM). An evolution of the viscoelastic properties of egg yolk dispersions from fluid to gel behavior was observed as the pH decreased until 2 but showing a predominantly fluid behavior at pH 3. The profile of viscoelastic properties along the thermal cycle applied is modified to a great extent, also showing a strong dependence on pH. Thus, the sol–gel transition can be modulated by the pH value. Full article

(This article belongs to the Special Issue Method Optimization of Various Food Processing Technologies)

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14 pages, 855 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Extraction Methods of Oils and Phytochemicals from Seeds and Their Environmental and Economic Impacts

by Valerie M. Lavenburg, Kurt A. Rosentrater and Stephanie Jung

Processes 2021, 9(10), 1839; https://doi.org/10.3390/pr9101839 - 16 Oct 2021

Cited by 49 | Viewed by 22963

Abstract

Over recent years, the food industry has striven to reduce waste, mostly because of rising awareness of the detrimental environmental impacts of food waste. While the edible oils market (mostly represented by soybean oil) is forecasted to reach 632 million tons by 2022, [...] Read more.

Over recent years, the food industry has striven to reduce waste, mostly because of rising awareness of the detrimental environmental impacts of food waste. While the edible oils market (mostly represented by soybean oil) is forecasted to reach 632 million tons by 2022, there is increasing interest to produce non-soybean, plant-based oils including, but not limited to, coconut, flaxseed and hemp seed. Expeller pressing and organic solvent extractions are common methods for oil extraction in the food industry. However, these two methods come with some concerns, such as lower yields for expeller pressing and environmental concerns for organic solvents. Meanwhile, supercritical CO₂ and enzyme-assisted extractions are recognized as green alternatives, but their practicality and economic feasibility are questioned. Finding the right balance between oil extraction and phytochemical yields and environmental and economic impacts is challenging. This review explores the advantages and disadvantages of various extraction methods from an economic, environmental and practical standpoint. The novelty of this work is how it emphasizes the valorization of seed by-products, as well as the discussion on life cycle, environmental and techno-economic analyses of oil extraction methods. Full article

(This article belongs to the Special Issue Extraction and Fractionation Processes of Functional Components in Food Engineering)

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15 pages, 4463 KiB

Open AccessEditor’s ChoiceArticle

Recovery of Water from Textile Dyeing Using Membrane Filtration Processes

by Joanna Marszałek and Renata Żyłła

Processes 2021, 9(10), 1833; https://doi.org/10.3390/pr9101833 - 15 Oct 2021

Cited by 30 | Viewed by 3984

Abstract

The aim of the work was to purify model textile wastewater (MTW) using a two-stage membrane filtration process comprising nanofiltration (NF) and reverse osmosis (RO). For this purpose, a nanofiltration membrane TFC-SR3 (KOCH) and reverse osmosis membrane AG (GE Osmonics) were used. Each [...] Read more.

The aim of the work was to purify model textile wastewater (MTW) using a two-stage membrane filtration process comprising nanofiltration (NF) and reverse osmosis (RO). For this purpose, a nanofiltration membrane TFC-SR3 (KOCH) and reverse osmosis membrane AG (GE Osmonics) were used. Each model wastewater contained a selected surfactant. The greatest decrease in flux in the initial phase of the process occurred for the detergents based on fatty-acid condensation products. An evident decrease in performance was observed with polysiloxane-based surfactants. No fouling effect and high flux values were observed for the wastewater containing a nonionic surfactant based on fatty alcohol ethoxylates. During RO, a significantly higher flux and lower resistance were observed for the feed that originally contained the anionic agent. For the MTW containing the nonionic surfactant, the conductivity reduction ranged from 84% to 92% depending on the concentrate ratio at the consecutive stages of RO. After treatment, the purified wastewater was reused in the process of dyeing cellulose fibers with reactive dyes. The research confirmed that textiles dyed with the use of RO filtrates did not differ in quality of dyeing from those dyed in pure deionized water. Full article

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17 pages, 17831 KiB

Open AccessEditor’s ChoiceArticle

Comprehensive Understanding of Roller Milling on the Physicochemical Properties of Red Lentil and Yellow Pea Flours

by Manoj Kumar Pulivarthi, Eric Nkurikiye, Jason Watt, Yonghui Li and Kaliramesh Siliveru

Processes 2021, 9(10), 1836; https://doi.org/10.3390/pr9101836 - 15 Oct 2021

Cited by 18 | Viewed by 3352

Abstract

The development of convenience foods by incorporating nutrient-rich pulses such as peas and lentils will tremendously alter the future of pulse and cereal industries. However, these pulses should be size-reduced before being incorporated into many food products. Therefore, an attempt was made to [...] Read more.

The development of convenience foods by incorporating nutrient-rich pulses such as peas and lentils will tremendously alter the future of pulse and cereal industries. However, these pulses should be size-reduced before being incorporated into many food products. Therefore, an attempt was made to adapt roller mill settings to produce de-husked yellow pea and red lentil flours. The milling flowsheets unique to yellow peas and red lentils were developed in producing small, medium, and large flours with maximum yield and flour quality. This study also investigated the differences in chemical composition, physical characteristics, and particle size distributions of the resultant six flour fractions. The kernel dimensions and physicochemical properties of the whole yellow pea and red lentils were also studied to develop customized mill settings. Overall, the mill settings had a significant effect on the physical properties of different particle-sized flours. The geometric mean diameters of different particle-sized red lentil flours were 56.05 μm (small), 67.01 μm (medium), and 97.17 μm (large), while for yellow pea flours they were 41.38 μm (small), 60.81 μm (medium), and 98.31 μm (large). The particle size distribution of all the flour types showed a bimodal distribution, except for the small-sized yellow pea flour. For both the pulse types, slightly more than 50% flour was approximately sizing 50 μm, 75 μm, and 100 μm for small, medium, and large settings, respectively. The chemical composition of the flour types remained practically the same for different-sized flours, fulfilling the objective of this current study. The damaged starch values for red lentil and yellow pea flour types increased with a decrease in flour particle size. Based on the Hausner’s ratios, the flowability of large-sized flour of red lentils could be described as passable; however, all the remaining five flour types were indicated as either poor or very poor. The findings of this study assist the millers to adapt yellow pea and red lentil milling technologies with minor modifications to the existing facilities. The study also helps in boosting the production of various baking products using pulse and wheat flour blends to enhance their nutritional quality. Full article

(This article belongs to the Special Issue Processing and Properties Analysis of Grain Foods)

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16 pages, 3260 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Layered Double Hydroxides as a Drug Delivery Vehicle for S-Allyl-Mercapto-Cysteine (SAMC)

by Ivan Vito Ferrari, Riccardo Narducci, Giuseppe Prestopino, Ferdinando Costantino, Alessio Mattoccia, Lina Di Giamberardino, Morena Nocchetti, Maria Luisa Di Vona, Annalisa Paolone, Marzia Bini, Riccardo Pezzilli, Ilaria Borromeo, Simone Beninati and Pier Gianni Medaglia

Processes 2021, 9(10), 1819; https://doi.org/10.3390/pr9101819 - 14 Oct 2021

Cited by 6 | Viewed by 2838

Abstract

The intercalations of anionic molecules and drugs in layered double hydroxides (LDHs) have been intensively investigated in recent years. Due to their properties, such as versatility in chemical composition, good biocompatibility, high density and protection of loaded drugs, LDHs seem very promising nanosized [...] Read more.

The intercalations of anionic molecules and drugs in layered double hydroxides (LDHs) have been intensively investigated in recent years. Due to their properties, such as versatility in chemical composition, good biocompatibility, high density and protection of loaded drugs, LDHs seem very promising nanosized systems for drug delivery. In this work, we report the intercalation of S-allyl-mercapto-cysteine (SAMC), which is a component of garlic that is well-known for its anti-tumor properties, inside ZnAl-LDH (hereafter LDH) nanostructured crystals. In order to investigate the efficacy of the intercalation and drug delivery of SAMC, the intercalated compounds were characterized using X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The increase in the interlayer distance of LDH from 8.9 Å, typical of the nitrate phase, to 13.9 Å indicated the intercalation of SAMC, which was also confirmed using FT-IR spectra. Indeed, compared to that of the pristine LDH precursor, the spectrum of LDH-SAMC was richly structured in the fingerprint region below 1300 cm⁻¹, whose peaks corresponded to those of the functional groups in the SAMC molecular anion. The LDH-SAMC empirical formula, obtained from UV-Vis spectrophotometry and thermogravimetric analysis, was [Zn_0.67Al_0.33(OH)₂]SAMC_0.15(NO₃)_0.18·0.6H₂O. The morphology of the sample was investigated using SEM: LDH-SAMC exhibited a more irregular size and shape of the flake-like crystals in comparison with the pristine LDH, with a reduction in the average crystallite size from 3 µm to about 2 µm. In vitro drug release studies were performed in a phosphate buffer solution at pH 7.2 and 37 °C and were analyzed using UV-Vis spectrophotometry. The SAMC release from LDH-SAMC was initially characterized by a burst effect in the first four hours, during which, 32% of the SAMC is released. Subsequently, the release percentage increased at a slower rate until 42% after 48 h; then it stabilized at 43% and remained constant for the remaining period of the investigation. The LDH-SAMC complex that was developed in this study showed the improved efficacy of the action of SAMC in reducing the invasive capacity of a human hepatoma cell line. Full article

(This article belongs to the Section Materials Processes)

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14 pages, 3591 KiB

Open AccessEditor’s ChoiceArticle

Electromagnetic Analysis and Experimental Study to Optimize Force Characteristics of Permanent Magnet Synchronous Generator for Wave Energy Converter Using Subdomain Method

by Kyung-Hun Shin, Tae-Kyoung Bang, Kyong-Hwan Kim, Keyyong Hong and Jang-Young Choi

Processes 2021, 9(10), 1825; https://doi.org/10.3390/pr9101825 - 14 Oct 2021

Cited by 4 | Viewed by 2008

Abstract

This paper presents an electromagnetic analysis and experimental verification to optimize the noise, vibration, and harshness (NVH) characteristics of a permanent magnet synchronous generator (PMSG) for wave energy converters (WECs). WECs applicable to breakwater installed in island areas require a wider operating range [...] Read more.

This paper presents an electromagnetic analysis and experimental verification to optimize the noise, vibration, and harshness (NVH) characteristics of a permanent magnet synchronous generator (PMSG) for wave energy converters (WECs). WECs applicable to breakwater installed in island areas require a wider operating range and a robust design for maintenance compared with wind-turbine systems. Owing to the use of a permanent magnet with a high energy density, the PMSG has a higher power density than other types of generators; however, strong electromagnetic excitation forces that affect the NVH characteristics are generated. Therefore, in this study, the electromagnetic forces are analyzed through an electromagnetic-field analysis using a subdomain analytical method. Based on the analytical solution, electromagnetic forces were determined. Four electromagnetic excitation forces were classified, and the methods for reducing electromagnetic excitation forces are presented here. Finally, a method for evaluating the system resonance through electromechanical analysis is presented. The proposed analysis, optimization, and experimental study are validated through comparison with finite-element analysis and experimental results. Full article

(This article belongs to the Section Energy Systems)

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17 pages, 2561 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Parameter Identification of a Quasi-3D PEM Fuel Cell Model by Numerical Optimization

by Maximilian Haslinger, Christoph Steindl and Thomas Lauer

Processes 2021, 9(10), 1808; https://doi.org/10.3390/pr9101808 - 12 Oct 2021

Cited by 3 | Viewed by 2534

Abstract

Polymer electrolyte membrane fuel cells (PEMFCs) supplied with green hydrogen from renewable sources are a promising technology for carbon dioxide-free energy conversion. Many mathematical models to describe and understand the internal processes have been developed to design more powerful and efficient PEMFCs. Parameterizing [...] Read more.

Polymer electrolyte membrane fuel cells (PEMFCs) supplied with green hydrogen from renewable sources are a promising technology for carbon dioxide-free energy conversion. Many mathematical models to describe and understand the internal processes have been developed to design more powerful and efficient PEMFCs. Parameterizing such models is challenging, but indispensable to predict the species transport and electrochemical conversion accurately. Many material parameters are unknown, or the measurement methods required to determine their values are expensive, time-consuming, and destructive. This work shows the parameterization of a quasi-3D PEMFC model using measurements from a stack test stand and numerical optimization algorithms. Differential evolution and the Nelder–Mead simplex algorithm were used to optimize eight material parameters of the membrane, cathode catalyst layer (CCL), and gas diffusion layer (GDL). Measurements with different operating temperatures and gas inlet pressures were available for optimization and validation. Due to the low operating temperature of the stack, special attention was paid to the temperature dependent terms in the governing equations. Simulations with optimized parameters predicted the steady-state and transient behavior of the stack well. Therefore, valuable data for the characterization of the membrane, the CCL and GDL was created that can be used for more detailed CFD simulations in the future. Full article

(This article belongs to the Special Issue Experimental Analysis and Numerical Simulation of Fuel Cells)

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20 pages, 4213 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Composition of Oil after Hydrothermal Treatment of Cabonate-Siliceous and Carbonate Domanic Shale Rocks

by Galina P. Kayukova, Zukhra R. Nasyrova, Anastasiya N. Mikhailova, Igor P. Kosachev, Firdavs A. Aliev and Alexey V. Vakhin

Processes 2021, 9(10), 1798; https://doi.org/10.3390/pr9101798 - 11 Oct 2021

Cited by 4 | Viewed by 1959

Abstract

The hydrocarbon compositions of shale oils, generated from two different lithological–facial Domanic deposits of the Tatarstan Republic (Russia), were studied under hydrothermal impact with 30% of water addition in a 350 °С and CO₂ environment. The samples were extracted from carbonate–siliceous rocks [...] Read more.

The hydrocarbon compositions of shale oils, generated from two different lithological–facial Domanic deposits of the Tatarstan Republic (Russia), were studied under hydrothermal impact with 30% of water addition in a 350 °С and CO₂ environment. The samples were extracted from carbonate–siliceous rocks of the Semiluky–Mendym deposits of the Berezovskaya area, and carbonate deposits of the Dankovo–Lebedyan horizon of the Zelenogorskaya area of the Romashkino oil field. The distinctive features of rocks are in the composition and content of organic matter (OM), its thermal stability, as well as the structural-group composition of the shale oil products. The hydrothermal treatment of the rock samples increased the content of saturates and decreased the content of aromatics, resins and asphaltenes in the composition of crude oil. The decomposition of the polymer-like kerogen structure and destruction processes of high-molecular compounds, such as resins and asphaltenes, are accompanied with the formation of substances highly rich in carbons—carbenes and carboids. The contents of n-alkanes and acyclic isoprenoids increase in the composition of saturated hydrocarbons. According to the chemical classification of Al. A. Petrov, the character of the molecular mass distribution of such substances corresponds to oil type A¹, which is considered paraffinic. The contents of dibenzothiophene, naphthalene and phenanthrene are increased in the composition of aromatic hydrocarbons, while the contents of tri-methyl-alkyl-benzene and benzothiophene are decreased. The increase in the aryl isoprenoid ratio (AIR = С₁₃–С₁₇/С₁₈–С₂₂) and maturity parameter (4-MDBT/1-MDBT) under the influences of hydrothermal factors indicates the increasing thermal maturity degree of the hydrocarbon system. The differences in the distribution behavior of saturated and aromatic hydrocarbons—biomarkers in rocks of various lithological-facies types, which are reasoned by different conditions of initial organic matter transformation as well as under the impact of hydrothermal factors—were revealed. Full article

(This article belongs to the Special Issue Heavy Oils Conversion Processes (II))

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21 pages, 960 KiB

Open AccessEditor’s ChoiceArticle

Robust Detection of Minute Faults in Uncertain Systems Using Energy Activity

by Manarshhjot Singh, Anne-Lise Gehin and Belkacem Ould-Boaumama

Processes 2021, 9(10), 1801; https://doi.org/10.3390/pr9101801 - 11 Oct 2021

Cited by 3 | Viewed by 1861

Abstract

Fault detection is one of the key steps in Fault Detection and Isolation (FDI) and, therefore, critical for subsequent prognosis or implementation of Fault Tolerant Control (FTC). It is, therefore, advisable to utilize detection algorithms which are quick and can detect the smallest [...] Read more.

Fault detection is one of the key steps in Fault Detection and Isolation (FDI) and, therefore, critical for subsequent prognosis or implementation of Fault Tolerant Control (FTC). It is, therefore, advisable to utilize detection algorithms which are quick and can detect the smallest faults. Model-based detection methods satisfy both these criteria and should be preferred. However, a big limitation for model-based methods is that they require the accurate value of the component parameters, which is difficult to obtain in real situations. This limits the accuracy of model-based methods. This paper proposes a new method for fault detection using Energy Activity (EA) which can detect minute levels of fault in systems with high component uncertainty. Different forms of EA are developed for use as an FDI metric. The proposed forms are simulated using a two-tank system under various types of faults. The results are compared with each other and with the traditional model-based FDI method using Analytical Redundancy Relations (ARRs). The simulations are performed considering model uncertainties to check the inherent performance of the methods. From initial simulations, it is established that the integral form of EA is most suited for fault detection. The integral for if EA is then tested using a real two-tank system considering both the model and measurement uncertainties. Full article

(This article belongs to the Special Issue Process Monitoring and Fault Diagnosis)

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11 pages, 1023 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Environmental and Sustainability Analysis of a Supercritical Carbon Dioxide-Assisted Process for Pharmaceutical Applications

by Paolo Trucillo, Roberta Campardelli and Iolanda De Marco

Processes 2021, 9(10), 1788; https://doi.org/10.3390/pr9101788 - 8 Oct 2021

Cited by 1 | Viewed by 1816

Abstract

Drug delivery systems (DDS) are artificial devices employed to enhance drug bioavailability during administration to a human body. Among DDS, liposomes are spherical vesicles made of an aqueous core surrounded by phospholipids. Conventional production methods are characterized by several drawbacks; therefore, Supercritical assisted [...] Read more.

Drug delivery systems (DDS) are artificial devices employed to enhance drug bioavailability during administration to a human body. Among DDS, liposomes are spherical vesicles made of an aqueous core surrounded by phospholipids. Conventional production methods are characterized by several drawbacks; therefore, Supercritical assisted Liposome formation (SuperLip) has been developed to overcome these problems. Considering that the use of high pressures involves high energy cost, in this paper, sustainability indicators were calculated to quantitatively evaluate the emissions related to the attainment of liposomes containing daunorubicin (a model antibiotic drug) using the SuperLip process. The indicators were depicted using a spider diagram to raise the actual weaknesses of this technique; some variations were proposed in the process layout to solve the critical issues. According to the literature, many studies related to the pharmaceutical industry are expressed in terms of solid, liquid waste, and toxic emissions; however, liposomes have never explicitly been considered for an analysis of environmental sustainability. Full article

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

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10 pages, 1024 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Investigating the Solubility and Activity of a Novel Class of Ice Recrystallization Inhibitors

by Anna A. Ampaw, Kayla Newell and Robert N. Ben

Processes 2021, 9(10), 1781; https://doi.org/10.3390/pr9101781 - 6 Oct 2021

Cited by 2 | Viewed by 2845

Abstract

O-aryl-β-d-glucosides and N-alkyl-d-gluconamides are two classes of effective ice recrystallization inhibitors (IRIs), however their solubilities limit their use in cryopreservation applications. Herein, we have synthesized and assessed phosphonate analogues of small-molecule IRIs as a method to improve [...] Read more.

O-aryl-β-d-glucosides and N-alkyl-d-gluconamides are two classes of effective ice recrystallization inhibitors (IRIs), however their solubilities limit their use in cryopreservation applications. Herein, we have synthesized and assessed phosphonate analogues of small-molecule IRIs as a method to improve their chemical and physical properties. Four sodium phosphonate compounds 4–7 were synthesized and exhibited high solubilities greater than 200 mM. Their IRI activity was evaluated using the splat cooling assay and only the sodium phosphonate derivatives of α-methyl-d-glucoside (5-Na) and N-octyl-d-gluconamide (7-Na) exhibited an IC₅₀ value less than 30 mM. It was found that the addition of a polar sodium phosphonate group to the alkyl gluconamide (1) and aryl glucoside (2) structure decreased its IRI activity, indicating the importance of a delicate hydrophobic/hydrophilic balance within these compounds. The evaluation of various cation-phosphonate pairs was studied and revealed the IRI activity of ammonium and its ability to modulate the IRI activity of its paired anion. A preliminary cytotoxicity study was also performed in a HepG2 cell line and phosphonate analogues were found to have relatively low cytotoxicity. As such, we present phosphonate small-molecule carbohydrates as a biocompatible novel class of IRIs with high solubilities and moderate-to-high IRI activities. Full article

(This article belongs to the Special Issue Study on Bio-Thermofluid Dynamics)

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14 pages, 1808 KiB

Open AccessEditor’s ChoiceArticle

Microwave Radiation Influence on Dairy Waste Anaerobic Digestion in a Multi-Section Hybrid Anaerobic Reactor (M-SHAR)

by Marcin Zieliński, Marcin Dębowski and Joanna Kazimierowicz

Processes 2021, 9(10), 1772; https://doi.org/10.3390/pr9101772 - 2 Oct 2021

Cited by 16 | Viewed by 2495

Abstract

Whey is a primary by-product of dairy plants, and one that is often difficult to manage. As whey processing units are costly and complicated, only 15–20% of whey is recycled for use in the food industry. The difficulties in managing waste whey are [...] Read more.

Whey is a primary by-product of dairy plants, and one that is often difficult to manage. As whey processing units are costly and complicated, only 15–20% of whey is recycled for use in the food industry. The difficulties in managing waste whey are particularly pronounced for small, local dairy plants. One possible solution to this problem is to use advanced and efficient digesters. The aim of this study was to present an innovative multi-section hybrid anaerobic bioreactor (M-SHAR) design and to identify how microwave radiation heating (MRH) affects methane fermentation of liquid dairy waste (LDW) primarily composed of acid whey. The MRH reactor was found to perform better in terms of COD removal and biogas production compared with the convection-heated reactor. The heating method had a significant differentiating effect at higher organic load rates (OLRs). With OLRs ranging from 15 to 25 kg_COD∙m⁻³∙d⁻¹, the M-SHAR with MRH ensured a 5% higher COD removal efficiency and 12–20% higher biogas yields. Full article

(This article belongs to the Special Issue Biomass Processing and Conversion Systems, Volume II)

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21 pages, 2578 KiB

Open AccessEditor’s ChoiceArticle

Extraction of Chlorobenzenes and PCBs from Water by ZnO Nanoparticles

by Yuntao Zhang, Ran Chen, Jim E. Riviere and Jeffrey Comer

Processes 2021, 9(10), 1764; https://doi.org/10.3390/pr9101764 - 1 Oct 2021

Viewed by 2687

Abstract

Metal oxide nanoparticles have great potential for selective adsorption and catalytic degradation of contaminants from aqueous solutions. In this study, we employ mass spectrometry and molecular dynamics simulations to better understand the chemical and physical mechanisms determining the affinity of chlorobenzenes and polychlorinated [...] Read more.

Metal oxide nanoparticles have great potential for selective adsorption and catalytic degradation of contaminants from aqueous solutions. In this study, we employ mass spectrometry and molecular dynamics simulations to better understand the chemical and physical mechanisms determining the affinity of chlorobenzenes and polychlorinated biphenyls (PCBs) for zinc oxide nanoparticles (ZnO NPs). The experiments and simulations both demonstrate that the adsorption coefficients for chlorobenzenes increase steadily with the number of chlorine atoms, while, for PCBs, the relation is more complex. The simulations link this complexity to chlorine atoms at ortho positions hindering coplanar conformations. For a given number of chlorine atoms, the simulations predict decreasing adsorption affinity with increasing numbers of ortho substitutions. Consequently, the simulations predict that some of the highest adsorption affinities for ZnO NPs are exhibited by dioxin-like PCBs, suggesting the possibility of selective sequestration of these most acutely toxic PCBs. Remarkably, the experiments show that the PCB adsorption coefficients of ZnO NPs with diameters ≤ 80 nm exceed those of a soil sample by 5–7 orders of magnitude, meaning that a single gram of ZnO NPs could sequester low levels of PCB contamination from as much as a ton of soil. Full article

(This article belongs to the Special Issue Novel Adsorbent for Environmental Remediation)

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10 pages, 228 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Evaluation of Hammermill Tip Speed, Air Assist, and Screen Hole Diameter on Ground Corn Characteristics

by Michaela Braun, Haley Wecker, Kara Dunmire, Caitlin Evans, Michael W. Sodak, Maks Kapetanovich, Jerry Shepherd, Randy Fisher, Kyle Coble, Charles Stark and Chad Paulk

Processes 2021, 9(10), 1768; https://doi.org/10.3390/pr9101768 - 1 Oct 2021

Cited by 3 | Viewed by 2570

Abstract

This study was performed to evaluate hammermill tip speed, assistive airflow, and screen hole diameter on hammermill throughput and characteristics of ground corn. Corn was ground using two Andritz hammermills measuring 1 m in diameter each equipped with 72 hammers and 300 HP [...] Read more.

This study was performed to evaluate hammermill tip speed, assistive airflow, and screen hole diameter on hammermill throughput and characteristics of ground corn. Corn was ground using two Andritz hammermills measuring 1 m in diameter each equipped with 72 hammers and 300 HP motors. Treatments were arranged in a 3 × 3 × 3 factorial design with three tip speeds (3774, 4975, and 6176 m/min), three screen hole diameters (2.3, 3.9, and 6.3 mm), and three air flow rates (1062, 1416, and 1770 fan revolutions per minute). Corn was ground on three separate days to create three replications and treatments were randomized within day. Samples were collected and analyzed for moisture, particle size, and flowability characteristics. There was a 3-way interaction (p = 0.029) for standard deviation (S_gw). There was a screen hole diameter × hammer tip speed interaction (p < 0.001) for geometric mean particle size d_gw (p < 0.001) and composite flow index (CFI) (p < 0.001). When tip speed increased from 3774 to 6176 m/min, the rate of decrease in dgw was greater as screen hole diameter increased from 2.3 to 6.3 mm. For CFI, increasing tip speed decreased the CFI of ground corn when ground using the 3.9 and 6.3 mm screen. However, when grinding corn using the 2.3 mm screen, there was no evidence of difference in CFI when increasing tip speed. In conclusion, the air flow rate did not influence d_gw of corn, but hammer tip speed and screen size were altered and achieved a range of d_gw from 304 to 617 µm. Full article

(This article belongs to the Special Issue Processing and Properties Analysis of Grain Foods)

17 pages, 2484 KiB

Open AccessEditor’s ChoiceArticle

Electrochemical Performance of Aluminum Doped Ni_1−xAl_xCo₂O₄ Hierarchical Nanostructure: Experimental and Theoretical Study

by Deepa Guragain, Romakanta Bhattarai, Jonghyun Choi, Wang Lin, Ram Krishna Gupta, Xiao Shen, Felio A. Perez and Sanjay R. Mishra

Processes 2021, 9(10), 1750; https://doi.org/10.3390/pr9101750 - 30 Sep 2021

Cited by 8 | Viewed by 2644

Abstract

For electrochemical supercapacitors, nickel cobaltite (NiCo₂O₄) has emerged as a new energy storage material. The electrocapacitive performance of metal oxides is significantly influenced by their morphology and electrical characteristics. The synthesis route can modulate the morphological structure, while their [...] Read more.

For electrochemical supercapacitors, nickel cobaltite (NiCo₂O₄) has emerged as a new energy storage material. The electrocapacitive performance of metal oxides is significantly influenced by their morphology and electrical characteristics. The synthesis route can modulate the morphological structure, while their energy band gaps and defects can vary the electrical properties. In addition to modifying the energy band gap, doping can improve crystal stability and refine grain size, providing much-needed surface area for high specific capacitance. This study evaluates the electrochemical performance of aluminum-doped Ni_1−xAl_xCo₂O₄ (0 ≤ x ≤ 0.8) compounds. The Ni_1−xAl_xCo₂O₄ samples were synthesized through a hydrothermal method by varying the Al to Ni molar ratio. The physical, morphological, and electrochemical properties of Ni_1−xAl_xCo₂O₄ are observed to vary with Al³⁺ content. A morphological change from urchin-like spheres to nanoplate-like structures with a concomitant increase in the surface area, reaching up to 189 m²/g for x = 0.8, was observed with increasing Al³⁺ content in Ni_1−xAl_xCo₂O₄. The electrochemical performance of Ni_1−xAl_xCo₂O₄ as an electrode was assessed in a 3M KOH solution. The high specific capacitance of 512 F/g at a 2 mV/s scan rate, 268 F/g at a current density of 0.5 A/g, and energy density of 12.4 Wh/kg was observed for the x = 0.0 sample, which was reduced upon further Al³⁺ substitution. The as-synthesized Ni_1−xAl_xCo₂O₄ electrode exhibited a maximum energy density of 12.4 W h kg⁻¹ with an outstanding high-power density of approximately 6316.6 W h kg⁻¹ for x = 0.0 and an energy density of 8.7 W h kg⁻¹ with an outstanding high-power density of approximately 6670.9 W h kg⁻¹ for x = 0.6. The capacitance retention of 97% and 108.52% and the Coulombic efficiency of 100% and 99.24% were observed for x = 0.0 and x = 0.8, respectively. First-principles density functional theory (DFT) calculations show that the band-gap energy of Ni_1−xAl_xCo₂O₄ remained largely invariant with the Al³⁺ substitution for low Al³⁺ content. Although the capacitance performance is reduced upon Al³⁺ doping, overall, the Al³⁺ doped Ni_1−xAl_xCo₂O₄ displayed good energy, powder density, and retention performance. Thus, Al³⁺ could be a cost-effective alternative in replacing Ni with the performance trade off. Full article

(This article belongs to the Special Issue Redesign Processes in the Age of the Fourth Industrial Revolution)

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15 pages, 604 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Feature Selection and Uncertainty Analysis for Bubbling Fluidized Bed Oxy-Fuel Combustion Data

by Katerina Marzova and Ivo Bukovsky

Processes 2021, 9(10), 1757; https://doi.org/10.3390/pr9101757 - 30 Sep 2021

Cited by 1 | Viewed by 1460

Abstract

This paper presents a novel feature extraction and validation technique for data-driven prediction of oxy-fuel combustion emissions in a bubbling fluidized bed experimental facility. The experimental data were analyzed and preprocessed to minimize the size of the data set while preserving patterns and [...] Read more.

This paper presents a novel feature extraction and validation technique for data-driven prediction of oxy-fuel combustion emissions in a bubbling fluidized bed experimental facility. The experimental data were analyzed and preprocessed to minimize the size of the data set while preserving patterns and variance and to find an optimal configuration of the feature vector. The Boruta Feature Selection Algorithm (BFSA) finds feature vector’s configuration and the Multiscale False Neighbours Analysis (MSFNA) is newly extended and proposed to validate the BFSA’s design for emission prediction to assure minimal uncertainty in mapping between feature vectors and corresponding outputs. The finding is that the standalone BFSA does not reflect various sampling period setups that appeared significantly influencing the false neighborhood in the design of feature vectors for possible emission prediction, and MSFNA resolves that. Full article

(This article belongs to the Special Issue Modelling, Simulation and Control in Combustion Processes of Renewable Fuels)

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8 pages, 843 KiB

Open AccessEditor’s ChoiceArticle

An Effective New Treatment of Fluoride-Containing Sludge Resulting from the Manufacture of Photovoltaic Cells

by Svetlana Zueva, Francesco Ferella, Valentina Corradini, Elena V. Baturina, Nicolò M. Ippolito and Francesco Vegliò

Processes 2021, 9(10), 1745; https://doi.org/10.3390/pr9101745 - 29 Sep 2021

Cited by 3 | Viewed by 2923

Abstract

The circular economy and maximization of environmental sustainability are increasingly becoming the vision and mission of companies competing in present-day global markets. In particular, in the energy sector, the transition from fossil fuels to renewable sources of energy has become the widespread mantra. [...] Read more.

The circular economy and maximization of environmental sustainability are increasingly becoming the vision and mission of companies competing in present-day global markets. In particular, in the energy sector, the transition from fossil fuels to renewable sources of energy has become the widespread mantra. One typical example is the deployment of devices which produce clean energy, such as solar photovoltaic panels and solar thermal panels, wind generators, tidal stream generators, wave power generators, etc. These are undoubtedly generating clean energy, but their manufacture creates hazardous by-products, the disposal of which results in increased environmental pollution. Chemical Vapor Deposition (CVD) is widely used in manufacturing of solar photovoltaic cells. In these processes, typically, crystalline silicon is precipitated from chlorosilanes, iodides, bromides and fluorides. Polluting by-products include deposition of a silicon film, formation of SiO₂ powder and formation of toxic vapors of HF, SiH₄ and PH₃. Usually, these gaseous products are eliminated in a central scrubber, whose unwanted by-product consists in large quantities of hazardous fluorine-containing sludge. This article concerns an effective and inexpensive detoxification of fluorinated sludge, developed by the authors during research into the sludge collected from the scrubber of a PV cell manufacturing plant located in southern Italy. Full article

(This article belongs to the Section Energy Systems)

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27 pages, 10640 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Practice-Oriented Validation of Embedded Beam Formulations in Geotechnical Engineering

by Andreas-Nizar Granitzer and Franz Tschuchnigg

Processes 2021, 9(10), 1739; https://doi.org/10.3390/pr9101739 - 28 Sep 2021

Cited by 11 | Viewed by 4140

Abstract

The numerical analysis of many geotechnical problems involves a high number of structural elements, leading to extensive modelling and computational effort. Due to its exceptional ability to circumvent these obstacles, the embedded beam element (EB), though originally intended for the modelling of micropiles, [...] Read more.

The numerical analysis of many geotechnical problems involves a high number of structural elements, leading to extensive modelling and computational effort. Due to its exceptional ability to circumvent these obstacles, the embedded beam element (EB), though originally intended for the modelling of micropiles, has become increasingly popular in computational geotechnics. Recent research effort has paved the way to the embedded beam element with interaction surface (EB-I), an extension of the EB. The EB-I renders soil–structure interaction along an interaction surface rather than the centreline, making it theoretically applicable to any engineering application where beam-type elements interact with solid elements. At present, in-depth knowledge about relative merits, compared to the EB, is still in demand. Subsequently, numerical analysis are carried out using both embedded beam formulations to model deep foundation elements. The credibility of predicted results is assessed based on a comprehensive comparison with the well-established standard FE approach. In all cases considered, the EB-I proves clearly superior in terms of mesh sensitivity, mobilization of skin-resistance, and predicted soil displacements. Special care must be taken when using embedded beam formulations for the modelling of composite structures. Full article

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

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14 pages, 1328 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Hydroxyapatite Precipitation and Accumulation in Granules and Its Effects on Activity and Stability of Partial Nitrifying Granules at Moderate and High Temperatures

by Yong-Qiang Liu and Simone Cinquepalmi

Processes 2021, 9(10), 1710; https://doi.org/10.3390/pr9101710 - 24 Sep 2021

Cited by 7 | Viewed by 2353

Abstract

Precipitation and accumulation of calcium phosphate in granular sludge has attracted research attention recently for phosphate removal and recovery from wastewater. This study investigated calcium phosphate accumulation from granulation stage to steady state by forming heterotrophic granules at different COD/N ratios at 21 [...] Read more.

Precipitation and accumulation of calcium phosphate in granular sludge has attracted research attention recently for phosphate removal and recovery from wastewater. This study investigated calcium phosphate accumulation from granulation stage to steady state by forming heterotrophic granules at different COD/N ratios at 21 and 32 °C, respectively, followed by the transformation of heterotrophic granules to partial nitrifying granules. It was found that mature granules accumulated around 60–80% minerals in granules, much higher than young granules with only around 30% ash contents. In addition, high temperature promoted co-precipitation of hydroxyapatite and calcite in granules with more calcite than hydroxyapatite and only 4.1% P content, while mainly hydroxyapatite was accumulated at the moderate temperature with 7.7% P content. The accumulation of minerals in granules at the high temperature with 75–80% ash content also led to the disintegration and instability of granules. Specific ammonium oxidation rates were reduced, as well, from day 58 to day 121 at both temperatures due to increased mineral contents. These results are meaningful to control or manipulate granular sludge for phosphorus removal and recovery by forming and accumulating hydroxyapatite in granules, as well as for the maintenance of microbial activities of granules. Full article

(This article belongs to the Special Issue Environmental Protection by Aerobic Granular Sludge Process)

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20 pages, 22674 KiB

Open AccessEditor’s ChoiceArticle

Development and Optimization of Chitosan-Hydroxypropyl Methylcellulose In Situ Gelling Systems for Ophthalmic Delivery of Bupivacaine Hydrochloride

by Lăcrămioara Popa, Mihaela Violeta Ghica, Roxana Popescu, Teodora Irimia and Cristina-Elena Dinu-Pîrvu

Processes 2021, 9(10), 1694; https://doi.org/10.3390/pr9101694 - 22 Sep 2021

Cited by 11 | Viewed by 3222

Abstract

The aim of this study was the development and optimization of chitosan and hydroxypropyl methylcellulose (HPMC) in situ gelling systems, loaded with bupivacaine hydrochloride for topical ocular administration. This study is based on the properties of two polymers: chitosan, which has mucoadhesive action [...] Read more.

The aim of this study was the development and optimization of chitosan and hydroxypropyl methylcellulose (HPMC) in situ gelling systems, loaded with bupivacaine hydrochloride for topical ocular administration. This study is based on the properties of two polymers: chitosan, which has mucoadhesive action and is a pH-sensitive polymer, but also the cellulose derivative hydroxypropyl methylcellulose, a thermosensitive polymer which has mucoadhesive properties and increases the viscosity of systems. The analysis and optimization of in situ gelling systems were performed based on an experimental design and response surface methodology. The following formulation parameters were considered: X₁ = chitosan concentration (0.5%, 1%), X₂ = HPMC E 5 LV concentration (2%, 5%) and X₃ = Chitosan/HPMC E 5 LV ratio (1/1, 2/1). In addition, the parameters to be optimized were represented by the contact angle (CA (°)), viscosity and cumulative percentage of bupivacaine hydrochloride released in vitro. The results indicate that the designed in situ gelling systems are suitable for bupivacaine prolonged ophthalmic release and overcome the principal disadvantages of the liquid’s ocular formulations. An immediate therapeutic effect corresponding to ocular anesthetic installation was assured in the first stage: burst bupivacaine release. In the second phase, the gradual drug release was assured for over 6 h. This drug release profile, together with the corresponding rheological profile and a collection of superficial properties for good ocular adhesion balanced with an adequate hydrophilic character, assured the desired quality of the attributes for the proposed systems. The system, based on chitosan 1%, HPMC E 5 LV 5% and a 1/1 polymer ratio, could be a solution for the proposed formulation of in situ gelling colloidal systems, since the viscosity of the system was within the range of the optimal viscosity of the eye, and the amount of bupivacaine hydrochloride released after 6 h was the highest at 69.55%. Full article

(This article belongs to the Special Issue Pharmaceutical Development and Bioavailability Analysis)

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15 pages, 1858 KiB

Open AccessEditor’s ChoiceArticle

Effect of Pulse Type and Substitution Level on Dough Rheology and Bread Quality of Whole Wheat-Based Composite Flours

by Yiqin Zhang, Ruijia Hu, Michael Tilley, Kaliramesh Siliveru and Yonghui Li

Processes 2021, 9(9), 1687; https://doi.org/10.3390/pr9091687 - 21 Sep 2021

Cited by 19 | Viewed by 4071

Abstract

Pulse flours are commonly added to food products to improve the functional properties, nutritional profiles, product quality and health benefits. This study aimed at assessing the effects of the partial replacement (0–25%) of whole wheat flour with diversified whole pulse flours (yellow pea, [...] Read more.

Pulse flours are commonly added to food products to improve the functional properties, nutritional profiles, product quality and health benefits. This study aimed at assessing the effects of the partial replacement (0–25%) of whole wheat flour with diversified whole pulse flours (yellow pea, green pea, red lentil, and chickpea) on dough properties and bread quality. The pulse flours had higher protein contents and ash, but lower moisture content and larger average particle size, compared to whole wheat flour. Increasing the substitution level of pulse flours decreased dough viscosity, stability, development time and bread volume, and accelerated bread retrogradation. The incorporation of 5% yellow pea flour led to a similar bread quality as that with only whole wheat flour. Among all the tested pulse flours, the composite flour containing yellow pea flour or chickpea flour had overall better potential for bread making by providing good dough handling properties and product quality. This study will benefit the development of more nutritious food products by combining cereal and pulse ingredients. Full article

(This article belongs to the Special Issue Processing and Properties Analysis of Grain Foods)

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14 pages, 9779 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Reactive Chromatography Applied to Ethyl Levulinate Synthesis: A Proof of Concept

by Carmelina Rossano, Claudio Luigi Pizzo, Riccardo Tesser, Martino Di Serio and Vincenzo Russo

Processes 2021, 9(9), 1684; https://doi.org/10.3390/pr9091684 - 20 Sep 2021

Cited by 5 | Viewed by 2736

Abstract

Levulinic acid (LA) has been highlighted as one of the most promising platform chemicals, providing a wide range of possible derivatizations to value-added chemicals as the ethyl levulinate obtained through an acid catalyzed esterification reaction with ethanol that has found application in the [...] Read more.

Levulinic acid (LA) has been highlighted as one of the most promising platform chemicals, providing a wide range of possible derivatizations to value-added chemicals as the ethyl levulinate obtained through an acid catalyzed esterification reaction with ethanol that has found application in the bio-fuel market. Being a reversible reaction, the main drawback is the production of water that does not allow full conversion of levulinic acid. The aim of this work was to prove that the chromatographic reactor technology, in which the solid material of the packed bed acts both as stationary phase and catalyst, is surely a valid option to overcome such an issue by overcoming the thermodynamic equilibrium. The experiments were conducted in a fixed-bed chromatographic reactor, packed with Dowex 50WX-8 as ion exchange resin. Different operational conditions were varied (e.g., temperature and flow rate), pulsing levulinic acid to the ethanol stream, to investigate the main effects on the final conversion and separation efficiency of the system. The effects were described qualitatively, demonstrating that working at sufficiently low flow rates, LA was completely converted, while at moderate flow rates, only a partial conversion was achieved. The system worked properly even at room temperature (303 K), where LA was completely converted, an encouraging result as esterification reactions are normally performed at higher temperatures. Full article

(This article belongs to the Special Issue Process Intensification in Chemical Reaction Engineering)

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23 pages, 377 KiB

Open AccessFeature PaperEditor’s ChoiceReview

The Quality of Horsemeat and Selected Methods of Improving the Properties of This Raw Material

by Renata Stanisławczyk, Mariusz Rudy and Stanisław Rudy

Processes 2021, 9(9), 1672; https://doi.org/10.3390/pr9091672 - 17 Sep 2021

Cited by 12 | Viewed by 6681

Abstract

Horsemeat has a strictly defined group of consumers whose demand varies depending on the country or region. There is no tradition of consuming horsemeat in Poland. From a technological point of view, this raw material is as good as other types of meat. [...] Read more.

Horsemeat has a strictly defined group of consumers whose demand varies depending on the country or region. There is no tradition of consuming horsemeat in Poland. From a technological point of view, this raw material is as good as other types of meat. In the opinion of the consumer, compared to other species of animals, horsemeat is characterized by an intense red-brown colour and greater cohesiveness resulting from the type of muscle fibres. This meat has a sweetish taste due to the high carbohydrate content. The management of horsemeat often involves the use of modern freezing methods. Freezing horsemeat with the use of liquefied carbon dioxide is a method that increases its suitability for consumption as well as for export purposes in comparison with the traditional air-cooling method. To eliminate the unfavourable quality features of horsemeat, there are substances used to improve the functional and sensory properties of this meat. This paper discusses the research and development work carried out in the field of horsemeat quality and selected methods contributing to its improvement. Full article

(This article belongs to the Special Issue Feature Review Papers in Section "Food Processes")

19 pages, 2888 KiB

Open AccessEditor’s ChoiceArticle

Kinetics of Cometabolic Transformation of 4-chlorophenol and Phenol Degradation by Pseudomonas putida Cells in Batch and Biofilm Reactors

by Yen-Hui Lin

Processes 2021, 9(9), 1663; https://doi.org/10.3390/pr9091663 - 15 Sep 2021

Cited by 4 | Viewed by 1973

Abstract

The biodegradation kinetics of 4-chlorophenol (4-CP) and phenol and microbial growth of Pseudomonas putida (P. putida) cells were estimated in batch and biofilm reactors. The kinetic parameters of cells on phenol were determined using the Haldane formula. The maximum specific growth [...] Read more.

The biodegradation kinetics of 4-chlorophenol (4-CP) and phenol and microbial growth of Pseudomonas putida (P. putida) cells were estimated in batch and biofilm reactors. The kinetic parameters of cells on phenol were determined using the Haldane formula. The maximum specific growth rate of P. putida on phenol, the half-saturation constant of phenol and the self-inhibition constant of phenol were 0.512 h⁻¹, 78.38 mg/L and 228.5 mg/L, respectively. The yield growth of cells on phenol (Y_P) was 0.618 mg phenol/mg cell. The batch experimental results for the specific transformation rate of 4-CP by resting P. putida cells were fitted with Haldane kinetics to evaluate the maximum specific utilization rate of 4-CP, half-saturation constant of 4-CP, and self-inhibition constant of 4-CP, which were 0.246 h⁻¹, 1.048 mg/L and 53.40 mg/L, respectively. The negative specific growth rates of cells on 4-CP obtained were fitted using a kinetic equation to investigate the true transformation capacity and first-order endogenous decay coefficient, which were 4.34 mg 4-CP/mg cell and 5.99 × 10⁻³ h⁻¹, respectively. The competitive inhibition coefficients of phenol to 4-CP transformation and 4-CP to phenol degradation were 6.75 and 9.27 mg/L, respectively; therefore, phenol had a higher competitive inhibition of 4-CP transformation than the converse. The predicted model examining cometabolic transformation of 4-CP and phenol degradation showed good agreement with the experimental observations. The removal efficiencies for phenol and 4-CP were 94.56–98.45% and 96.09–98.85%, respectively, for steady-state performance. Full article

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21 pages, 5477 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Biomolecular Modifications Linked to Oxidative Stress in Amyotrophic Lateral Sclerosis: Determining Promising Biomarkers Related to Oxidative Stress

by Takashi Hosaka, Hiroshi Tsuji and Akira Tamaoka

Processes 2021, 9(9), 1667; https://doi.org/10.3390/pr9091667 - 15 Sep 2021

Cited by 8 | Viewed by 3614

Abstract

Reduction–oxidation reactions are essential to cellular homeostasis. Oxidative stress transcends physiological antioxidative system damage to biomolecules, including nucleic acids and proteins, and modifies their structures. Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease. The cells present in the central [...] Read more.

Reduction–oxidation reactions are essential to cellular homeostasis. Oxidative stress transcends physiological antioxidative system damage to biomolecules, including nucleic acids and proteins, and modifies their structures. Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease. The cells present in the central nervous system, including motor neurons, are vulnerable to oxidative stress. Neurodegeneration has been demonstrated to be caused by oxidative biomolecular modifications. Oxidative stress has been suggested to be involved in the pathogenesis of ALS. Recent progress in research on the underlying mechanisms of oxidative stress in ALS has led to the development of disease-modifying therapies, including edaravone. However, the clinical effects of edaravone remain limited, and ALS is a heretofore incurable disease. The reason for the lack of reliable biomarkers and the precise underlying mechanisms between oxidative stress and ALS remain unclear. As extracellular proteins and RNAs present in body fluids and represent intracellular pathological neurodegenerative processes, extracellular proteins and/or RNAs are predicted to promise diagnosis, prediction of disease course, and therapeutic biomarkers for ALS. Therefore, we aimed to elucidate the underlying mechanisms between oxidative stress and ALS, and promising biomarkers indicating the mechanism to determine whether therapy targeting oxidative stress can be fundamental for ALS. Full article

(This article belongs to the Special Issue Advances of Redox Status in Disease)

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13 pages, 2796 KiB

Open AccessEditor’s ChoiceArticle

Reduction of Volatile Organic Compounds (VOCs) Emissions from Laundry Dry-Cleaning by an Integrated Treatment Process of Condensation and Adsorption

by Mugeun Song, Kyunghoon Kim, Changmin Cho and Daekeun Kim

Processes 2021, 9(9), 1658; https://doi.org/10.3390/pr9091658 - 14 Sep 2021

Cited by 18 | Viewed by 3963

Abstract

Volatile organic compounds (VOCs) are intermittently emitted at high concentrations (tens of thousands of ppmv) from small-scale laundry shops in urban areas, affecting the urban atmospheric environment. In this study, we suggested integrating VOC treatment processes incorporating condensation and adsorption in series to [...] Read more.

Volatile organic compounds (VOCs) are intermittently emitted at high concentrations (tens of thousands of ppmv) from small-scale laundry shops in urban areas, affecting the urban atmospheric environment. In this study, we suggested integrating VOC treatment processes incorporating condensation and adsorption in series to remove VOCs released from small-scale laundry dryers (laundry weighing less than 30 kg). We designed two different processes depending on regeneration modes for adsorber beds; an open-circuit flow process and a closed-loop flow process in regeneration mode. Our VOC treatment processes enable sustainable operation via the regeneration of adsorbers on a regular basis. Before applying the VOC treatment processes, average concentration of total volatile organic compounds (TVOCs) was 4099 ppmv (12,000 ppmv of the peak concentration) during the drying operation. After applying our closed-loop flow process, TVOC concentration decreased to 58 ppmv, leading to 98.5% removal efficiency. We also verified the robustness of our process performance in a continuous operation (30 cycles) by using a process simulation program. Lastly, we observed that our integrated treatment process can contribute to reductions in ozone and secondary organic aerosol generation by 90.4% and 95.9%, respectively. We concluded that our integrated VOC treatment processes are applicable to small-scale laundry shops releasing high-concentration VOCs intermittently, and are beneficial to the atmospheric environment. Full article

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

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17 pages, 474 KiB

Open AccessEditor’s ChoiceReview

Roles of Drying, Size Reduction, and Blanching in Sustainable Extraction of Phenolics from Olive Leaves

by Fereshteh Safarzadeh Markhali

Processes 2021, 9(9), 1662; https://doi.org/10.3390/pr9091662 - 14 Sep 2021

Cited by 9 | Viewed by 4576

Abstract

It is now known that olive leaves contain a sizable portion of polyphenols and there is much research highlighting that these natural ingredients favorably exhibit bio-functional activities. In this regard, many studies have focused on the exploration of optimum conditions involved directly in [...] Read more.

It is now known that olive leaves contain a sizable portion of polyphenols and there is much research highlighting that these natural ingredients favorably exhibit bio-functional activities. In this regard, many studies have focused on the exploration of optimum conditions involved directly in the extraction process. These investigations, while being highly valuable, may somewhat cast a shadow over other contributing factors such as those involved in the preprocessing of leaves, including size reduction, drying, and blanching. The use of these unit operations under appropriate conditions, together with other benefits, potentially exert improved surface area, homogeneity, and diffusion/mass transfer which may help develop the liberation of target bio-compounds. The research work in this area, particularly size reduction, is relatively limited. Although in various experiments they are incorporated, not many studies have focused on them as the main predictor variables. The performance of further research may help ascertain the magnitude of their effects. Consideration of the operational parameters in preprocessing step is equally important as those in the processing/extraction step that may comparably influence on the extraction efficiency. This review provides an overview of the potential roles of drying, size reduction, and blanching in the extraction efficiency of phenolics from olive leaves. Full article

(This article belongs to the Special Issue Sustainable Development of Waste towards Green Growth)

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17 pages, 1015 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Bladder Substitution: The Role of Tissue Engineering and Biomaterials

by Martina Casarin, Alessandro Morlacco and Fabrizio Dal Moro

Processes 2021, 9(9), 1643; https://doi.org/10.3390/pr9091643 - 13 Sep 2021

Cited by 14 | Viewed by 3538

Abstract

Tissue engineering could play a major role in the setting of urinary diversion. Several conditions cause the functional or anatomic loss of urinary bladder, requiring reconstructive procedures on the urinary tract. Three main approaches are possible: (i) incontinent cutaneous diversion, such as ureterocutaneostomy, [...] Read more.

Tissue engineering could play a major role in the setting of urinary diversion. Several conditions cause the functional or anatomic loss of urinary bladder, requiring reconstructive procedures on the urinary tract. Three main approaches are possible: (i) incontinent cutaneous diversion, such as ureterocutaneostomy, colonic or ileal conduit, (ii) continent pouch created using different segments of the gastrointestinal system and a cutaneous stoma, and (iii) orthotopic urinary diversion with an intestinal segment with spherical configuration and anastomosis to the urethra (neobladder, orthotopic bladder substitution). However, urinary diversions are associated with numerous complications, such as mucus production, electrolyte imbalances and increased malignant transformation potential. In this context, tissue engineering would have the fundamental role of creating a suitable material for urinary diversion, avoiding the use of bowel segments, and reducing complications. Materials used for the purpose of urinary substitution are biological in case of acellular tissue matrices and naturally derived materials, or artificial in case of synthetic polymers. However, only limited success has been achieved so far. The aim of this review is to present the ideal properties of a urinary tissue engineered scaffold and to examine the results achieved so far. The most promising studies have been highlighted in order to guide the choice of scaffolds and cells type for further evolutions. Full article

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

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13 pages, 4853 KiB

Open AccessEditor’s ChoiceArticle

Effects of Geniposide and Geniposidic Acid on Fluoxetine-Induced Muscle Atrophy in C2C12 Cells

by Shang-Ming Huang, Shuan-Ying Lin, Ming-Kai Chen, Chiung-Chi Peng and Chiu-Lan Hsieh

Processes 2021, 9(9), 1649; https://doi.org/10.3390/pr9091649 - 13 Sep 2021

Cited by 2 | Viewed by 2662

Abstract

Fluoxetine, an antidepressant known as a selective 5-hydroxytryptamine reuptake inhibitor (SSRI), can cause side effects such as muscle atrophy with long-term use, but the mechanism is not fully understood. Geniposide (GPS) and geniposidic acid (GPSA), the main components of Gardenia jasminoides fruit, have [...] Read more.

Fluoxetine, an antidepressant known as a selective 5-hydroxytryptamine reuptake inhibitor (SSRI), can cause side effects such as muscle atrophy with long-term use, but the mechanism is not fully understood. Geniposide (GPS) and geniposidic acid (GPSA), the main components of Gardenia jasminoides fruit, have been shown to have biological activity in disease prevention, but their role in preventing FXT-related side effects such as muscle atrophy remains unclear. The process of muscle atrophy is a complex physiological mechanism involving the balance of protein synthesis and catabolism. In this study, we hypothesized that FXT may suppress hypertrophy signaling and activate the atrophy mechanisms, resulting in proteolysis and reduced protein synthesis, while geniposide (GPS) and geniposide acid (GPSA) may be beneficial in improving muscle weakness caused by FXT. The C2C12 cell model was used to examine the expression of hypertrophy signaling (PI3K, Akt, and mTOR) and protein break signals (FOXO, MuRF-1, and MyHC). Our data indicated that FXT inhibited MyHC and promoted MuRF-1 protein expression by downregulating the signaling pathways of p-ERK1/2, p-Akt, p-mTOR, and p-FOXO, resulting in a decrease in differentiation and myotube formation in C2C12 muscle cells, which further resulted in muscle atrophy. However, GPS and GPSA can positively regulate the atrophy mechanism induced by FXT in muscle cells, thereby ameliorating the imbalance in muscle synthesis. In conclusion, GPS and GPSA have the potential to attenuate the muscle loss caused by long-term FXT administration, diseases, or the aging process. Full article

(This article belongs to the Special Issue Food Safety Management and Quality Control Techniques)

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14 pages, 7064 KiB

Open AccessEditor’s ChoiceArticle

Preparation of Microcellular Foams by Supercritical Carbon Dioxide: A Case Study of Thermoplastic Polyurethane 70A

by Yu-Ting Hsiao, Chieh-Ming Hsieh, Tsung-Mao Yang and Chie-Shaan Su

Processes 2021, 9(9), 1650; https://doi.org/10.3390/pr9091650 - 13 Sep 2021

Cited by 4 | Viewed by 2542

Abstract

In this study, a case study to produce microcellular foam of a commercial thermoplastic polyurethane (TPU) through the supercritical carbon dioxide (CO₂) foaming process is presented. To explore the feasibility of TPU in medical device and biomedical application, a soft TPU [...] Read more.

In this study, a case study to produce microcellular foam of a commercial thermoplastic polyurethane (TPU) through the supercritical carbon dioxide (CO₂) foaming process is presented. To explore the feasibility of TPU in medical device and biomedical application, a soft TPU with Shore hardness value of 70A was selected as the model compound. The effects of saturation temperature and saturation pressure ranging from 90 to 140 °C and 90 to 110 bar on the expansion ratio, cell size and cell density of the TPU foam were compared and discussed. Regarding the expansion ratio, the effect of saturation temperature was considerable and an intermediate saturation temperature of 100 °C was favorable to produce TPU microcellular foam with a high expansion ratio. On the other hand, the mean pore size and cell density of TPU foam can be efficiently manipulated by adjusting the saturation pressure. A high saturation pressure was beneficial to obtain TPU foam with small mean pore size and high cell density. This case study shows that the expansion ratio of TPU microcellular foam could be designed as high as 4.4. The cell size and cell density could be controlled within 12–40 μm and 5.0 × 10⁷–1.3 × 10⁹ cells/cm³, respectively. Full article

(This article belongs to the Special Issue Advanced Polymer Processing Processes)

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15 pages, 6653 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Automated Compartment Model Development Based on Data from Flow-Following Sensor Devices

by Jonas Bisgaard, Tannaz Tajsoleiman, Monica Muldbak, Thomas Rydal, Tue Rasmussen, Jakob K. Huusom and Krist V. Gernaey

Processes 2021, 9(9), 1651; https://doi.org/10.3390/pr9091651 - 13 Sep 2021

Cited by 8 | Viewed by 2632

Abstract

Due to the heterogeneous nature of large-scale fermentation processes they cannot be modelled as ideally mixed reactors, and therefore flow models are necessary to accurately represent the processes. Computational fluid dynamics (CFD) is used more and more to derive flow fields for the [...] Read more.

Due to the heterogeneous nature of large-scale fermentation processes they cannot be modelled as ideally mixed reactors, and therefore flow models are necessary to accurately represent the processes. Computational fluid dynamics (CFD) is used more and more to derive flow fields for the modelling of bioprocesses, but the computational demands associated with simulation of multiphase systems with biokinetics still limits their wide applicability. Hence, a demand for simpler flow models persists. In this study, an approach to develop data-based flow models in the form of compartment models is presented, which utilizes axial-flow rates obtained from flow-following sensor devices in combination with a proposed procedure for automatic zoning of volume. The approach requires little experimental effort and eliminates the necessity for computational determination of inter-compartmental flow rates and manual zoning. The concept has been demonstrated in a 580 L stirred vessel, of which models have been developed for two types of impellers with varying agitation intensities. The sensor device measurements were corroborated by CFD simulations, and the performance of the developed compartment models was evaluated by comparing predicted mixing times with experimentally determined mixing times. The data-based compartment models predicted the mixing times for all examined conditions with relative errors in the range of 3–27%. The deviations were ascribed to limitations in the flow-following behavior of the sensor devices, whose sizes were relatively large compared to the examined system. The approach provides a versatile and automated flow modelling platform which can be applied to large-scale bioreactors. Full article

(This article belongs to the Special Issue Bioreactor System: Design, Modeling and Continuous Production Process)

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17 pages, 13161 KiB

Open AccessEditor’s ChoiceArticle

Photovoltaic Module Fault Detection Based on a Convolutional Neural Network

by Shiue-Der Lu, Meng-Hui Wang, Shao-En Wei, Hwa-Dong Liu and Chia-Chun Wu

Processes 2021, 9(9), 1635; https://doi.org/10.3390/pr9091635 - 10 Sep 2021

Cited by 13 | Viewed by 3317

Abstract

With the rapid development of solar energy, the photovoltaic (PV) module fault detection plays an important role in knowing how to enhance the reliability of the solar photovoltaic system and knowing the fault type when a system problem occurs. Therefore, this paper proposed [...] Read more.

With the rapid development of solar energy, the photovoltaic (PV) module fault detection plays an important role in knowing how to enhance the reliability of the solar photovoltaic system and knowing the fault type when a system problem occurs. Therefore, this paper proposed the hybrid algorithm of chaos synchronization detection method (CSDM) with convolutional neural network (CNN) for studying PV module fault detection. Four common PV module states were discussed, including the normal PV module, module breakage, module contact defectiveness and module bypass diode failure. First of all, the defects in 16 pieces of 20W monocrystalline silicon PV modules were preprocessed, and there were four pieces of each fault state. When the signal generator delivered high frequency voltage to the PV module, the original signal was measured and captured by the NI PXI-5105 high-speed data acquisition system (DAS) and was calculated by CSDM, to establish the chaos dynamic error map as the image feature of fault diagnosis. Finally, the CNN was employed for diagnosing the fault state of the PV module. The findings show that after entering 400 random fault data (100 data for each fault) into the proposed method for recognition, the recognition accuracy rate of the proposed method was as high as 99.5%, which is better than the traditional ENN algorithm that had a recognition rate of 86.75%. In addition, the advantage of the proposed algorithm is that the mass original measured data can be reduced by CSDM, the subtle changes in the output signals are captured effectively and displayed in images, and the PV module fault state is accurately recognized by CNN. Full article

(This article belongs to the Special Issue Application of Power Electronics Technologies in Power System)

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18 pages, 5408 KiB

Open AccessEditor’s ChoiceArticle

Data Driven Detection of Different Dissolved Oxygen Sensor Faults for Improving Operation of the WWTP Control System

by Alexandra-Veronica Luca, Melinda Simon-Várhelyi, Norbert-Botond Mihály and Vasile-Mircea Cristea

Processes 2021, 9(9), 1633; https://doi.org/10.3390/pr9091633 - 10 Sep 2021

Cited by 11 | Viewed by 2946

Abstract

Sensor faults frequently occur in wastewater treatment plant (WWTP) operation, leading to incomplete monitoring or poor control of the plant. Reliable operation of the WWTP considerably depends on the aeration control system, which is essentially assisted by the dissolved oxygen (DO) sensor. Results [...] Read more.

Sensor faults frequently occur in wastewater treatment plant (WWTP) operation, leading to incomplete monitoring or poor control of the plant. Reliable operation of the WWTP considerably depends on the aeration control system, which is essentially assisted by the dissolved oxygen (DO) sensor. Results on the detection of different DO sensor faults, such as bias, drift, wrong gain, loss of accuracy, fixed value, or complete failure, were investigated based on Principal Components Analysis (PCA). The PCA was considered together with two statistical approaches, i.e., the Hotelling’s T² and the Squared Prediction Error (SPE). Data used in the study were generated using the previously calibrated first-principle Activated Sludge Model no.1 for the Anaerobic-Anoxic-Oxic (A²O) reactors configuration. The equation-based model was complemented with control loops for DO concentration control in the aerobic reactor and nitrates concentration control in the anoxic reactor. The PCA data-driven model was successfully used for the detection of the six investigated DO sensor faults. The statistical detection approaches were compared in terms of promptness, effectiveness, and accuracy. The obtained results revealed the way faults originating from DO sensor malfunction can be detected and the efficiency of the detection approaches for the automatically controlled WWTP. Full article

(This article belongs to the Special Issue Treatment and Utilization of Waste Materials)

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14 pages, 667 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Potential for Lager Beer Production from Saccharomyces cerevisiae Strains Isolated from the Vineyard Environment

by Massimo Iorizzo, Francesco Letizia, Gianluca Albanese, Francesca Coppola, Angelita Gambuti, Bruno Testa, Riccardo Aversano, Martino Forino and Raffaele Coppola

Processes 2021, 9(9), 1628; https://doi.org/10.3390/pr9091628 - 9 Sep 2021

Cited by 10 | Viewed by 4565

Abstract

Saccharomyces pastorianus, genetic hybrids of Saccharomyces cerevisiae and the Saccharomyces eubayanus, is one of the most widely used lager yeasts in the brewing industry. In recent years, new strategies have been adopted and new lines of research have been outlined to [...] Read more.

Saccharomyces pastorianus, genetic hybrids of Saccharomyces cerevisiae and the Saccharomyces eubayanus, is one of the most widely used lager yeasts in the brewing industry. In recent years, new strategies have been adopted and new lines of research have been outlined to create and expand the pool of lager brewing starters. The vineyard microbiome has received significant attention in the past few years due to many opportunities in terms of biotechnological applications in the winemaking processes. However, the characterization of S. cerevisiae strains isolated from winery environments as an approach to selecting starters for beer production has not been fully investigated, and little is currently available. Four wild cryotolerant S. cerevisiae strains isolated from vineyard environments were evaluated as potential starters for lager beer production at laboratory scale using a model beer wort (MBW). In all tests, the industrial lager brewing S. pastorianus Weihenstephan 34/70 was used as a reference strain. The results obtained, although preliminary, showed some good properties of these strains, such as antioxidant activity, flocculation capacity, efficient fermentation at 15 °C and low diacetyl production. Further studies will be carried out using these S. cerevisiae strains as starters for lager beer production on a pilot scale in order to verify the chemical and sensory characteristics of the beers produced. Full article

(This article belongs to the Special Issue Control and Optimization of Alcoholic Fermentation and Extraction Technology)

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