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Volume 11
Issue 4
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Appl. Sci., Volume 11, Issue 4 (February-2 2021) – 621 articles

Cover Story (view full-size image): Polymeric bioresorbable stents (BRS) are designed to mitigate the side effects of traditional inert metallic stents, such as chronic inflammation and late thrombosis, but are not bioactive. To improve their biointegration, it is crucial that stents undergo autologous luminal endothelialization. Moreover, the current fabrication techniques of stents, extrusion of tubes and laser cutting, do not allow performing customizable stents addressed to patients with special needs. This article investigates the effect of different functionalization strategies onto solvent-cast poly(L-lactic acid) surfaces with the capacity to accelerate the surface endothelialization and the fabrication of 3D-printed BRS via the solvent-cast direct writing technique. View this paper
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20 pages, 29791 KiB  
Review
Phosphogypsum Recycling: A Review of Environmental Issues, Current Trends, and Prospects
by Yelizaveta Chernysh, Olena Yakhnenko, Viktoriia Chubur and Hynek Roubík
Appl. Sci. 2021, 11(4), 1575; https://doi.org/10.3390/app11041575 - 9 Feb 2021
Cited by 267 | Viewed by 18989
Abstract
The problem of recycling and storage of phosphogypsum is topical for many countries around the world, as it is associated with environmental problems of pollution of water bodies, land, and atmosphere. Therefore, this paper analyzes the directions of phosphogypsum recycling and possible alternatives [...] Read more.
The problem of recycling and storage of phosphogypsum is topical for many countries around the world, as it is associated with environmental problems of pollution of water bodies, land, and atmosphere. Therefore, this paper analyzes the directions of phosphogypsum recycling and possible alternatives to its use. The main disadvantages of the existing methods of phosphogypsum processing were identified and trends in this waste management were also considered. Through the VOSviewer programme, a visualization of cluster interconnections was carried out in research publications of various fields of phosphogypsum utilization. Five clusters were formed: a red cluster—phosphogypsum recycling in the construction industry; green cluster—radiation pollution problem of phosphogypsum and phosphate fertilizers; yellow cluster—monitoring migration of phosphogypsum components in the ecosystem, with the mobile forms of heavy metals and their inflow into aquifers from phosphogypsum dumps; blue cluster—use of phosphogypsum in agriculture as an ameliorant and a component of fertilizer; and a purple cluster—the impact of phosphogypsum on microorganisms, particularly in bioremediation processes. Under the proposed integrated biochemical approach, the use of various bioprocesses of phosphogypsum recovery from waste dumps and implementation of new biotechnological solutions for processing phosphorus raw materials are presented. Full article
(This article belongs to the Section Environmental Sciences)
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14 pages, 5613 KiB  
Article
Hybrid Metal/Polymer Filaments for Fused Filament Fabrication (FFF) to Print Metal Parts
by Claudio Tosto, Jacopo Tirillò, Fabrizio Sarasini and Gianluca Cicala
Appl. Sci. 2021, 11(4), 1444; https://doi.org/10.3390/app11041444 - 5 Feb 2021
Cited by 109 | Viewed by 7777
Abstract
The exploitation of mechanical properties and customization possibilities of 3D printed metal parts usually come at the cost of complex and expensive equipment. To address this issue, hybrid metal/polymer composite filaments have been studied allowing the printing of metal parts by using the [...] Read more.
The exploitation of mechanical properties and customization possibilities of 3D printed metal parts usually come at the cost of complex and expensive equipment. To address this issue, hybrid metal/polymer composite filaments have been studied allowing the printing of metal parts by using the standard Fused Filament Fabrication (FFF) approach. The resulting hybrid metal/polymer part, the so called “green”, can then be transformed into a dense metal part using debinding and sintering cycles. In this work, we investigated the manufacturing and characterization of green and sintered parts obtained by FFF of two commercial hybrid metal/polymer filaments, i.e., the Ultrafuse 316L by BASF and the 17-4 PH by Markforged. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS) analyses of the mesostructure highlighted incomplete raster bonding and voids like those observed in conventional FFF-printed polymeric structures despite the sintering cycle. A significant role in the tensile properties was played by the building orientation, with samples printed flatwise featuring the highest mechanical properties, though lower than those achievable with standard metal additive manufacturing techniques. Full article
(This article belongs to the Special Issue Design, Synthesis and Characterization of Hybrid Composite Materials)
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24 pages, 4684 KiB  
Review
Arsenic Contamination of Groundwater and Its Implications for Drinking Water Quality and Human Health in Under-Developed Countries and Remote Communities—A Review
by Samuel B. Adeloju, Shahnoor Khan and Antonio F. Patti
Appl. Sci. 2021, 11(4), 1926; https://doi.org/10.3390/app11041926 - 22 Feb 2021
Cited by 107 | Viewed by 15237
Abstract
Arsenic is present naturally in many geological formations around the world and has been found to be a major source of contamination of groundwater in some countries. This form of contamination represents a serious threat to health, economic and social well-being, particularly in [...] Read more.
Arsenic is present naturally in many geological formations around the world and has been found to be a major source of contamination of groundwater in some countries. This form of contamination represents a serious threat to health, economic and social well-being, particularly in under-developed countries and remote communities. The chemistry of arsenic and the factors that influence the form(s) in which it may be present and its fate when introduced into the environment is discussed briefly in this review. A global overview of arsenic contamination of groundwater around the world is then discussed. As a case study, the identified and established causes of groundwater contamination by arsenic in Bangladesh is highlighted and a perspective is provided on the consequential health, agricultural, social and economic impacts. In addition, the relevant removal strategies that have been developed and can generally be used to remediate arsenic contamination are discussed. Also, the possible influence of groundwater inorganic compositions, particularly iron and phosphate, on the effectiveness of arsenic removal is discussed. Furthermore, some specific examples of the filter systems developed successfully for domestic arsenic removal from groundwater to provide required potable water for human consumption are discussed. Lastly, important considerations for further improving the performance and effectiveness of these filter systems for domestic use are outlined. Full article
(This article belongs to the Special Issue 10th Anniversary of Applied Sciences-Invited Papers in Chemistry Section)
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21 pages, 595 KiB  
Article
Intelligent Cyber Attack Detection and Classification for Network-Based Intrusion Detection Systems
by Nuno Oliveira, Isabel Praça, Eva Maia and Orlando Sousa
Appl. Sci. 2021, 11(4), 1674; https://doi.org/10.3390/app11041674 - 13 Feb 2021
Cited by 97 | Viewed by 10604
Abstract
With the latest advances in information and communication technologies, greater amounts of sensitive user and corporate information are shared continuously across the network, making it susceptible to an attack that can compromise data confidentiality, integrity, and availability. Intrusion Detection Systems (IDS) are important [...] Read more.
With the latest advances in information and communication technologies, greater amounts of sensitive user and corporate information are shared continuously across the network, making it susceptible to an attack that can compromise data confidentiality, integrity, and availability. Intrusion Detection Systems (IDS) are important security mechanisms that can perform the timely detection of malicious events through the inspection of network traffic or host-based logs. Many machine learning techniques have proven to be successful at conducting anomaly detection throughout the years, but only a few considered the sequential nature of data. This work proposes a sequential approach and evaluates the performance of a Random Forest (RF), a Multi-Layer Perceptron (MLP), and a Long-Short Term Memory (LSTM) on the CIDDS-001 dataset. The resulting performance measures of this particular approach are compared with the ones obtained from a more traditional one, which only considers individual flow information, in order to determine which methodology best suits the concerned scenario. The experimental outcomes suggest that anomaly detection can be better addressed from a sequential perspective. The LSTM is a highly reliable model for acquiring sequential patterns in network traffic data, achieving an accuracy of 99.94% and an f1-score of 91.66%. Full article
(This article belongs to the Special Issue Machine Learning for Cybersecurity Threats, Challenges, and Opportunities)
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20 pages, 9181 KiB  
Review
Schiff Bases: Interesting Scaffolds with Promising Antitumoral Properties
by Domenico Iacopetta, Jessica Ceramella, Alessia Catalano, Carmela Saturnino, Maria Grazia Bonomo, Carlo Franchini and Maria Stefania Sinicropi
Appl. Sci. 2021, 11(4), 1877; https://doi.org/10.3390/app11041877 - 20 Feb 2021
Cited by 86 | Viewed by 6574
Abstract
Schiff bases, named after Hugo Schiff, are highly reactive organic compounds broadly used as pigments and dyes, catalysts, intermediates in organic synthesis, and polymer stabilizers. Lots of Schiff bases are described in the literature for various biological activities, including antimalarial, antibacterial, antifungal, anti-inflammatory, [...] Read more.
Schiff bases, named after Hugo Schiff, are highly reactive organic compounds broadly used as pigments and dyes, catalysts, intermediates in organic synthesis, and polymer stabilizers. Lots of Schiff bases are described in the literature for various biological activities, including antimalarial, antibacterial, antifungal, anti-inflammatory, and antiviral. Schiff bases are also known for their ability to form complexes with several metals. Very often, complexes of Schiff bases with metals and Schiff bases alone have demonstrated interesting antitumor activity. Given the innumerable vastness of data regarding antitumor activity of all these compounds, we focused our attention on mono- and bis-Schiff bases alone as antitumor agents. We will highlight the most significant examples of compounds belonging to this class reported in the literature. Full article
(This article belongs to the Special Issue Anticancer Drugs Activity and Underlying Mechanisms)
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19 pages, 1423 KiB  
Review
Nanotechnology Development for Formulating Essential Oils in Wound Dressing Materials to Promote the Wound-Healing Process: A Review
by Ilenia De Luca, Parisa Pedram, Arash Moeini, Pierfrancesco Cerruti, Gianfranco Peluso, Anna Di Salle and Natalie Germann
Appl. Sci. 2021, 11(4), 1713; https://doi.org/10.3390/app11041713 - 14 Feb 2021
Cited by 79 | Viewed by 13404
Abstract
Wound healing refers to the replacement of damaged tissue through strongly coordinated cellular events. The patient’s condition and different types of wounds complicate the already intricate healing process. Conventional wound dressing materials seem to be insufficient to facilitate and support this mechanism. Nanotechnology [...] Read more.
Wound healing refers to the replacement of damaged tissue through strongly coordinated cellular events. The patient’s condition and different types of wounds complicate the already intricate healing process. Conventional wound dressing materials seem to be insufficient to facilitate and support this mechanism. Nanotechnology could provide the physicochemical properties and specific biological responses needed to promote the healing process. For nanoparticulate dressing design, growing interest has focused on natural biopolymers due to their biocompatibility and good adaptability to technological needs. Polysaccharides are the most common natural biopolymers used for wound-healing materials. In particular, alginate and chitosan polymers exhibit intrinsic antibacterial and anti-inflammatory effects, useful for guaranteeing efficient treatment. Recent studies highlight that several natural plant-derived molecules can influence healing stages. In particular, essential oils show excellent antibacterial, antifungal, antioxidant, and anti-inflammatory properties that can be amplified by combining them with nanotechnological strategies. This review summarizes recent studies concerning essential oils as active secondary compounds in polysaccharide-based wound dressings. Full article
(This article belongs to the Special Issue Nanotechnology in Tissue Engineering)
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21 pages, 60538 KiB  
Review
Flavor Chemistry of Virgin Olive Oil: An Overview
by Alessandro Genovese, Nicola Caporaso and Raffaele Sacchi
Appl. Sci. 2021, 11(4), 1639; https://doi.org/10.3390/app11041639 - 11 Feb 2021
Cited by 78 | Viewed by 13882
Abstract
Virgin olive oil (VOO) has unique chemical characteristics among all other vegetable oils which are of paramount importance for human health. VOO constituents are also responsible of its peculiar flavor, a complex sensation due to a combination of aroma, taste, texture, and mouthfeel [...] Read more.
Virgin olive oil (VOO) has unique chemical characteristics among all other vegetable oils which are of paramount importance for human health. VOO constituents are also responsible of its peculiar flavor, a complex sensation due to a combination of aroma, taste, texture, and mouthfeel or trigeminal sensations. VOO flavor depends primarily on the concentration and nature of volatile and phenolic compounds present in olive oil which can change dramatically depending on agronomical and technological factors. Another aspect that can change the flavor perception is linked to the oral process during olive oil tasting. In fact, in this case, some human physiological and matrix effects modulate the flavor release in the mouth. The present review aims to give an overview on VOO flavor, with particular emphasis on the mechanisms affecting its production and release during a tasting. Full article
(This article belongs to the Special Issue Advances in Food Flavor Analysis)
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39 pages, 5678 KiB  
Review
Melt Electrospinning of Polymers: Blends, Nanocomposites, Additives and Applications
by Anna Bachs-Herrera, Omid Yousefzade, Luis J. del Valle and Jordi Puiggali
Appl. Sci. 2021, 11(4), 1808; https://doi.org/10.3390/app11041808 - 18 Feb 2021
Cited by 77 | Viewed by 12936
Abstract
Melt electrospinning has been developed in the last decade as an eco-friendly and solvent-free process to fill the gap between the advantages of solution electrospinning and the need of a cost-effective technique for industrial applications. Although the benefits of using melt electrospinning compared [...] Read more.
Melt electrospinning has been developed in the last decade as an eco-friendly and solvent-free process to fill the gap between the advantages of solution electrospinning and the need of a cost-effective technique for industrial applications. Although the benefits of using melt electrospinning compared to solution electrospinning are impressive, there are still challenges that should be solved. These mainly concern to the improvement of polymer melt processability with reduction of polymer degradation and enhancement of fiber stability; and the achievement of a good control over the fiber size and especially for the production of large scale ultrafine fibers. This review is focused in the last research works discussing the different melt processing techniques, the most significant melt processing parameters, the incorporation of different additives (e.g., viscosity and conductivity modifiers), the development of polymer blends and nanocomposites, the new potential applications and the use of drug-loaded melt electrospun scaffolds for biomedical applications. Full article
(This article belongs to the Special Issue Biodegradable Scaffolds 2021)
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12 pages, 2724 KiB  
Article
Underwater Acoustic Target Recognition with a Residual Network and the Optimized Feature Extraction Method
by Feng Hong, Chengwei Liu, Lijuan Guo, Feng Chen and Haihong Feng
Appl. Sci. 2021, 11(4), 1442; https://doi.org/10.3390/app11041442 - 5 Feb 2021
Cited by 75 | Viewed by 5183
Abstract
Underwater Acoustic Target Recognition (UATR) remains one of the most challenging tasks in underwater signal processing due to the lack of labeled data acquisition, the impact of the time-space varying intrinsic characteristics, and the interference from other noise sources. Although some deep learning [...] Read more.
Underwater Acoustic Target Recognition (UATR) remains one of the most challenging tasks in underwater signal processing due to the lack of labeled data acquisition, the impact of the time-space varying intrinsic characteristics, and the interference from other noise sources. Although some deep learning methods have been proven to achieve state-of-the-art accuracy, the accuracy of the recognition task can be improved by designing a Residual Network and optimizing feature extraction. To give a more comprehensive representation of the underwater acoustic signal, we first propose the three-dimensional fusion features along with the data augment strategy of SpecAugment. Afterward, an 18-layer Residual Network (ResNet18), which contains the center loss function with the embedding layer, is designed to train the aggregated features with an adaptable learning rate. The recognition experiments are conducted on the ship-radiated noise dataset from a real environment, and the accuracy results of 94.3% indicate that the proposed method is appropriate for underwater acoustic recognition problems and sufficiently surpasses other classification methods. Full article
(This article belongs to the Section Acoustics and Vibrations)
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20 pages, 7987 KiB  
Article
Shake Table Testing of Standard Cold-Formed Steel Storage Rack
by Ahmad Firouzianhaji, Nima Usefi, Bijan Samali and Peyman Mehrabi
Appl. Sci. 2021, 11(4), 1821; https://doi.org/10.3390/app11041821 - 18 Feb 2021
Cited by 73 | Viewed by 3525
Abstract
Full-scale shake table investigations are strongly required to understand the actual performance of storage racks and to improve the rack design guidelines. This paper presents the results of full-scale shake table tests on New Zealand standard storage rack frames with two-bay and two-level [...] Read more.
Full-scale shake table investigations are strongly required to understand the actual performance of storage racks and to improve the rack design guidelines. This paper presents the results of full-scale shake table tests on New Zealand standard storage rack frames with two-bay and two-level to determine the dynamic characteristics of a standard rack structure and to measure the damping of the system. The experimental program was conducted in three phases. First, the identification parameters including the natural frequency and damping of the system were determined through a series of preliminary tests. Then, shake table tests were performed to capture the inelastic response of rack frames under low to medium intensities of El-Centro ground motion. Finally, the shake-table tests were repeated with scaling down the time domain and broader ranges of ground motion intensities to consider the performance of taller rack systems. In addition, a comprehensive discussion on the damping of the system is also provided based on the test results. The performance of the rack frame is described through an extensive set of measurements, including rack displacement, pallet sliding, the acceleration of a concrete block and rack frame and the damping of the system in the down-aisle direction. The results indicate that the standard rack frames are able to endure large inelastic deformations without loss of stability. Full article
(This article belongs to the Section Civil Engineering)
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22 pages, 1795 KiB  
Review
Trusted Academic Transcripts on the Blockchain: A Systematic Literature Review
by Giulio Caldarelli and Joshua Ellul
Appl. Sci. 2021, 11(4), 1842; https://doi.org/10.3390/app11041842 - 19 Feb 2021
Cited by 71 | Viewed by 15052
Abstract
Much of the excitement around blockchain is mainly due to promising applications in the financial sector. However, many also believe in the technology’s potential to disrupt non-financial sectors and applications, including supply chains, energy, e-voting, healthcare, and education. The application of blockchain within [...] Read more.
Much of the excitement around blockchain is mainly due to promising applications in the financial sector. However, many also believe in the technology’s potential to disrupt non-financial sectors and applications, including supply chains, energy, e-voting, healthcare, and education. The application of blockchain within the education sector is expected to make improvements to academic transcripts, credentials, digital libraries, and student records. Research in this domain is rapidly increasing, and current reviews summarize the proposed improvements. On the other hand, the analysis undertaken has remained at a general level that lacks the depth required to cover diverging proposals that have emerged. This review focuses on the application of blockchain for academic transcripts. The aim is to find, among the proposed models, converging aspects that resolve common challenges and may lead to a universally accepted de-facto standard. Furthermore, since academic institutions will serve as oracles to the particular blockchain applications, a discussion on their trustworthiness will be outlined to explore if the proposed applications efficiently address the oracle problem. The outcome of this review highlights the need for a standardized approach built on a public blockchain to promote faster adoption and acceptance. Furthermore, oracles should be incentivized in order for the system to be sustainable, while their identities and activities should be known and identifiable. Full article
(This article belongs to the Section Computing and Artificial Intelligence)
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16 pages, 1424 KiB  
Article
Blockchain-Based Secured Access Control in an IoT System
by Sultan Algarni, Fathy Eassa, Khalid Almarhabi, Abduallah Almalaise, Emad Albassam, Khalid Alsubhi and Mohammad Yamin
Appl. Sci. 2021, 11(4), 1772; https://doi.org/10.3390/app11041772 - 17 Feb 2021
Cited by 70 | Viewed by 6394
Abstract
The distributed nature of Internet of Things (IoT) and its rapid increase on a large scale raises many security and privacy issues. Access control is one of the major challenges currently addressed through centralized approaches that may rely on a third party and [...] Read more.
The distributed nature of Internet of Things (IoT) and its rapid increase on a large scale raises many security and privacy issues. Access control is one of the major challenges currently addressed through centralized approaches that may rely on a third party and they are constrained by availability and scalability, which may result in a performance bottleneck. Therefore, this paper proposes a novel solution to manage the delivery of lightweight and decentralized secure access control of an IoT system based on a multi-agent system and a blockchain. The main objective of the proposed solution is to build Blockchain Managers (BCMs) for securing IoT access control, as well as allowing for secure communication between local IoT devices. Moreover, the solution also enables secure communication between IoT devices, fog nodes and cloud computing. Full article
(This article belongs to the Section Computing and Artificial Intelligence)
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18 pages, 7035 KiB  
Review
Bioengineered Skin Substitutes: Advances and Future Trends
by Shima Tavakoli and Agnes S. Klar
Appl. Sci. 2021, 11(4), 1493; https://doi.org/10.3390/app11041493 - 7 Feb 2021
Cited by 70 | Viewed by 15380
Abstract
As the largest organ in the human body, the skin has the function of maintaining balance and protecting from external factors such as bacteria, chemicals, and temperature. If the wound does not heal in time after skin damage, it may cause infection or [...] Read more.
As the largest organ in the human body, the skin has the function of maintaining balance and protecting from external factors such as bacteria, chemicals, and temperature. If the wound does not heal in time after skin damage, it may cause infection or life-threatening complications. In particular, medical treatment of large skin defects caused by burns or trauma remains challenging. Therefore, human bioengineered skin substitutes represent an alternative approach to treat such injuries. Based on the chemical composition and scaffold material, skin substitutes can be classified into acellular or cellular grafts, as well as natural-based or synthetic skin substitutes. Further, they can be categorized as epidermal, dermal, and composite grafts, based on the skin component they contain. This review presents the common commercially available skin substitutes and their clinical use. Moreover, the choice of an appropriate hydrogel type to prepare cell-laden skin substitutes is discussed. Additionally, we present recent advances in the field of bioengineered human skin substitutes using three-dimensional (3D) bioprinting techniques. Finally, we discuss different skin substitute developments to meet different criteria for optimal wound healing. Full article
(This article belongs to the Special Issue Skin Tissue Engineering)
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23 pages, 12481 KiB  
Article
Hydrothermal and Entropy Investigation of Ag/MgO/H2O Hybrid Nanofluid Natural Convection in a Novel Shape of Porous Cavity
by Nidal Abu-Libdeh, Fares Redouane, Abderrahmane Aissa, Fateh Mebarek-Oudina, Ahmad Almuhtady, Wasim Jamshed and Wael Al-Kouz
Appl. Sci. 2021, 11(4), 1722; https://doi.org/10.3390/app11041722 - 15 Feb 2021
Cited by 68 | Viewed by 4217
Abstract
In this study, a new cavity form filled under a constant magnetic field by Ag/MgO/H2O nanofluids and porous media consistent with natural convection and total entropy is examined. The nanofluid flow is considered to be laminar and incompressible, while the advection [...] Read more.
In this study, a new cavity form filled under a constant magnetic field by Ag/MgO/H2O nanofluids and porous media consistent with natural convection and total entropy is examined. The nanofluid flow is considered to be laminar and incompressible, while the advection inertia effect in the porous layer is taken into account by adopting the Darcy–Forchheimer model. The problem is explained in the dimensionless form of the governing equations and solved by the finite element method. The results of the values of Darcy (Da), Hartmann (Ha) and Rayleigh (Ra) numbers, porosity (εp), and the properties of solid volume fraction (ϕ) and flow fields were studied. The findings show that with each improvement in the Ha number, the heat transfer rate becomes more limited, and thus the magnetic field can be used as an outstanding heat transfer controller. Full article
(This article belongs to the Special Issue Multiphase Modeling of Porous Media: Advances toward Widespread Applications)
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23 pages, 459 KiB  
Article
Cyber Ranges and TestBeds for Education, Training, and Research
by Nestoras Chouliaras, George Kittes, Ioanna Kantzavelou, Leandros Maglaras, Grammati Pantziou and Mohamed Amine Ferrag
Appl. Sci. 2021, 11(4), 1809; https://doi.org/10.3390/app11041809 - 18 Feb 2021
Cited by 67 | Viewed by 9953
Abstract
In recent years, there has been a growing demand for cybersecurity experts, and, according to predictions, this demand will continue to increase. Cyber Ranges can fill this gap by combining hands-on experience with educational courses, and conducting cybersecurity competitions. In this paper, we [...] Read more.
In recent years, there has been a growing demand for cybersecurity experts, and, according to predictions, this demand will continue to increase. Cyber Ranges can fill this gap by combining hands-on experience with educational courses, and conducting cybersecurity competitions. In this paper, we conduct a systematic survey of ten Cyber Ranges that were developed in the last decade, with a structured interview. The purpose of the interview is to find details about essential components, and especially the tools used to design, create, implement and operate a Cyber Range platform, and to present the findings. Full article
(This article belongs to the Special Issue Cyber Security of Critical Infrastructures)
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24 pages, 13130 KiB  
Review
Machine Learning for Design Optimization of Electromagnetic Devices: Recent Developments and Future Directions
by Yanbin Li, Gang Lei, Gerd Bramerdorfer, Sheng Peng, Xiaodong Sun and Jianguo Zhu
Appl. Sci. 2021, 11(4), 1627; https://doi.org/10.3390/app11041627 - 11 Feb 2021
Cited by 67 | Viewed by 11273
Abstract
This paper reviews the recent developments of design optimization methods for electromagnetic devices, with a focus on machine learning methods. First, the recent advances in multi-objective, multidisciplinary, multilevel, topology, fuzzy, and robust design optimization of electromagnetic devices are overviewed. Second, a review is [...] Read more.
This paper reviews the recent developments of design optimization methods for electromagnetic devices, with a focus on machine learning methods. First, the recent advances in multi-objective, multidisciplinary, multilevel, topology, fuzzy, and robust design optimization of electromagnetic devices are overviewed. Second, a review is presented to the performance prediction and design optimization of electromagnetic devices based on the machine learning algorithms, including artificial neural network, support vector machine, extreme learning machine, random forest, and deep learning. Last, to meet modern requirements of high manufacturing/production quality and lifetime reliability, several promising topics, including the application of cloud services and digital twin, are discussed as future directions for design optimization of electromagnetic devices. Full article
(This article belongs to the Special Issue Advanced Optimization Methods for the Design of Electromagnetic Devices)
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26 pages, 2518 KiB  
Review
New Tendencies in Wind Energy Operation and Maintenance
by Ángel M. Costa, José A. Orosa, Diego Vergara and Pablo Fernández-Arias
Appl. Sci. 2021, 11(4), 1386; https://doi.org/10.3390/app11041386 - 4 Feb 2021
Cited by 67 | Viewed by 16280
Abstract
Both the reduction in operating and maintenance (O&M) costs and improved reliability have become top priorities in wind turbine maintenance strategies. O&M costs typically account for 20% to 25% of the total levelized cost of electricity (LCOE) of current wind power systems. This [...] Read more.
Both the reduction in operating and maintenance (O&M) costs and improved reliability have become top priorities in wind turbine maintenance strategies. O&M costs typically account for 20% to 25% of the total levelized cost of electricity (LCOE) of current wind power systems. This paper provides a general review of the state of the art of research conducted on wind farm maintenance in recent years. It shows the new methods and techniques, focusing on trends and future challenges. In addition to this, this work includes a review of the following items: (i) operation and maintenance, (ii) failure rate, (iii) reliability, (iv) condition monitoring, (v) maintenance strategies, (vi) maintenance and life cycle and (vii) maintenance optimization As for offshore wind turbines, it is crucial to limit the maximum faults, since the maintenance of these wind farms is more complex both technically and logistically. Research into wind farm maintenance increased by 87% between 2007 and 2019, with more than 38,000 papers (Scopus) including “wind energy” as the main topic and some keywords related to O&M costs. The LCOE in onshore wind projects has decreased by 45%, while in offshore projects it has decreased by 28%. The O&M costs of onshore wind projects fell 52%, while in the case of offshore projects, they have declined 45%. Thus, the results obtained in this paper suggest that there is a change in research on wind farm operation and maintenance, as in recent years, scientific interest in failure has been increasing, while interest in the various techniques of wind farm maintenance and operation has been decreasing. Full article
(This article belongs to the Special Issue 10th Anniversary of Applied Sciences: Invited Papers in Energy Section)
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14 pages, 839 KiB  
Review
Biohydrogen from Microalgae: Production and Applications
by Antonina Rita Limongi, Emanuele Viviano, Maria De Luca, Rosa Paola Radice, Giuliana Bianco and Giuseppe Martelli
Appl. Sci. 2021, 11(4), 1616; https://doi.org/10.3390/app11041616 - 10 Feb 2021
Cited by 66 | Viewed by 10146
Abstract
The need to safeguard our planet by reducing carbon dioxide emissions has led to a significant development of research in the field of alternative energy sources. Hydrogen has proved to be the most promising molecule, as a fuel, due to its low environmental [...] Read more.
The need to safeguard our planet by reducing carbon dioxide emissions has led to a significant development of research in the field of alternative energy sources. Hydrogen has proved to be the most promising molecule, as a fuel, due to its low environmental impact. Even if various methods already exist for producing hydrogen, most of them are not sustainable. Thus, research focuses on the biological sector, studying microalgae, and other microorganisms’ ability to produce this precious molecule in a natural way. In this review, we provide a description of the biochemical and molecular processes for the production of biohydrogen and give a general overview of one of the most interesting technologies in which hydrogen finds application for electricity production: fuel cells. Full article
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26 pages, 1830 KiB  
Review
Towards Phase Change Materials for Thermal Energy Storage: Classification, Improvements and Applications in the Building Sector
by Christina V. Podara, Ioannis A. Kartsonakis and Costas A. Charitidis
Appl. Sci. 2021, 11(4), 1490; https://doi.org/10.3390/app11041490 - 6 Feb 2021
Cited by 66 | Viewed by 13112
Abstract
The management of energy consumption in the building sector is of crucial concern for modern societies. Fossil fuels’ reduced availability, along with the environmental implications they cause, emphasize the necessity for the development of new technologies using renewable energy resources. Taking into account [...] Read more.
The management of energy consumption in the building sector is of crucial concern for modern societies. Fossil fuels’ reduced availability, along with the environmental implications they cause, emphasize the necessity for the development of new technologies using renewable energy resources. Taking into account the growing resource shortages, as well as the ongoing deterioration of the environment, the building energy performance improvement using phase change materials (PCMs) is considered as a solution that could balance the energy supply together with the corresponding demand. Thermal energy storage systems with PCMs have been investigated for several building applications as they constitute a promising and sustainable method for reduction of fuel and electrical energy consumption, while maintaining a comfortable environment in the building envelope. These compounds can be incorporated into building construction materials and provide passive thermal sufficiency, or they can be used in heating, ventilation, and air conditioning systems, domestic hot water applications, etc. This study presents the principles of latent heat thermal energy storage systems with PCMs. Furthermore, the materials that can be used as PCMs, together with the most effective methods for improving their thermal performance, as well as various passive applications in the building sector, are also highlighted. Finally, special attention is given to the encapsulated PCMs that are composed of the core material, which is the PCM, and the shell material, which can be inorganic or organic, and their utilization inside constructional materials. Full article
(This article belongs to the Special Issue Phase Change Materials: Design and Applications)
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12 pages, 2750 KiB  
Article
Enhanced Electrokinetic Remediation for the Removal of Heavy Metals from Contaminated Soils
by Claudio Cameselle, Susana Gouveia and Adrian Cabo
Appl. Sci. 2021, 11(4), 1799; https://doi.org/10.3390/app11041799 - 18 Feb 2021
Cited by 63 | Viewed by 5730
Abstract
The electrokinetic remediation of an agricultural soil contaminated with heavy metals was studied using organic acids as facilitating agents. The unenhanced electrokinetic treatment using deionized water as processing fluid did not show any significant mobilization and removal of heavy metals due to the [...] Read more.
The electrokinetic remediation of an agricultural soil contaminated with heavy metals was studied using organic acids as facilitating agents. The unenhanced electrokinetic treatment using deionized water as processing fluid did not show any significant mobilization and removal of heavy metals due to the low solubilization of metals and precipitation at high pH conditions close to the cathode. EDTA and citric acid 0.1 M were used as facilitating agents to favor the dissolution and transportation of metals. The organic acids were added to the catholyte and penetrated into the soil specimen by electromigration. EDTA formed negatively charged complexes. Citric acid formed neutral metal complexes in the soil pH conditions (pH = 2–4). Citric acid was much more effective in the dissolution and transportation out of the soil specimen of complexed metals. In order to enhance the removal of metals, the concentration of citric acid was increased up to 0.5 M, resulting in the removal of 78.7% of Cd, 78.6% of Co, 72.5% of Cu, 73.3% of Zn, 11.8% of Cr and 9.8% of Pb. Full article
(This article belongs to the Special Issue Environmental Restoration of Metal-Contaminated Soils)
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21 pages, 534 KiB  
Review
Environmental Conditions and Agronomical Factors Influencing the Levels of Phytochemicals in Brassica Vegetables Responsible for Nutritional and Sensorial Properties
by Francesca Biondi, Francesca Balducci, Franco Capocasa, Marino Visciglio, Elena Mei, Massimo Vagnoni, Bruno Mezzetti and Luca Mazzoni
Appl. Sci. 2021, 11(4), 1927; https://doi.org/10.3390/app11041927 - 22 Feb 2021
Cited by 58 | Viewed by 6360
Abstract
Recently, the consumption of healthy foods has been related to the prevention of cardiovascular, degenerative diseases and different forms of cancers, underlying the importance of the diet for the consumer’s health. Fruits and vegetables contain phytochemicals that act as protective factors for the [...] Read more.
Recently, the consumption of healthy foods has been related to the prevention of cardiovascular, degenerative diseases and different forms of cancers, underlying the importance of the diet for the consumer’s health. Fruits and vegetables contain phytochemicals that act as protective factors for the human body, through different mechanisms of action. Among vegetables, Brassica received a lot of attention in the last years for the phytochemical compounds content and antioxidant capacity that confer nutraceutical value to the product. The amount of healthy bioactive compounds present in the Brassica defines the nutritional quality. These molecules could belong to the class of antioxidant compounds (e.g., phenols, vitamin C, etc.), or to non-antioxidant compounds (e.g., minerals, glucosinolates, etc.). The amount of these compounds in Brassica vegetables could be influenced by several factors, depending on the genotypes, the environmental conditions and the cultivation techniques adopted. The aim of this study is to highlight the main phytochemical compounds present in brassicas used as a food vegetable that confer nutritional and sensorial quality to the final product, and to investigate the main factors that affect the phytochemical concentration and the overall quality of Brassica vegetables. Full article
(This article belongs to the Special Issue Potential Health Benefits of Fruits and Vegetables)
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17 pages, 2794 KiB  
Article
Facile Hydrothermal and Solvothermal Synthesis and Characterization of Nitrogen-Doped Carbon Dots from Palm Kernel Shell Precursor
by Yakubu Newman Monday, Jaafar Abdullah, Nor Azah Yusof, Suraya Abdul Rashid and Rafidah Hanim Shueb
Appl. Sci. 2021, 11(4), 1630; https://doi.org/10.3390/app11041630 - 11 Feb 2021
Cited by 58 | Viewed by 5962
Abstract
Carbon dots (CDs), a nanomaterial synthesized from organic precursors rich in carbon content with excellent fluorescent property, are in high demand for many purposes, including sensing and biosensing applications. This research focused on preparing CDs from natural and abundant waste, palm kernel shells [...] Read more.
Carbon dots (CDs), a nanomaterial synthesized from organic precursors rich in carbon content with excellent fluorescent property, are in high demand for many purposes, including sensing and biosensing applications. This research focused on preparing CDs from natural and abundant waste, palm kernel shells (PKS) obtained from palm oil biomass, aiming for sensing and biosensing applications. Ethylenediamine and L-phenylalanine doped CDs were produced via the hydrothermal and solvothermal methods using one-pot synthesis techniques in an autoclave batch reactor. The as-prepared N-CDs shows excellent photoluminescence (PL) property and a quantum yield (QY) of 13.7% for ethylenediamine (EDA) doped N-CDs (CDs-EDA) and 8.6% for L-phenylalanine (L-Ph) doped N-CDs (CDs-LPh) with an excitation/emission wavelength of 360 nm/450 nm. The transmission electron microscopy (TEM) images show the N-CDs have an average particle size of 2 nm for both CDs. UV-Visible spectrophotometric results showed C=C and C=O transition. FTIR results show and confirm the presence of functional groups, such as -OH, -C=O, -NH2 on the N-CDs, and the X-ray diffraction pattern showed that the N-CDs were crystalline, depicted with sharp peaks. This research work demonstrated that palm kernel shell biomass often thrown away as waste can produce CDs with excellent physicochemical properties. Full article
(This article belongs to the Section Materials Science and Engineering)
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27 pages, 2935 KiB  
Review
Nanoparticles and Nanocrystals by Supercritical CO2-Assisted Techniques for Pharmaceutical Applications: A Review
by Paola Franco and Iolanda De Marco
Appl. Sci. 2021, 11(4), 1476; https://doi.org/10.3390/app11041476 - 6 Feb 2021
Cited by 57 | Viewed by 8038
Abstract
Many active ingredients currently prescribed show limited therapeutic efficacy, mainly due to their dissolution rate inadequate to treat the pathology of interest. A large drug particle size creates an additional problem if a specific site of action in the human body has to [...] Read more.
Many active ingredients currently prescribed show limited therapeutic efficacy, mainly due to their dissolution rate inadequate to treat the pathology of interest. A large drug particle size creates an additional problem if a specific site of action in the human body has to be reached. For this reason, active ingredient size reduction using micronization/nanonization techniques is a valid approach to improve the efficacy of active compounds. Supercritical carbon-dioxide-assisted technologies enable the production of different morphologies of different sizes, including nanoparticles and nanocrystals, by modulating operating conditions. Supercritical fluid-based processes have numerous advantages over techniques conventionally employed to produce nanosized particles or crystals, such as reduced use of toxic solvents, which are completely removed from the final product, ensuring safety for patients. Active compounds can be processed alone by supercritical techniques, although polymeric carriers are often added as stabilizers, to control the drug release on the basis of the desired therapeutic effect, as well as to improve drug processability with the chosen technology. This updated review on the application of supercritical micronization/nanonization techniques in the pharmaceutical field aims at highlighting the most effective current results, operating conditions, advantages, and limitations, providing future perspectives. Full article
(This article belongs to the Special Issue Applications of Nanoparticles in Pharmaceuticals)
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16 pages, 318 KiB  
Article
Trends and Challenges in Network Covert Channels Countermeasures
by Luca Caviglione
Appl. Sci. 2021, 11(4), 1641; https://doi.org/10.3390/app11041641 - 11 Feb 2021
Cited by 54 | Viewed by 10693
Abstract
Network covert channels are increasingly used to endow malware with stealthy behaviors, for instance to exfiltrate data or to orchestrate nodes of a botnet in a cloaked manner. Unfortunately, the detection of such attacks is difficult as network covert channels are often characterized [...] Read more.
Network covert channels are increasingly used to endow malware with stealthy behaviors, for instance to exfiltrate data or to orchestrate nodes of a botnet in a cloaked manner. Unfortunately, the detection of such attacks is difficult as network covert channels are often characterized by low data rates and defenders do not know in advance where the secret information has been hidden. Moreover, neutralization or mitigation are hard tasks, as they require to not disrupt legitimate flows or degrade the quality perceived by users. As a consequence, countermeasures are tightly coupled to specific channel architectures, leading to poorly generalizable and often scarcely scalable approaches. In this perspective, this paper investigates trends and challenges in the development of countermeasures against the most popular network covert channels. To this aim, we reviewed the relevant literature by considering approaches that can be effectively deployed to detect general injection mechanisms or threats observed in the wild. Emphasis has been put on enlightening trajectories that should be considered when engineering mitigation techniques or planning the research to face the increasing wave of information-hiding-capable malware. Results indicate that many works are extremely specialized and an effective strategy for taming security risks caused by network covert channels may benefit from high-level and general approaches. Moreover, mechanisms to prevent the exploitation of ambiguities should be already considered in early design phases of both protocols and services. Full article
(This article belongs to the Special Issue Data Hiding and Its Applications: Digital Watermarking and Steganography)
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19 pages, 4843 KiB  
Article
Application of Artificial Intelligence to Determined Unconfined Compressive Strength of Cement-Stabilized Soil in Vietnam
by Huong Thi Thanh Ngo, Tuan Anh Pham, Huong Lan Thi Vu and Loi Van Giap
Appl. Sci. 2021, 11(4), 1949; https://doi.org/10.3390/app11041949 - 23 Feb 2021
Cited by 52 | Viewed by 4159
Abstract
Cement stabilized soil is one of the commonly used as ground reinforcement solutions in geotechnical engineering. In this study, the main object was to apply three machine learning (ML) methods namely gradient boosting (GB), artificial neural network (ANN) and support vector machine (SVM) [...] Read more.
Cement stabilized soil is one of the commonly used as ground reinforcement solutions in geotechnical engineering. In this study, the main object was to apply three machine learning (ML) methods namely gradient boosting (GB), artificial neural network (ANN) and support vector machine (SVM) to predict unconfined compressive strength (UCS) of cement stabilized soil. Soil samples were collected at Hai Duong city, Vietnam. A total of 216 soil–cement samples were mixed in the laboratory and compressed to determine the UCS. This data set is divided into two parts of the training data set (80%) and testing set (20%) to build and test the model, respectively. To verify the performance of ML model, various criteria named correlation coefficient (R), mean absolute error (MAE) and root mean square error (RMSE) were used. The results show that all three ML models were effective methods to predict the UCS of cement-stabilized soil. Amongst three model used in this study, optimized ANN model provided superior performance compare to two others models with performance indicator R = 0.925, RMSE = 419.82 and MAE = 292.2 for testing part. This study can provide an effective tool to quickly predict the UCS of cement stabilized soil with high accuracy. Full article
(This article belongs to the Section Civil Engineering)
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27 pages, 8909 KiB  
Review
Crowded Space: A Review on Radar Measurements for Space Debris Monitoring and Tracking
by Giacomo Muntoni, Giorgio Montisci, Tonino Pisanu, Pietro Andronico and Giuseppe Valente
Appl. Sci. 2021, 11(4), 1364; https://doi.org/10.3390/app11041364 - 3 Feb 2021
Cited by 52 | Viewed by 9675
Abstract
Space debris monitoring is nowadays a priority for worldwide space agencies, due to the serious threat that these objects present. More and more efforts have been made to extend the network of available radar systems devoted to the control of space. A meticulous [...] Read more.
Space debris monitoring is nowadays a priority for worldwide space agencies, due to the serious threat that these objects present. More and more efforts have been made to extend the network of available radar systems devoted to the control of space. A meticulous review has been done in this paper, in order to find and classify the considerable amounts of data provided by the scientific community that deal with RADAR measurement for the debris monitoring and tracking. The information gathered is organized based on the volume of found data and classified taking into account the geographical location of the facilities. Full article
(This article belongs to the Special Issue Space Debris: Monitoring and Hazard Evaluation)
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19 pages, 6177 KiB  
Article
A Study of Multilayer Perceptron Networks Applied to Classification of Ceramic Insulators Using Ultrasound
by Nemesio Fava Sopelsa Neto, Stéfano Frizzo Stefenon, Luiz Henrique Meyer, Rafael Bruns, Ademir Nied, Laio Oriel Seman, Gabriel Villarrubia Gonzalez, Valderi Reis Quietinho Leithardt and Kin-Choong Yow
Appl. Sci. 2021, 11(4), 1592; https://doi.org/10.3390/app11041592 - 10 Feb 2021
Cited by 49 | Viewed by 4584
Abstract
Interruptions in the supply of electricity cause numerous losses to consumers, whether residential or industrial and may result in fines being imposed on the regulatory agency’s concessionaire. In Brazil, the electrical transmission and distribution systems cover a large territorial area, and because they [...] Read more.
Interruptions in the supply of electricity cause numerous losses to consumers, whether residential or industrial and may result in fines being imposed on the regulatory agency’s concessionaire. In Brazil, the electrical transmission and distribution systems cover a large territorial area, and because they are usually outdoors, they are exposed to environmental variations. In this context, periodic inspections are carried out on the electrical networks, and ultrasound equipment is widely used, due to non-destructive analysis characteristics. Ultrasonic inspection allows the identification of defective insulators based on the signal interpreted by an operator. This task fundamentally depends on the operator’s experience in this interpretation. In this way, it is intended to test machine learning applications to interpret ultrasound signals obtained from electrical grid insulators, distribution, class 25 kV. Currently, research in the area uses several models of artificial intelligence for various types of evaluation. This paper studies Multilayer Perceptron networks’ application to the classification of the different conditions of ceramic insulators based on a restricted database of ultrasonic signals recorded in the laboratory. Full article
(This article belongs to the Special Issue Applied Artificial Intelligence (AI))
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14 pages, 3303 KiB  
Article
Automatic Identification of Peanut-Leaf Diseases Based on Stack Ensemble
by Haixia Qi, Yu Liang, Quanchen Ding and Jun Zou
Appl. Sci. 2021, 11(4), 1950; https://doi.org/10.3390/app11041950 - 23 Feb 2021
Cited by 48 | Viewed by 4597
Abstract
Peanut is an important food crop, and diseases of its leaves can directly reduce its yield and quality. In order to solve the problem of automatic identification of peanut-leaf diseases, this paper uses a traditional machine-learning method to ensemble the output of a [...] Read more.
Peanut is an important food crop, and diseases of its leaves can directly reduce its yield and quality. In order to solve the problem of automatic identification of peanut-leaf diseases, this paper uses a traditional machine-learning method to ensemble the output of a deep learning model to identify diseases of peanut leaves. The identification of peanut-leaf diseases included healthy leaves, rust disease on a single leaf, leaf-spot disease on a single leaf, scorch disease on a single leaf, and both rust disease and scorch disease on a single leaf. Three types of data-augmentation methods were used: image flipping, rotation, and scaling. In this experiment, the deep-learning model had a higher accuracy than the traditional machine-learning methods. Moreover, the deep-learning model achieved better performance when using data augmentation and a stacking ensemble. After ensemble by logistic regression, the accuracy of residual network with 50 layers (ResNet50) was as high as 97.59%, and the F1 score of dense convolutional network with 121 layers (DenseNet121) was as high as 90.50. The deep-learning model used in this experiment had the greatest improvement in F1 score after the logistic regression ensemble. Deep-learning networks with deeper network layers like ResNet50 and DenseNet121 performed better in this experiment. This study can provide a reference for the identification of peanut-leaf diseases. Full article
(This article belongs to the Section Food Science and Technology)
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14 pages, 4559 KiB  
Article
A Practical and Effective Layout for a Safe Human-Robot Collaborative Assembly Task
by Leonardo Sabatino Scimmi, Matteo Melchiorre, Mario Troise, Stefano Mauro and Stefano Pastorelli
Appl. Sci. 2021, 11(4), 1763; https://doi.org/10.3390/app11041763 - 17 Feb 2021
Cited by 48 | Viewed by 5356
Abstract
This work describes a layout to carry out a demonstrative assembly task, during which a collaborative robot performs pick-and-place tasks to supply an operator the parts that he/she has to assemble. In this scenario, the robot and operator share the workspace and a [...] Read more.
This work describes a layout to carry out a demonstrative assembly task, during which a collaborative robot performs pick-and-place tasks to supply an operator the parts that he/she has to assemble. In this scenario, the robot and operator share the workspace and a real time collision avoidance algorithm is implemented to modify the planned trajectories of the robot avoiding any collision with the human worker. The movements of the operator are tracked by two Microsoft Kinect v2 sensors to overcome problems related with occlusions and poor perception of a single camera. The data obtained by the two Kinect sensors are combined and then given as input to the collision avoidance algorithm. The experimental results show the effectiveness of the collision avoidance algorithm and the significant gain in terms of task times that the highest level of human-robot collaboration can bring. Full article
(This article belongs to the Special Issue Smart Robots for Industrial Applications)
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17 pages, 1454 KiB  
Review
Nano-Elicitation as an Effective and Emerging Strategy for In Vitro Production of Industrially Important Flavonoids
by Amna Komal Khan, Sidra Kousar, Duangjai Tungmunnithum, Christophe Hano, Bilal Haider Abbasi and Sumaira Anjum
Appl. Sci. 2021, 11(4), 1694; https://doi.org/10.3390/app11041694 - 14 Feb 2021
Cited by 48 | Viewed by 6134
Abstract
Flavonoids represent a popular class of industrially important bioactive compounds. They possess valuable health-benefiting and disease preventing properties, and therefore they are an important component of the pharmaceutical, nutraceutical, cosmetical and medicinal industries. Moreover, flavonoids possess significant antiallergic, antihepatotoxic, anti-inflammatory, antioxidant, antitumor, antiviral, [...] Read more.
Flavonoids represent a popular class of industrially important bioactive compounds. They possess valuable health-benefiting and disease preventing properties, and therefore they are an important component of the pharmaceutical, nutraceutical, cosmetical and medicinal industries. Moreover, flavonoids possess significant antiallergic, antihepatotoxic, anti-inflammatory, antioxidant, antitumor, antiviral, and antibacterial as well as cardio-protective activities. Due to these properties, there is a rise in global demand for flavonoids, forming a significant part of the world market. However, obtaining flavonoids directly from plants has some limitations, such as low quantity, poor extraction, over-exploitation, time consuming process and loss of flora. Henceforth, there is a shift towards the in vitro production of flavonoids using the plant tissue culture technique to achieve better yields in less time. In order to achieve the productivity of flavonoids at an industrially competitive level, elicitation is a useful tool. The elicitation of in vitro cultures induces stressful conditions to plants, activates the plant defense system and enhances the accumulation of secondary metabolites in higher quantities. In this regard, nanoparticles (NPs) have emerged as novel and effective elicitors for enhancing the in vitro production of industrially important flavonoids. Different classes of NPs, including metallic NPs (silver and copper), metallic oxide NPs (copper oxide, iron oxide, zinc oxide, silicon dioxide) and carbon nanotubes, are widely reported as nano-elicitors of flavonoids discussed herein. Lastly, the mechanisms of NPs as well as knowledge gaps in the area of the nano-elicitation of flavonoids have been highlighted in this review. Full article
(This article belongs to the Special Issue Industrial Applications of Flavonoids: Current Uses and Future Trends)
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