Processes

12 pages, 3945 KiB

Open AccessArticle

Surface Roughness Prediction and Optimization in the Orthogonal Cutting of Graphite/Polymer Composites Based on Artificial Neural Network

by Dayong Yang, Qingda Guo, Zhenping Wan, Zhiqing Zhang and Xiaofang Huang

Processes 2021, 9(10), 1858; https://doi.org/10.3390/pr9101858 - 19 Oct 2021

Cited by 9 | Viewed by 1949

Abstract

Graphite/polymer composites are brittle materials that are prone to producing cracks and concavities on machined surfaces, and their surface quality shows greater randomness. This work aims to overcome the large fluctuations in the machined surface quality of graphite/polymer composites, realize the prediction of [...] Read more.

Graphite/polymer composites are brittle materials that are prone to producing cracks and concavities on machined surfaces, and their surface quality shows greater randomness. This work aims to overcome the large fluctuations in the machined surface quality of graphite/polymer composites, realize the prediction of machined surface roughness under different machining conditions and optimize the process parameters. A graphite/polymer composite material was cut orthogonally using different machining parameters, and the machined surface roughness of the cut samples was measured by a noncontact surface profiler to obtain training samples for Artificial Neural Network (ANN). In this study, a trained radial basis function neural network was used to predict the machined surface roughness, and the prediction accuracy was more than 93%. A Genetic Algorithm (GA) was used to optimize the established ANN, and then grey relational analysis was used to compare the accuracy of the GA optimization results. The ANN prediction after GA optimization showed that the lowest machined surface roughness of the graphite/polymer composites was 1.81 μm, and the corresponding optimal cutting speed, cutting depth, tool rake angle, and rounded edge radius were 11.2 m/min, 0.1 mm, 6.85°, and 11.16 μm, respectively. A verification experiment showed that the lowest machined surface roughness was obtained when the above process parameters were selected, which was only 1.95 μm, and the prediction error of the ANN was approximately 7%. The combination of a GA and an ANN can accurately predict the surface roughness of graphite/polymer composite materials and optimize the process parameters. Full article

(This article belongs to the Section Materials Processes)

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11 pages, 53920 KiB

Open AccessArticle

Interfacial Microstructure Analysis of AZ31 Magnesium Alloy during Plastic Deformation Bonding

by Limei Ren, Bei Li, Zhaoxiang Chen, Shan Gao, Yongqiang Quan and Lihe Qian

Processes 2021, 9(10), 1857; https://doi.org/10.3390/pr9101857 - 19 Oct 2021

Cited by 3 | Viewed by 1658

Abstract

In this study, a plastic deformation process consisting of hot compression at 350 °C and heat treatment at 400 °C was performed to bond AZ31 magnesium alloy. Microstructural evolution around the bonding interface was systematically characterized to investigate the bonding process and clarify [...] Read more.

In this study, a plastic deformation process consisting of hot compression at 350 °C and heat treatment at 400 °C was performed to bond AZ31 magnesium alloy. Microstructural evolution around the bonding interface was systematically characterized to investigate the bonding process and clarify the bonding mechanism. When the plastic deformation strain reached 0.6, the bonding zone was full of fine dynamic recrystallized grains and the initial interface was eliminated. The post-heating treatments were conducted to achieve a sound interface bonding. The tensile tests and the corresponding fracture morphologies analysis indicated that the optimum holding time of heat treatment was 8 h. The interfacial bonding strength of the specimens holding for 8 h reached 164.7 MPa, an enhancement of about 9% compared with that of the specimens holding for 1 h. The microstructure analysis indicated that the bonding quality was affected by migration of the interfacial grain boundary (GB), the development of recrystallized grains and the evolution of interfacial oxides around the bonding area. Full article

(This article belongs to the Section Materials Processes)

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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 2028

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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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 2476

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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14 pages, 1321 KiB

Open AccessArticle

Energy Flexibility Chances for the Wastewater Treatment Plant of the Benchmark Simulation Model 1

by George Skouteris, Mario Alejandro Parra Ramirez, Sebastian Felix Reinecke and Uwe Hampel

Processes 2021, 9(10), 1854; https://doi.org/10.3390/pr9101854 - 19 Oct 2021

Cited by 2 | Viewed by 2471

Abstract

Future energy systems must mainly generate electricity from renewable resources. To deal with the fluctuating availability of wind and solar power, new versatile electricity markets and sustainable solutions concentrating on energy flexibility are needed. In this research, we investigated the potential of energy [...] Read more.

Future energy systems must mainly generate electricity from renewable resources. To deal with the fluctuating availability of wind and solar power, new versatile electricity markets and sustainable solutions concentrating on energy flexibility are needed. In this research, we investigated the potential of energy flexibility achieved through demand-side response for the wastewater treatment plant of the Benchmark Simulation Model 1. First, seven control strategies were simulated and assessed. Next, the flexibility calls were identified, two energy flexibility scenarios were defined and incorporated into the model, and the control strategies were evaluated anew. In this research, the effluent ammonia concentration needed to be maintained within the limits for as long as possible. Strategy 5, which controlled ammonia in Tank 5 at a low value and did not control any nitrate in Tank 2, of Scenario 1, which was characterized by an undetermined on/off aeration cycle, was then found to be the best. Although this control strategy led to high total energy consumption, the percentage of time during which aeration was nearly suspended was one of the highest. This work proposes a methodology that will be useful to plant operators who should soon reduce energy consumption during spikes in electricity prices. Full article

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

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10 pages, 1789 KiB

Open AccessArticle

Optimization of Compression Molding Process Parameters for NFPC Manufacturing Using Taguchi Design of Experiment and Moldflow Analysis

by Vardaan Chauhan, Timo Kärki and Juha Varis

Processes 2021, 9(10), 1853; https://doi.org/10.3390/pr9101853 - 19 Oct 2021

Cited by 10 | Viewed by 4645

Abstract

This paper presents the application of Taguchi design of experiment and Autodesk Moldflow^® simulation in finding the optimal processing parameters for the manufacturing of natural fiber–polymer composite products. The material used in the study is a composite of recycled thermoplastic reinforced with [...] Read more.

This paper presents the application of Taguchi design of experiment and Autodesk Moldflow^® simulation in finding the optimal processing parameters for the manufacturing of natural fiber–polymer composite products. The material used in the study is a composite of recycled thermoplastic reinforced with 10% wood fibers. For the study, four critical processing parameters, namely compression time, mold temperature, melt temperate, and pressure, were selected for optimization. Process analysis was carried out in Moldflow^® utilizing a combination of process parameters based on an L9 orthogonal array. Later, the warpage output from Moldflow^® simulation was converted into a signal-to-noise (S/N) ratio response, and the optimum values of each processing parameter were obtained using the smaller-the-better quality characteristic. The results show that the optimum values were 60 °C, 40 s, 210 °C, and 600 kN for the mold temperature, compression time, melt temperature, and pressure, respectively. Afterward, a confirmation test was performed to test the optimum parameters. Using analysis of variance (ANOVA), melt temperature was found to be the most significant processing parameter, followed by mold temperature, compression time, and pressure. Full article

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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 2213

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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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 5236

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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14 pages, 4447 KiB

Open AccessFeature PaperArticle

Understanding Slovakian Gas Well Performance and Capability through ArcGIS System Mapping

by Gabriel Wittenberger, Jozef Cambal, Erika Skvarekova, Andrea Senova and Ingrid Kanuchova

Processes 2021, 9(10), 1850; https://doi.org/10.3390/pr9101850 - 18 Oct 2021

Cited by 5 | Viewed by 3569

Abstract

There are two important territories in Slovakia with functioning gas well operations: the Eastern Slovak Lowland and the Vienna Basin. This article focuses on the creation of electronic monitoring and graphical mapping of the current technical conditions of gas wells in the Eastern [...] Read more.

There are two important territories in Slovakia with functioning gas well operations: the Eastern Slovak Lowland and the Vienna Basin. This article focuses on the creation of electronic monitoring and graphical mapping of the current technical conditions of gas wells in the Eastern Slovak Lowland. An analysis of the gas wells’ current state in the terrain is available. The aim of the article is to draw attention to the current state of gas wells, such as the insufficient processing of gas wells, the lack of summary and uniform records concerning them, and the lack of an electronic system for monitoring the technical security of the wells. The scientific contribution of this article lies in its ability to interpret and address operational problems related to gas wells. Through analogy, the step algorithm expresses the possibility of also using gas wells for oil, geothermal and hydrogeological wells. The intention was to highlight the importance of the need to create a database for the security and strategic needs of the state regarding the storage of natural gas. As of yet, no computer or graphic system has been used in Slovakia to monitor, unify and clarify the actual technical condition of gas wells. Using the ArcGIS electronic and graphical software tool, the mapping and recording of gas wells was carried out in the area under investigation. The mapping was completed with the mentioned technical patterns. These patterns have the information found on individual gas wells. After the information is added to the database, this mapping can also be carried out in another important area with functioning gas wells, such as in the Vienna Basin, which could be another theme for further research in this area. Full article

(This article belongs to the Special Issue Sustainable Development Processes for Renewable Energy Technology)

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15 pages, 825 KiB

Open AccessArticle

Voltage Stability Index Using New Single-Port Equivalent Based on Component Peculiarity and Sensitivity Persistence

by Muhammad Shoaib Bhutta, Muddassar Sarfraz, Larisa Ivascu, Hui Li, Ghulam Rasool, Zain ul Abidin Jaffri, Umer Farooq, Jamshed Ali Shaikh and Muhammad Shahzad Nazir

Processes 2021, 9(10), 1849; https://doi.org/10.3390/pr9101849 - 18 Oct 2021

Cited by 11 | Viewed by 2129

Abstract

A voltage stability index is proposed using a new single-port equivalent depending on component peculiarity representation and sensitivity persistence to locate and determine long-term voltage instability in transmission and distribution power networks. The suggested single-port equivalent effectively represents the equivalence of various component [...] Read more.

A voltage stability index is proposed using a new single-port equivalent depending on component peculiarity representation and sensitivity persistence to locate and determine long-term voltage instability in transmission and distribution power networks. The suggested single-port equivalent effectively represents the equivalence of various component types and assures the consistency of sensitivity information before and after the equivalence which is compulsory for the equivalent accuracy in estimating the voltage stability analysis. The stability index is derived from the new single-port equivalent to determine the system voltage instability. The proposed stability index is compared with indices based on virtual impedance and Thevenin impedance models. This new stability index shows more accuracy and effectiveness as compared to the indices based on virtual and Thevenin equivalent models. The index also determines the weak buses, where an improvement or functional measure can be used to reduce the system voltage instability. The validity of the proposed equivalent approach and stability index is presented by utilizing two radial systems, four IEEE systems and an actual system having bus size from five to 1010 buses. Full article

(This article belongs to the Special Issue Clean Energy Conversion Processes)

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19 pages, 6214 KiB

Open AccessFeature PaperArticle

Real-Time Parameter Identification for Forging Machine Using Reinforcement Learning

by Dapeng Zhang, Lifeng Du and Zhiwei Gao

Processes 2021, 9(10), 1848; https://doi.org/10.3390/pr9101848 - 18 Oct 2021

Cited by 4 | Viewed by 2241

Abstract

It is a challenge to identify the parameters of a mechanism model under real-time operating conditions disrupted by uncertain disturbances due to the deviation between the design requirement and the operational environment. In this paper, a novel approach based on reinforcement learning is [...] Read more.

It is a challenge to identify the parameters of a mechanism model under real-time operating conditions disrupted by uncertain disturbances due to the deviation between the design requirement and the operational environment. In this paper, a novel approach based on reinforcement learning is proposed for forging machines to achieve the optimal model parameters by applying the raw data directly instead of observation window. This approach is an online parameter identification algorithm in one period without the need of the labelled samples as training database. It has an excellent ability against unknown distributed disturbances in a dynamic process, especially capable of adapting to a new process without historical data. The effectiveness of the algorithm is demonstrated and validated by a simulation of acquiring the parameter values of a forging machine. Full article

(This article belongs to the Special Issue Modelling, Monitoring, Control and Optimization for Complex Industrial Processes)

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11 pages, 8800 KiB

Open AccessArticle

DEM–FEM Coupling Simulation of the Transfer Chute Wear with the Dynamic Calibration DEM Parameters

by Fangping Ye, Yuezhang Qiang, Weijie Jiang and Xiang Fu

Processes 2021, 9(10), 1847; https://doi.org/10.3390/pr9101847 - 18 Oct 2021

Cited by 2 | Viewed by 2610

Abstract

Transfer chutes for bulk material conveying systems have significant importance in ship loading and unloading and are ‘worn’ from large mass flow and fast granular material flow conditions. In this investigation, the impact forces of different granular materials on the transfer chute wear [...] Read more.

Transfer chutes for bulk material conveying systems have significant importance in ship loading and unloading and are ‘worn’ from large mass flow and fast granular material flow conditions. In this investigation, the impact forces of different granular materials on the transfer chute wear process are considered; the DEM–FEM (Discrete Element Method–Finite Element Method) coupling method was used to calculate the wear and the deformation of the transfer chute. The stress–strain and cumulative contact energy from three different granular materials were analyzed under different working conditions. The results show that the wear, stress–strain, and cumulative contact energy of the transfer chute are closely related to the belt speed, the chute inclination angle, and the types of granular materials; the impact force and the stress–strain on the transfer chute achieves maximum value under a 4 m/s belt speed condition; meanwhile, with the increase of belt speed by 0.5 m/s, the wear of the transfer chute increases 25% and the deformation increases 20%; the shape variable, wear area, and normal cumulative contact capacity of the transfer chute are the smallest with a transfer chute inclination angle from 40° to 45°. Full article

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

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18 pages, 2924 KiB

Open AccessFeature PaperArticle

Alkali and Alkali-Earth Metals Incorporation to Ni/USY Catalysts for CO₂ Methanation: The Effect of the Metal Nature

by M. Carmen Bacariza, Cláudia Grilo, Paula Teixeira, José M. Lopes and Carlos Henriques

Processes 2021, 9(10), 1846; https://doi.org/10.3390/pr9101846 - 18 Oct 2021

Cited by 3 | Viewed by 2304

Abstract

CO₂ methanation is typically carried out using Ni-supported catalysts containing promoters such as alkali or alkali-earth metals to improve their properties. In this work, bimetallic Ni-based USY zeolite catalysts containing alkali (Li, K and Cs) and alkali-earth (Mg, Ca) metal compounds were [...] Read more.

CO₂ methanation is typically carried out using Ni-supported catalysts containing promoters such as alkali or alkali-earth metals to improve their properties. In this work, bimetallic Ni-based USY zeolite catalysts containing alkali (Li, K and Cs) and alkali-earth (Mg, Ca) metal compounds were prepared using the same conditions (15 wt% of metals; co-impregnation), characterized by N₂ sorption, XRD, TGA, CO₂ adsorption–desorption, DRS UV-Vis and H₂-TPR, and finally applied in CO₂ methanation reaction (86,100 mL h⁻¹ g⁻¹, P_CO₂ = 0.16 bar, H₂:CO₂ = 4:1). For each group, the effects of the second metal nature on the properties and performances were assessed. Alkali metals incorporation induced considerably low catalytic performances (CH₄ yields < 26%), attributed to their negative impact on zeolite structure preservation. On the contrary, alkali-earth metal-containing catalysts exhibited lower structural damage. However, the formation of Ni-Mg mixed oxides in Ni-Mg/USY catalyst and CaCO₃ during the reaction in Ni-Ca/USY sample could explain their performances, similar or lower than those obtained for Ni/USY catalyst. Among the studied metals, calcium was identified as the most interesting (CH₄ yield of 65% at 415 °C), which was ascribed to the slight improvement of the Ni⁰ dispersion. Full article

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

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11 pages, 1119 KiB

Open AccessFeature PaperArticle

An Efficient Method of Calculating the Force and Torque in the Upsetting of Cylinders with Rotating Dies

by Sergei Alexandrov, Elena Lyamina and Yeong-Maw Hwang

Processes 2021, 9(10), 1845; https://doi.org/10.3390/pr9101845 - 18 Oct 2021

Viewed by 1949

Abstract

The process of upsetting, with rotating dies, is used to reduce the force required to deform the workpiece and to receive more homogeneous deformation compared to the same process without the rotational motion of the dies. The upper bound method is an efficient [...] Read more.

The process of upsetting, with rotating dies, is used to reduce the force required to deform the workpiece and to receive more homogeneous deformation compared to the same process without the rotational motion of the dies. The upper bound method is an efficient tool for a quick estimate of process parameters. The accuracy of upper bound solutions depends on the chosen class of kinematically admissible velocity fields. The present paper provides an efficient method for choosing kinematically admissible velocity fields that satisfy some stress boundary conditions if the associated flow rule is considered. The method applies to the upsetting of cylinders. It is expected that it leads to accurate solutions if friction is high enough. Besides, the kinematically admissible velocity field accounts for a rigid region near the axis of symmetry. Such a region inevitably occurs in exact solutions because the friction stress must vanish at the axis of symmetry. The final expression for the upper bound, on a combination of the force and torque, involves two arbitrary parameters. These parameters are determined using the upper bound theorem. An example is provided to illustrate the method. Full article

(This article belongs to the Special Issue Advances in Innovative Engineering Materials and Processes (II))

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15 pages, 545 KiB

Open AccessFeature PaperReview

Gaseous Emissions from the Composting Process: Controlling Parameters and Strategies of Mitigation

by Tahseen Sayara and Antoni Sánchez

Processes 2021, 9(10), 1844; https://doi.org/10.3390/pr9101844 - 18 Oct 2021

Cited by 37 | Viewed by 8646

Abstract

Organic waste generation, collection, and management have become a crucial problem in modern and developing societies. Among the technologies proposed in a circular economy and sustainability framework, composting has reached a strong relevance in terms of clean technology that permits reintroducing organic matter [...] Read more.

Organic waste generation, collection, and management have become a crucial problem in modern and developing societies. Among the technologies proposed in a circular economy and sustainability framework, composting has reached a strong relevance in terms of clean technology that permits reintroducing organic matter to the systems. However, composting has also negative environmental impacts, some of them of social concern. This is the case of composting atmospheric emissions, especially in the case of greenhouse gases (GHG) and certain families of volatile organic compounds (VOC). They should be taken into account in any environmental assessment of composting as organic waste management technology. This review presents the relationship between composting operation and composting gaseous emissions, in addition to typical emission values for the main organic wastes that are being composted. Some novel mitigation technologies to reduce gaseous emissions from composting are also presented (use of biochar), although it is evident that a unique solution does not exist, given the variability of exhaust gases from composting. Full article

(This article belongs to the Special Issue Composting in the Framework of Circular Economy)

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21 pages, 1696 KiB

Open AccessFeature PaperReview

Distribution of Sulfate-Reducing Bacteria in the Environment: Cryopreservation Techniques and Their Potential Storage Application

by Ivan Kushkevych, Aneta Kovářová, Dani Dordevic, Jonah Gaine, Peter Kollar, Monika Vítězová and Simon K.-M. R. Rittmann

Processes 2021, 9(10), 1843; https://doi.org/10.3390/pr9101843 - 18 Oct 2021

Cited by 12 | Viewed by 6315

Abstract

Sulfate-reducing bacteria (SRB) are a heterogeneous group of anaerobic microorganisms that play an important role in producing hydrogen sulfide not only in the natural environment, but also in the gastrointestinal tract and oral cavity of animals and humans. The present review was written [...] Read more.

Sulfate-reducing bacteria (SRB) are a heterogeneous group of anaerobic microorganisms that play an important role in producing hydrogen sulfide not only in the natural environment, but also in the gastrointestinal tract and oral cavity of animals and humans. The present review was written with the inclusion of 110 references including the time period from 1951 to 2021. The following databases were evaluated: Web of Science, Scopus and Google Scholar. The articles chosen to be included in the review were written mainly in the English and Czech languages. The molecular mechanisms of microbial cryoprotection differ depending on the environment where microorganisms were initially isolated. It was observed that the viability of microorganisms after cryopreservation is dependent on a number of factors, primarily colony age, amount of inoculum, cell size or rate of cooling, and their molecular inventory. Therefore, this paper is devoted to assessing the performance and suitability of various cryopreservation methods of intestinal bacteria, including molecular mechanisms of their protection. In order to successfully complete the cryopreservation process, selecting the correct laboratory equipment and cryopreservation methodology is important. Our analysis revealed that SRB should be stored in glass vials to help mitigate the corrosive nature of hydrogen sulfide, which can affect their physiology on a molecular level. Furthermore, it is recommended that their storage be performed in distilled water or in a suspension with a low salt concentration. From a molecular biological and bioengineering perspective, this contribution emphasizes the need to consider the potential impact associated with SRB in the medical, construction, and environmental sectors. Full article

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

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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 4110

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, 3911 KiB

Open AccessCommunication

Introducing a Marine Biorefinery System for the Integrated Production of Biofuels, High-Value-Chemicals, and Co-Products: A Path Forward to a Sustainable Future

by Abdelrahman Saleh Zaky

Processes 2021, 9(10), 1841; https://doi.org/10.3390/pr9101841 - 17 Oct 2021

Cited by 17 | Viewed by 4999

Abstract

Biofuels have many environmental and practical benefits as a transportation fuel. They are among the best alternatives to fossil fuels- thanks to their capacity for negative carbon emissions, which is vital for archiving the global ambition of a net-zero economy. However, conventional biofuel [...] Read more.

Biofuels have many environmental and practical benefits as a transportation fuel. They are among the best alternatives to fossil fuels- thanks to their capacity for negative carbon emissions, which is vital for archiving the global ambition of a net-zero economy. However, conventional biofuel production takes place on inland sites and relies on freshwater and edible crops (or land suitable for edible crop production), which has led to the food versus fuel debate. It also suffers technical and economical barriers owing to the energy balance and the cost of production compared with fossil fuels. Establishing a coastal integrated marine biorefinery (CIMB) system for the simultaneous production of biofuels, high-value chemicals, and other co-products could be the ultimate solution. The proposed system is based on coastal sites and relies entirely on marine resources including seawater, marine biomass (seaweed), and marine microorganisms (marine yeasts and marine microalgae). The system does not require the use of arable land and freshwater in any part of the production chain and should be linked to offshore renewable energy sources to increase its economic feasibility and environmental value. This article aims to introduce the CIMB system as a potential vehicle for addressing the global warming issue and speeding the global effort on climate change mitigation as well as supporting the world’s water, food and energy security. I hope these perspectives serve to draw attention into research funding for this approach. Full article

(This article belongs to the Special Issue Bioethanol Production Processes)

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18 pages, 1085 KiB

Open AccessFeature PaperArticle

Polyphenolic Characterization and Antioxidant Capacity of Laurus nobilis L. Leaf Extracts Obtained by Green and Conventional Extraction Techniques

by Erika Dobroslavić, Ivona Elez Garofulić, Zoran Zorić, Sandra Pedisić and Verica Dragović-Uzelac

Processes 2021, 9(10), 1840; https://doi.org/10.3390/pr9101840 - 16 Oct 2021

Cited by 30 | Viewed by 3736

Abstract

Laurus nobilis L. is an evergreen Mediterranean shrub whose leaves have been known for various health-promoting effects mainly attributed to polyphenols. Microwave- (MAE) and ultrasound-assisted extraction (UAE) are green extraction techniques that enable effective isolation of polyphenols from plant material. Therefore, the aim [...] Read more.

Laurus nobilis L. is an evergreen Mediterranean shrub whose leaves have been known for various health-promoting effects mainly attributed to polyphenols. Microwave- (MAE) and ultrasound-assisted extraction (UAE) are green extraction techniques that enable effective isolation of polyphenols from plant material. Therefore, the aim of this research was to optimize the extraction conditions of MAE (ethanol percentage, temperature, extraction time, microwave power) and UAE (ethanol percentage, extraction time, amplitude) of polyphenols from Laurus nobilis L. leaves and to assess their polyphenolic profile by ultra performance liquid chromatography- tandem mass spectrometry (UPLC-MS/MS) and antioxidant capacity by oxygen radical absorbance capacity (ORAC) assay. Optimal MAE conditions were 50% ethanol, 80 °C, 10 min and 400 W. Optimal UAE conditions were 70% ethanol, 10 min and 50% amplitude. Spectrophotometric analysis showed the highest total phenolic content in the extracts was obtained by MAE, compared to conventional heat-reflux extraction (CRE) and UAE. The polyphenolic profile of all obtained extracts included 29 compounds, with kaempferol and quercetin glycosides being the most abundant. UPLC-MS/MS showed the highest total phenolic content in the extracts obtained by CRE. ORAC assay showed the highest antioxidant capacity in extracts obtained by CRE, which is in agreement with the polyphenolic profile determined by UPLC-MS/MS. Full article

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

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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 23230

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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20 pages, 4271 KiB

Open AccessFeature PaperArticle

Evaluation of Practical Applicability and Synergistic Effects of Bio-Based Food Packaging Materials Combined with Plant-Based Stabilisers

by Thomas Havelt, Sarah Brettschneider and Michaela Schmitz

Processes 2021, 9(10), 1838; https://doi.org/10.3390/pr9101838 - 15 Oct 2021

Cited by 7 | Viewed by 2525

Abstract

Different analyses and feasibility studies have been conducted on the plant extracts of thyme (Thymus vulgaris), European horse chestnut (Aesculus hippocastanum), Nordmann fir (Abies nordmanniana), and snowdrop (Galanthus elwesii) to evaluate bio-based alternatives to common [...] Read more.

Different analyses and feasibility studies have been conducted on the plant extracts of thyme (Thymus vulgaris), European horse chestnut (Aesculus hippocastanum), Nordmann fir (Abies nordmanniana), and snowdrop (Galanthus elwesii) to evaluate bio-based alternatives to common petrol-based stabilisers. For this purpose, in this study, plant extracts were incorporated into poly-lactic acid films (PLA) at different concentrations. The films’ UV absorbance and migration into packed food was analysed via photometric assays (ABTS radical cation scavenging capacity assay, β-carotene assay) and GC–MS analysis. Furthermore, the synergistic antioxidant effects of various combinations of extracts and isolated active compounds were determined. This way, antioxidant effects can be increased, allowing for a highly effective use of resources. All extracts were successfully incorporated into PLA films and showed notable photoabsorbing effects, while no migration risk was observed. Depending on extract combinations, high synergistic effects of up to 726% can be utilised to improve the effectiveness of bio-based extracts. This applies particularly to tomato paste and Aesculus hippocastanum extracts, which overall show high synergistic and antioxidant effects in combination with each other and with isolated active compounds. The study shows that it is possible to create safe bio-based antioxidant films which show even improved properties when using highlighted target combinations. Full article

(This article belongs to the Special Issue Significance and Applicability of Bioactive Compounds from Plants for Innovative Technologies and Processes)

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9 pages, 3692 KiB

Open AccessFeature PaperArticle

Influence of Microwave Frequency and Gas Humidity on the In-Vitro Blood Coagulation in Cold Atmospheric Pressure Plasma

by Jie Yu, Li Wu and Kama Huang

Processes 2021, 9(10), 1837; https://doi.org/10.3390/pr9101837 - 15 Oct 2021

Cited by 1 | Viewed by 1916

Abstract

In this article, the effects of microwave frequency (2450 MHz and 5800 MHz) and gas humidity (1%, 2%, 3%, 4%, 6% and 8%) on in vitro blood coagulation with cold atmospheric pressure plasma (CAPP) were investigated. The generation of reactive oxygen species (ROS, [...] Read more.

In this article, the effects of microwave frequency (2450 MHz and 5800 MHz) and gas humidity (1%, 2%, 3%, 4%, 6% and 8%) on in vitro blood coagulation with cold atmospheric pressure plasma (CAPP) were investigated. The generation of reactive oxygen species (ROS, OH, O) was measured by optical emission spectra. The exposure temperature on blood droplets under treatment was below 55 °C in all cases, to avoid the thermal effect of plasma on the blood clotting. Investigations showed that, with the increase of frequency, the doses of ROS increased, the blood sample presented a more serious collapse and its surface became drier. The humidity of ionized gas can also accelerate the generation of ROS and the process of blood clotting. Our results propose a method to accelerate in vitro blood coagulation in CAPP by adjusting microwave frequency and gas humidity, and suggest a clinical benefit for plasma treatment as a coagulation device in surgery. Full article

(This article belongs to the Section Materials Processes)

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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 3370

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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12 pages, 2125 KiB

Open AccessFeature PaperArticle

Wet Torrefaction of Poultry Litter in a Pilot Unit: A Numerical Assessment of the Process Parameters

by Rafail Isemin, Frederic Marias, Natalia Muratova, Sergey Kuzmin, Dmitry Klimov, Alexander Mikhalev, Oleg Milovanov, Mathieu Brulé and Fouzi Tabet

Processes 2021, 9(10), 1835; https://doi.org/10.3390/pr9101835 - 15 Oct 2021

Cited by 8 | Viewed by 2024

Abstract

A numerical model for the wet torrefaction of poultry litter in a pilot unit was developed in this study. The model accounted for the following process steps: preheating biomass in a feed hopper, feeding biomass into the reactor, fluidized-bed generation using superheated steam, [...] Read more.

A numerical model for the wet torrefaction of poultry litter in a pilot unit was developed in this study. The model accounted for the following process steps: preheating biomass in a feed hopper, feeding biomass into the reactor, fluidized-bed generation using superheated steam, and the supply of additional heat by the electric heating of the reactor walls. Following a “black box” approach, a major assumption of the model is that the behavior of the fluidized-bed reactor is similar to a completely stirred tank reactor (CSTR). Under this assumption, the properties of the particles and gases do not depend on their location inside the reactor. During wet torrefaction, poultry-litter biomass was heated to a predetermined temperature and decomposed, generating biochar along with a gas phase (torgas), whose amounts depended on the content of inert ash in the biomass particles. Variable optimization in the model was performed using MATLAB software. The model successfully estimated the optimal duration required for the completion of wet torrefaction under various conditions: temperature, batch weight, reactor dimensions, etc. The model was validated using experimental data obtained from a series of wet torrefaction experiments performed in a fluidized bed, and provided reliable estimations of the duration of the process depending on material properties, reactor size and feedstock characteristics. Full article

(This article belongs to the Special Issue Trends and Prospects of Biofuels: Literature, Experimental, and Techno-Economic Analysis)

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13 pages, 2168 KiB

Open AccessFeature PaperArticle

Production of Omega-3 Oil by Aurantiochytrium mangrovei Using Spent Osmotic Solution from Candied Fruit Industry as Sole Organic Carbon Source

by Giovanni L. Russo, Antonio L. Langellotti, Thierry Blasco, Maria Oliviero, Raffaele Sacchi and Paolo Masi

Processes 2021, 9(10), 1834; https://doi.org/10.3390/pr9101834 - 15 Oct 2021

Cited by 15 | Viewed by 2673

Abstract

Osmotic dehydration is an important phase in the production of dried products, including most fruits and vegetables, in the food industry. The drying process for candied fruit produces a liquid waste called “spent osmotic solution”, which is characterized by a high content of [...] Read more.

Osmotic dehydration is an important phase in the production of dried products, including most fruits and vegetables, in the food industry. The drying process for candied fruit produces a liquid waste called “spent osmotic solution”, which is characterized by a high content of organic compounds, mostly dissolved sugars. The sugar content of this food by-product could be valorized through the growth of biomass with a high added value. In this study, the spent osmotic solution from the candied fruit industry was used as an organic carbon source for the growth and production of docosahexaenoic acid (DHA) in the cultivation of Aurantiochytrium mangrovei RCC893. The carbon content of the standard media was completely replaced by the sugars present in this food by-product. After that, the growth condition of this strain was optimized through response surface methodologies using a central composite design (CCD), and the optimal combination of the spent osmotic solution and nitrogen was established. Moreover, a scale-up trial was performed using the optimal conditions obtained after CCD to evaluate the scalability of the process. Full article

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

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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 4008

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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16 pages, 75073 KiB

Open AccessArticle

Research of Flow Stability of Non-Newtonian Magnetorheological Fluid Flow in the Gap between Two Cylinders

by Milada Kozubková, Jana Jablonská, Marian Bojko, František Pochylý and Simona Fialová

Processes 2021, 9(10), 1832; https://doi.org/10.3390/pr9101832 - 15 Oct 2021

Viewed by 2135

Abstract

This paper deals with a mathematical modeling of flow stability of Newtonian and non-Newtonian fluids in the gap between two concentric cylinders, one of which rotates. A typical feature of the flow is the formation of a vortex flow, so-called Taylor vortices. Vortex [...] Read more.

This paper deals with a mathematical modeling of flow stability of Newtonian and non-Newtonian fluids in the gap between two concentric cylinders, one of which rotates. A typical feature of the flow is the formation of a vortex flow, so-called Taylor vortices. Vortex structures are affected by the speed of the rotating cylinder and the physical properties of the fluids, i.e., viscosity and density. Analogy in terms of viscosity is assumed for non-Newtonian and magnetorheological fluids. Mathematical models of laminar, transient and turbulent flow with constant viscosity and viscosity as a function of the deformation gradient were formulated and numerically solved to analyze the stability of single-phase flow. To verify them, a physical experiment was performed for Newtonian fluids using visualizations of vortex structures—Taylor vortices. Based on the agreement of selected numerical and physical results, the experience was used for numerical simulations of non-Newtonian magnetorheological fluid flow. Full article

(This article belongs to the Special Issue Experimental and Numerical Methods in Fluid Mechanics and Energy)

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33 pages, 7016 KiB

Open AccessReview

Electrocoagulation Process: An Approach to Continuous Processes, Reactors Design, Pharmaceuticals Removal, and Hybrid Systems—A Review

by Miriam López-Guzmán, Manuel Alberto Flores-Hidalgo and Liliana Reynoso-Cuevas

Processes 2021, 9(10), 1831; https://doi.org/10.3390/pr9101831 - 15 Oct 2021

Cited by 22 | Viewed by 9874

Abstract

The electrocoagulation (EC) process has been widely studied in recent years to remove a wide range of contaminants present in different types of water: fluorides, arsenic, heavy metals, organic matter, colorants, oils, and recently, pharmaceutical compounds. However, most of the studies have been [...] Read more.

The electrocoagulation (EC) process has been widely studied in recent years to remove a wide range of contaminants present in different types of water: fluorides, arsenic, heavy metals, organic matter, colorants, oils, and recently, pharmaceutical compounds. However, most of the studies have been aimed at understanding the process factors that have the most significant effect on efficiency, and these studies have been mainly on a batch process. Therefore, this review is focused on elucidating the current state of development of this process and the challenges it involves transferring to continuous processes and the recent exploration of its potential use in the removal of pharmaceutical contaminants and its implementation with other technologies. Full article

(This article belongs to the Special Issue Pollutant Removal and Separation Processes in Chemical Engineering)

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10 pages, 3305 KiB

Open AccessFeature PaperArticle

SBMLWebApp: Web-Based Simulation, Steady-State Analysis, and Parameter Estimation of Systems Biology Models

by Takahiro G. Yamada, Kaito Ii, Matthias König, Martina Feierabend, Andreas Dräger and Akira Funahashi

Processes 2021, 9(10), 1830; https://doi.org/10.3390/pr9101830 - 15 Oct 2021

Viewed by 4321

Abstract

In systems biology, biological phenomena are often modeled by Ordinary Differential Equations (ODEs) and distributed in the de facto standard file format SBML. The primary analyses performed with such models are dynamic simulation, steady-state analysis, and parameter estimation. These methodologies are mathematically formalized, [...] Read more.

In systems biology, biological phenomena are often modeled by Ordinary Differential Equations (ODEs) and distributed in the de facto standard file format SBML. The primary analyses performed with such models are dynamic simulation, steady-state analysis, and parameter estimation. These methodologies are mathematically formalized, and libraries for such analyses have been published. Several tools exist to create, simulate, or visualize models encoded in SBML. However, setting up and establishing analysis environments is a crucial hurdle for non-modelers. Therefore, easy access to perform fundamental analyses of ODE models is a significant challenge. We developed SBMLWebApp, a web-based service to execute SBML-based simulation, steady-state analysis, and parameter estimation directly in the browser without the need for any setup or prior knowledge to address this issue. SBMLWebApp visualizes the result and numerical table of each analysis and provides a download of the results. SBMLWebApp allows users to select and analyze SBML models directly from the BioModels Database. Taken together, SBMLWebApp provides barrier-free access to an SBML analysis environment for simulation, steady-state analysis, and parameter estimation for SBML models. SBMLWebApp is implemented in Java™ based on an Apache Tomcat^® web server using COPASI, the Systems Biology Simulation Core Library (SBSCL), and LibSBMLSim as simulation engines. SBMLWebApp is licensed under MIT with source code freely available. At the end of this article, the Data Availability Statement gives the internet links to the two websites to find the source code and run the program online. Full article

(This article belongs to the Special Issue Next-Generation Methods and Simulation Tools for Systems Biology)

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12 pages, 2112 KiB

Open AccessArticle

Single and Binary Adsorption Behaviour and Mechanisms of Cd²⁺, Cu²⁺ and Ni²⁺ onto Modified Biochar in Aqueous Solutions

by Liwen Zheng, Yongchao Gao, Jianhua Du, Wen Zhang, Yujie Huang, Qingqing Zhao, Luchun Duan, Yanju Liu, Ravi Naidu and Xiangliang Pan

Processes 2021, 9(10), 1829; https://doi.org/10.3390/pr9101829 - 14 Oct 2021

Cited by 22 | Viewed by 2639

Abstract

The chitosan–EDTA modified magnetic biochar (E–CMBC) was successfully used as a novel adsorbent to remove heavy metals. The adsorption behaviour and mechanisms of E–CMBC to Cd²⁺, Cu²⁺ and Ni²⁺ were performed in single and binary system in aqueous solutions. [...] Read more.

The chitosan–EDTA modified magnetic biochar (E–CMBC) was successfully used as a novel adsorbent to remove heavy metals. The adsorption behaviour and mechanisms of E–CMBC to Cd²⁺, Cu²⁺ and Ni²⁺ were performed in single and binary system in aqueous solutions. In single–metal system, the adsorption process of Cd²⁺, Cu²⁺ and Ni²⁺ on E–CMBC fitted well with the Avrami fractional–order kinetics model and the Langmuir isotherm model. The measured maximum adsorption capacities were 61.08 mg g⁻¹, 48.36 mg g⁻¹ and 41.17 mg g⁻¹ for Cd²⁺, Cu²⁺ and Ni²⁺, respectively. In binary–metal system, coexisting ions have obvious competitive adsorption behaviour on E–CMBC when the concentration of heavy meal beyond 20 mg L⁻¹. The maximum adsorption capacities of the heavy metals were found to be lower than that in single–metal system. The order of the competitive adsorption ability was Cu²⁺ > Ni²⁺ > Cd²⁺. Interestingly, in Cd²⁺–Cu²⁺ system the earlier adsorbed Cd²⁺ could be completely replaced by Cu²⁺ from the solution. Different competitive adsorption ability of those heavy metal were due to the characteristics of heavy metal and resultant affinity of the adsorption sites on E–CMBC. The adsorption mechanism indicated that chemical adsorption played a dominating role. Therefore, E–CMBC could be a potential adsorbent for wastewater treatment. Full article

(This article belongs to the Section Materials Processes)

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