Materials

22 pages, 17392 KiB

Open AccessEditor’s ChoiceArticle

Characterization and Design of Three-Phase Particulate Composites: Microstructure-Free Finite Element Modeling vs. Analytical Micromechanics Models

by Sebak Oli and Yunhua Luo

Materials 2023, 16(18), 6147; https://doi.org/10.3390/ma16186147 - 10 Sep 2023

Viewed by 1594

Abstract

Three-phase particulate composites offer greater design flexibility in the selection of phase materials and have more design variables than their two-phase counterparts, thus providing larger space for tailoring effective properties to meet intricate engineering requirements. Predicting effective elastic properties is essential for composite [...] Read more.

Three-phase particulate composites offer greater design flexibility in the selection of phase materials and have more design variables than their two-phase counterparts, thus providing larger space for tailoring effective properties to meet intricate engineering requirements. Predicting effective elastic properties is essential for composite design. However, experimental methods are both expensive and time intensive, whereas the scope of analytical micromechanics models is limited by their inherent assumptions. The newly developed microstructure-free finite element modeling (MF-FEM) approach has been demonstrated to be accurate and reliable for two-phase particulate composites. In this study, we investigate whether the MF-FEM approach can be applied to three-phase particulate composites and, if applicable, under which conditions. The study commences with a convergence analysis to establish the threshold ratio between the element size and the RVE (representative volume element) dimension. We then validate the MF-FEM approach using experimental data on three-phase composites from the existing literature. Subsequently, the MF-FEM method serves as a benchmark to assess the accuracy of both traditional and novel analytical micromechanics models, in predicting the effective elasticity of two distinct types of three-phase particulate composites, characterized by their small and large phase contrasts, respectively. We found that the threshold element-to-RVE ratio (1/150) for three-phase composites is considerably smaller than the ratio (1/50) for two-phase composites. The validation underscores that MF-FEM predictions align closely with experimental data. The analytical micromechanics models demonstrate varying degrees of accuracy depending on the phase volume fractions and the contrast in phase properties. The study indicates that the analytical micromechanics models may not be dependable for predicting effective properties of three-phase particulate composites, particularly those with a large contrast in phase properties. Even though more time-intensive, the MF-FEM proves to be a more reliable approach than the analytical models. Full article

(This article belongs to the Special Issue Finite Element Modeling of Microstructures in Composite Materials)

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21 pages, 6351 KiB

Open AccessEditor’s ChoiceArticle

From Bioresources to Thermal Insulation Materials: Synthesis and Properties of Two-Component Open-Cell Spray Polyurethane Foams Based on Bio-Polyols from Used Cooking Oil

by Krzysztof Polaczek, Maria Kurańska, Elżbieta Malewska, Małgorzata Czerwicka-Pach and Aleksander Prociak

Materials 2023, 16(18), 6139; https://doi.org/10.3390/ma16186139 - 9 Sep 2023

Cited by 7 | Viewed by 2988

Abstract

Open-cell spray polyurethane foams are widely used as highly efficient thermal insulation materials with vapor permeability and soundproofing properties. Unfortunately, for the production of commercial foams, mainly non-renewable petrochemical raw materials are used. The aim of this study was to determine the possibility [...] Read more.

Open-cell spray polyurethane foams are widely used as highly efficient thermal insulation materials with vapor permeability and soundproofing properties. Unfortunately, for the production of commercial foams, mainly non-renewable petrochemical raw materials are used. The aim of this study was to determine the possibility of completely replacing petrochemical polyols (the main raw material used in the synthesis of polyurethanes, alongside isocyanates) with bio-polyols obtained from used cooking oils, classified as waste materials. The research consisted of three stages: the synthesis of bio-polyols, the development of polyurethane foam systems under laboratory conditions, and the testing of developed polyurethane spray systems under industrial conditions. The synthesis of the bio-polyols was carried out by using two different methods: a one-step transesterification process using triethanolamine and a two-step process of epoxidation and opening oxirane rings with diethylene glycol. The obtained bio-polyols were analyzed using gel chromatography and nuclear magnetic resonance spectroscopy. The developed polyurethane foam formulations included two types of fire retardants: halogenated tris(1-chloro-2-propyl) phosphate (TCPP) and halogen-free triethyl phosphate (TEP). In the formulations of polyurethane systems, reactive amine catalysts were employed, which become incorporated into the polymer matrix during foaming, significantly reducing their emission after application. The foams were manufactured on both a laboratory and industrial scale using high-pressure spray machines under conditions recommended by commercial system manufacturers: spray pressure 80–100 bar, component temperature 45–52 °C, and component volumetric ratio 1:1. The open-cell foams had apparent densities 14–21.5 kg/m³, thermal conductivity coefficients 35–38 mW/m∙K, closed-cell contents <5%, water vapor diffusion resistance factors (μ) <6, and limiting oxygen indexes 21.3–21.5%. The properties of the obtained foams were comparable to commercial materials. The developed polyurethane spray systems can be used as thermal insulation materials for insulating interior walls, attics, and ceilings. Full article

(This article belongs to the Special Issue Advances in Development and Characterization of Polyurethane Foams)

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15 pages, 6302 KiB

Open AccessEditor’s ChoiceArticle

Advanced Fabrication Method and Mechanical Properties of Silicon Nitride/Boron Nitride Fibrous Monolithic Ceramics

by Qingqing Chen, Yuan Zhang, Liuxin Chao, Ningning Dong, Yu Zhou and Guobing Ying

Materials 2023, 16(18), 6130; https://doi.org/10.3390/ma16186130 - 8 Sep 2023

Cited by 4 | Viewed by 2104

Abstract

Silicon nitride ceramics are regarded as a promising material for high-temperature structural applications due to their remarkable characteristics, including high strength, hardness, thermal conductivity, low dielectric properties, and resistance to creep at elevated temperatures. However, their susceptibility to catastrophic fracture at high temperatures [...] Read more.

Silicon nitride ceramics are regarded as a promising material for high-temperature structural applications due to their remarkable characteristics, including high strength, hardness, thermal conductivity, low dielectric properties, and resistance to creep at elevated temperatures. However, their susceptibility to catastrophic fracture at high temperatures remains a concern. Herein, Si₃N₄/BN fibrous monolithic ceramics have been successfully prepared by employing wet-spinning and hot-pressing techniques. We delved into the design and optimization of the spinning slurry and examined how the Si₃N₄/BN fiber diameter affects the ceramics’ microstructure and mechanical properties. The spinning slurry exhibited exceptional stability and spinnability. Decreasing the fiber diameter contributed to material densification and improved mechanical properties. Notably, when the fiber diameter is 0.9 mm, the fabricated Si₃N₄/BN fibrous monolithic ceramics demonstrate a carbon content of 0.82%, a three-point bending strength of 357 ± 24 MPa, and a fracture toughness of 8.8 ± 0.36 MPa·m^1/2. This investigation offers valuable insights into producing high-performance Si₃N₄/BN composite ceramics utilizing hot-pressing technology. Full article

(This article belongs to the Special Issue Advanced Ceramics Composites and Its Applications)

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9 pages, 2255 KiB

Open AccessEditor’s ChoiceArticle

DFT Calculation of Carbon-Doped TiO₂ Nanocomposites

by Kim Robert Gustavsen, Tao Feng, Hao Huang, Gang Li, Urszula Narkiewicz and Kaiying Wang

Materials 2023, 16(18), 6117; https://doi.org/10.3390/ma16186117 - 7 Sep 2023

Cited by 11 | Viewed by 2986

Abstract

Titanium dioxide (TiO₂) has been proven to be an excellent material for mitigating the continuous impact of elevated carbon dioxide concentrations. Carbon doping has emerged as a promising strategy to enhance the CO₂ reduction performance of TiO₂. In [...] Read more.

Titanium dioxide (TiO₂) has been proven to be an excellent material for mitigating the continuous impact of elevated carbon dioxide concentrations. Carbon doping has emerged as a promising strategy to enhance the CO₂ reduction performance of TiO₂. In this study, we investigated the effects of carbon doping on TiO₂ using density functional theory (DFT) calculations. Two carbon doping concentrations were considered (4% and 6%), denoted as TiO₂-2C and TiO₂-3C, respectively. The results showed that after carbon doping, the band gaps of TiO₂-2C and TiO₂-3C were reduced to 1.58 eV and 1.47 eV, respectively, which is lower than the band gap of pure TiO₂ (2.13 eV). This indicates an effective improvement in the electronic structure of TiO₂. Barrier energy calculations revealed that compared to pure TiO₂ (0.65 eV), TiO₂-2C (0.54 eV) and TiO₂-3C (0.59 eV) exhibited lower energy barriers, facilitating the transition to *COOH intermediates. These findings provide valuable insights into the electronic structure changes induced by carbon doping in TiO₂, which can contribute to the development of sustainable energy and environmental conservation measures to address global climate challenges. Full article

(This article belongs to the Section Materials Physics)

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13 pages, 799 KiB

Open AccessEditor’s ChoiceArticle

Numerical Simulation of PFRC Fracture Subjected to High Temperature by Means of a Trilinear Softening Diagram

by Fernando Suárez, Alejandro Enfedaque, Marcos G. Alberti and Jaime C. Gálvez

Materials 2023, 16(17), 6048; https://doi.org/10.3390/ma16176048 - 3 Sep 2023

Cited by 1 | Viewed by 1362

Abstract

Fibre-reinforced concrete (FRC) has been used for decades in certain applications in the construction industry, such as tunnel linings and precast elements, but has experienced important progress in recent times, boosted by the inclusion of guidelines for its use in some national and [...] Read more.

Fibre-reinforced concrete (FRC) has been used for decades in certain applications in the construction industry, such as tunnel linings and precast elements, but has experienced important progress in recent times, boosted by the inclusion of guidelines for its use in some national and international standards. Traditional steel fibres have been studied in depth and their performance is well-known, although in recent years new materials have been proposed as possible alternatives. Polyolefin macro-fibres, for instance, have been proven to enhance the mechanical properties of concrete and the parameters that define their behaviour (fibre length, fibre proportion or casting method, for instance) have been identified. These fibres overcome certain traditional problems related to steel fibres, such as corrosion or their interaction with magnetic fields, which can limit the use of steel in some applications. The behaviour of polyolefin fibre-reinforced concrete (PFRC) has been numerically reproduced with success through an embedded cohesive crack formulation that uses a trilinear softening diagram to describe the fracture behaviour of the material. Furthermore, concrete behaves well under high temperatures or fire events, especially when it is compared with other construction materials, but the behaviour of PFRC must be analysed if the use of these fibres is to be extended. To this end, the degradation of PFRC fracture properties has been recently experimentally analysed under a temperature range between 20 °C and 200 °C. As temperature increases, polyolefin fibres modify their mechanical properties and their shape, which reduce their performance as reinforcements of concrete. In this work, those experimental results, which include results of low (3 kg/m³) and high (10 kg/m³) proportion PFRC specimens, are used as reference to study the fracture behaviour of PFRC exposed to high temperatures from a numerical point of view. The experimental load-deflection diagrams are reproduced by modifying the trilinear diagram used in the cohesive model, which helps to understand how the trilinear diagram parameters are affected by high temperature exposure. Finally, some expressions are proposed to adapt the initial trilinear diagram (obtained with specimens not exposed to high temperature) in order to numerically reproduce the fracture behaviour of PFRC affected by high temperature exposure. Full article

(This article belongs to the Section Materials Simulation and Design)

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12 pages, 17002 KiB

Open AccessEditor’s ChoiceArticle

Influence of Lattice Mismatch on Structural and Functional Properties of Epitaxial Ba_0.7Sr_0.3TiO₃ Thin Films

by Jonas Wawra, Kornelius Nielsch and Ruben Hühne

Materials 2023, 16(17), 6036; https://doi.org/10.3390/ma16176036 - 2 Sep 2023

Cited by 5 | Viewed by 1910

Abstract

Substrate-induced strains can significantly influence the structural properties of epitaxial thin films. In ferroelectrics, this might lead to significant changes in the functional properties due to the strong electromechanical coupling in those materials. To study this in more detail, epitaxial Ba

_{0.7}

Sr [...] Read more.

Substrate-induced strains can significantly influence the structural properties of epitaxial thin films. In ferroelectrics, this might lead to significant changes in the functional properties due to the strong electromechanical coupling in those materials. To study this in more detail, epitaxial Ba

_{0.7}

Sr

_{0.3}

TiO

_{3}

films, which have a perovskite structure and a structural phase transition close to room temperature, were grown with different thicknesses on REScO

_{3}

(RE–rare earth element) substrates having a smaller lattice mismatch compared to SrTiO

_{3}

. A fully strained SrRuO

_{3}

bottom electrode and Pt top contacts were used to achieve a capacitor-like architecture. Different X-ray diffraction techniques were applied to study the microstructure of the films. Epitaxial films with a higher crystalline quality were obtained on scandates in comparison to SrTiO

_{3}

, whereas the strain state of the functional layer was strongly dependent on the chosen substrate and the thickness. Differences in permittivity and a non-linear polarization behavior were observed at higher temperatures, suggesting that ferroelectricity is supressed under tensile strain conditions in contrast to compressive strain for our measurement configuration, while a similar reentrant relaxor-like behavior was found in all studied layers below 0

° C

. Full article

(This article belongs to the Special Issue Ferromagnetic and Ferroelectric Materials: Synthesis, Applications, and Techniques)

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13 pages, 5756 KiB

Open AccessEditor’s ChoiceArticle

Microstructure and Corrosion Behavior of Laser-Welded Al–Mn–Zr Alloy for Heat Exchanger

by Jeong-Min Lim, Yoon-Sik So and Jung-Gu Kim

Materials 2023, 16(17), 6009; https://doi.org/10.3390/ma16176009 - 1 Sep 2023

Cited by 3 | Viewed by 1932

Abstract

In this study, an Al–Mn–Zr alloy was designed and its microstructure and corrosion behavior compared after laser welding to that of AA3003. As the results of immersion and electrochemical tests showed, both alloys had a faster corrosion rate in the fusion zone than [...] Read more.

In this study, an Al–Mn–Zr alloy was designed and its microstructure and corrosion behavior compared after laser welding to that of AA3003. As the results of immersion and electrochemical tests showed, both alloys had a faster corrosion rate in the fusion zone than in the base metal. Laser welding caused interdendritic segregation, and spread the intermetallic compounds (IMCs) evenly throughout in the fusion zone. This increased the micro-galvanic corrosion sites and destabilized the passive film, thus increasing the corrosion rate of the fusion zone. However, Zr in the Al–Mn alloy reduced the size and number of IMCs, and minimized the micro-galvanic corrosion effect. Consequently, Al–Mn–Zr alloy has higher corrosion resistance than AA3003 even after laser welding. Full article

(This article belongs to the Special Issue Investigation of Microstructural and Corrosion Properties of Steels and Light Alloys)

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20 pages, 3751 KiB

Open AccessEditor’s ChoiceArticle

Molecular Mechanism of the Piezoelectric Response in the β-Phase PVDF Crystals Interpreted by Periodic Boundary Conditions DFT Calculations

by Gianluca Serra, Alessia Arrigoni, Mirella Del Zoppo, Chiara Castiglioni and Matteo Tommasini

Materials 2023, 16(17), 6004; https://doi.org/10.3390/ma16176004 - 31 Aug 2023

Cited by 7 | Viewed by 2000

Abstract

A theoretical approach based on Periodic Boundary Conditions (PBC) and a Linear Combination of Atomic Orbitals (LCAO) in the framework of the density functional theory (DFT) is used to investigate the molecular mechanism that rules the piezoelectric behavior of poly(vinylidene fluoride) (PVDF) polymer [...] Read more.

A theoretical approach based on Periodic Boundary Conditions (PBC) and a Linear Combination of Atomic Orbitals (LCAO) in the framework of the density functional theory (DFT) is used to investigate the molecular mechanism that rules the piezoelectric behavior of poly(vinylidene fluoride) (PVDF) polymer in the crystalline β-phase. We present several computational tests highlighting the peculiar electrostatic potential energy landscape the polymer chains feel when they change their orientation by a rigid rotation in the lattice cell. We demonstrate that a rotation of the permanent dipole through chain rotation has a rather low energy cost and leads to a lattice relaxation. This justifies the macroscopic strain observed when the material is subjected to an electric field. Moreover, we investigate the effect on the molecular geometry of the expansion of the lattice parameters in the (a, b) plane, proving that the rotation of the dipole can take place spontaneously under mechanical deformation. By band deconvolution of the IR and Raman spectra of a PVDF film with a high content of β-phase, we provide the experimental phonon wavenumbers and relative band intensities, which we compare against the predictions from DFT calculations. This analysis shows the reliability of the LCAO approach, as implemented in the CRYSTAL software, for calculating the vibrational spectra. Finally, we investigate how the IR/Raman spectra evolve as a function of inter-chain distance, moving towards the isolated chain limit and to the limit of a single crystal slab. The results show the relevance of the inter-molecular interactions on the vibrational dynamics and on the electro-optical features ruling the intensity pattern of the vibrational spectra. Full article

(This article belongs to the Special Issue Density Functional Theory and Its Applications in Materials Science: A Critical Comparison between Theoretical Modelling of Crystals and Experiments)

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28 pages, 7377 KiB

Open AccessEditor’s ChoiceReview

A Review of Metamaterials in Wireless Power Transfer

by Cancan Rong, Lihui Yan, Long Li, Yunhui Li and Minghai Liu

Materials 2023, 16(17), 6008; https://doi.org/10.3390/ma16176008 - 31 Aug 2023

Cited by 19 | Viewed by 4273

Abstract

Wireless power transfer (WPT) is a technology that enables energy transmission without physical contact, utilizing magnetic and electric fields as soft media. While WPT has numerous applications, the increasing power transfer distance often results in a decrease in transmission efficiency, as well as [...] Read more.

Wireless power transfer (WPT) is a technology that enables energy transmission without physical contact, utilizing magnetic and electric fields as soft media. While WPT has numerous applications, the increasing power transfer distance often results in a decrease in transmission efficiency, as well as the urgent need for addressing safety concerns. Metamaterials offer a promising way for improving efficiency and reducing the flux density in WPT systems. This paper provides an overview of the current status and technical challenges of metamaterial-based WPT systems. The basic principles of magnetic coupling resonant wireless power transfer (MCR-WPT) are presented, followed by a detailed description of the metamaterial design theory and its application in WPT. The paper then reviews the metamaterial-based wireless energy transmission system from three perspectives: transmission efficiency, misalignment tolerance, and electromagnetic shielding. Finally, the paper summarizes the development trends and technical challenges of metamaterial-based WPT systems. Full article

(This article belongs to the Special Issue Metamaterials for Wireless Power Transfer)

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31 pages, 7958 KiB

Open AccessEditor’s ChoiceReview

Electrospun Nanofibers for Functional Food Packaging Application

by Meng Zhang, Adnan Ahmed and Lan Xu

Materials 2023, 16(17), 5937; https://doi.org/10.3390/ma16175937 - 30 Aug 2023

Cited by 26 | Viewed by 5598

Abstract

With the strengthening of the public awareness of food safety and environmental protection, functional food packaging materials have received widespread attention. Nanofibers are considered as promising packaging materials due to their unique one-dimensional structure (high aspect ratio, large specific surface area) and functional [...] Read more.

With the strengthening of the public awareness of food safety and environmental protection, functional food packaging materials have received widespread attention. Nanofibers are considered as promising packaging materials due to their unique one-dimensional structure (high aspect ratio, large specific surface area) and functional advantages. Electrospinning, as a commonly used simple and efficient method for preparing nanofibers, can obtain nanofibers with different structures such as aligned, core-shell, and porous structures by modifying the devices and adjusting the process parameters. The selection of raw materials and structural design of nanofibers can endow food packaging with different functions, including antimicrobial activity, antioxidation, ultraviolet protection, and response to pH. This paper aims to provide a comprehensive review of the application of electrospun nanofibers in functional food packaging. Advances in electrospinning technology and electrospun materials used for food packaging are introduced. Moreover, the progress and development prospects of electrospun nanofibers in functional food packaging are highlighted. Meanwhile, the application of functional packaging based on nanofibers in different foods is discussed in detail. Full article

(This article belongs to the Special Issue Functional Cellulosic Materials)

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18 pages, 4899 KiB

Open AccessEditor’s ChoiceReview

Wearable Temperature Sensors Based on Reduced Graphene Oxide Films

by Xinyue Li, Tianrui Cui, Xin Li, Houfang Liu, Ding Li, Jinming Jian, Zhen Li, Yi Yang and Tianling Ren

Materials 2023, 16(17), 5952; https://doi.org/10.3390/ma16175952 - 30 Aug 2023

Cited by 4 | Viewed by 2525

Abstract

With the development of medical technology and increasing demands of healthcare monitoring, wearable temperature sensors have gained widespread attention because of their portability, flexibility, and capability of conducting real-time and continuous signal detection. To achieve excellent thermal sensitivity, high linearity, and a fast [...] Read more.

With the development of medical technology and increasing demands of healthcare monitoring, wearable temperature sensors have gained widespread attention because of their portability, flexibility, and capability of conducting real-time and continuous signal detection. To achieve excellent thermal sensitivity, high linearity, and a fast response time, the materials of sensors should be chosen carefully. Thus, reduced graphene oxide (rGO) has become one of the most popular materials for temperature sensors due to its exceptional thermal conductivity and sensitive resistance changes in response to different temperatures. Moreover, by using the corresponding preparation methods, rGO can be easily combined with various substrates, which has led to it being extensively applied in the wearable field. This paper reviews the state-of-the-art advances in wearable temperature sensors based on rGO films and summarizes their sensing mechanisms, structure designs, functional material additions, manufacturing processes, and performances. Finally, the possible challenges and prospects of rGO-based wearable temperature sensors are briefly discussed. Full article

(This article belongs to the Special Issue Growth and Applications of Oxide Thin Films and Heterostructures)

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11 pages, 16037 KiB

Open AccessEditor’s ChoiceArticle

Human Bone-Marrow-Derived Stem-Cell-Seeded 3D Chitosan–Gelatin–Genipin Scaffolds Show Enhanced Extracellular Matrix Mineralization When Cultured under a Perfusion Flow in Osteogenic Medium

by Gabriele Boretti, Emanuele Giordano, Mariana Ionita, George Mihail Vlasceanu, Ólafur Eysteinn Sigurjónsson, Paolo Gargiulo and Joseph Lovecchio

Materials 2023, 16(17), 5898; https://doi.org/10.3390/ma16175898 - 29 Aug 2023

Cited by 3 | Viewed by 2100

Abstract

Tissue-engineered bone tissue grafts are a promising alternative to the more conventional use of natural donor bone grafts. However, choosing an appropriate biomaterial/scaffold to sustain cell survival, proliferation, and differentiation in a 3D environment remains one of the most critical issues in this [...] Read more.

Tissue-engineered bone tissue grafts are a promising alternative to the more conventional use of natural donor bone grafts. However, choosing an appropriate biomaterial/scaffold to sustain cell survival, proliferation, and differentiation in a 3D environment remains one of the most critical issues in this domain. Recently, chitosan/gelatin/genipin (CGG) hybrid scaffolds have been proven as a more suitable environment to induce osteogenic commitment in undifferentiated cells when doped with graphene oxide (GO). Some concern is, however, raised towards the use of graphene and graphene-related material in medical applications. The purpose of this work was thus to check if the osteogenic potential of CGG scaffolds without added GO could be increased by improving the medium diffusion in a 3D culture of differentiating cells. To this aim, the level of extracellular matrix (ECM) mineralization was evaluated in human bone-marrow-derived stem cell (hBMSC)-seeded 3D CGG scaffolds upon culture under a perfusion flow in a dedicated custom-made bioreactor system. One week after initiating dynamic culture, histological/histochemical evaluations of CGG scaffolds were carried out to analyze the early osteogenic commitment of the culture. The analyses show the enhanced ECM mineralization of the 3D perfused culture compared to the static counterpart. The results of this investigation reveal a new perspective on more efficient clinical applications of CGG scaffolds without added GO. Full article

(This article belongs to the Special Issue Synthetic and Biologic Materials for Prosthetic and Reconstructive Applications for Musculoskeletal Tissue)

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18 pages, 4178 KiB

Open AccessEditor’s ChoiceArticle

Photo- and Thermocatalytic CO₂ Methanation: A Comparison of Ni/Al₂O₃ and Ni–Ce Hydrotalcite-Derived Materials under UV and Visible Light

by Rafael Canales and Victoria Laura Barrio

Materials 2023, 16(17), 5907; https://doi.org/10.3390/ma16175907 - 29 Aug 2023

Cited by 2 | Viewed by 1486

Abstract

Catalysts derived from Ni/Al/Mg/Ce hydrotalcite were prepared via a co-precipitation method, varying the Ce/Al atomic ratio. All of the catalytic systems thus prepared were tested for CO₂ methanation under dark and photocatalytic conditions (visible and ultraviolet) under continuous flow with the light [...] Read more.

Catalysts derived from Ni/Al/Mg/Ce hydrotalcite were prepared via a co-precipitation method, varying the Ce/Al atomic ratio. All of the catalytic systems thus prepared were tested for CO₂ methanation under dark and photocatalytic conditions (visible and ultraviolet) under continuous flow with the light intensity set to 2.4 W cm⁻². The substitution of Al by Ce formed a solid solution, generating oxygen vacancies and Ce³⁺/Ce⁴⁺ ions that helped shift the dissociation of CO₂ towards the production of CH₄, thus enhancing the activity of methanation, especially at lower temperatures (<523 K) and with visible light at temperatures where other catalysts were inactive. Additionally, for comparison purposes, Ni/Al₂O₃-based catalysts prepared via wetness impregnation were synthesized with different Ni loadings. Analytical techniques were used for the characterization of the systems. The best results in terms of activity were as follows: Hydrotalcite with Ce promoter > Hydrotalcite without Ce promoter > 25Ni/Al₂O₃ > 13Ni/Al₂O₃. Hydrotalcite, with a Ce/Al atomic ratio of 0.22 and a Ni content of 23 wt%, produced 7.74 mmol CH₄ min⁻¹·g_cat at 473 K under visible light. Moreover, this catalyst exhibited stable photocatalytic activity during a 24 h reaction time with a CO₂ conversion rate of 65% and CH₄ selectivity of >98% at 523 K. This photocatalytic Sabatier enhancement achieved activity at lower temperatures than those reported in previous publications. Full article

(This article belongs to the Special Issue Advanced Materials for CO₂ Conversion)

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16 pages, 7674 KiB

Open AccessEditor’s ChoiceArticle

Two-Dimensional Microstructure-Based Model for Evaluating the Permeability Coefficient of Heterogeneous Construction Materials

by Jiaqi Chen, Shujun Yu, Wei Huang and Hao Wang

Materials 2023, 16(17), 5892; https://doi.org/10.3390/ma16175892 - 28 Aug 2023

Cited by 3 | Viewed by 1531

Abstract

The permeability coefficient of construction materials plays a crucial role in engineering quality and durability. In this study, a microstructure model based on real aggregate shape and digital image technology is proposed to predict the permeability coefficient of concrete. A two-dimensional, three-component finite [...] Read more.

The permeability coefficient of construction materials plays a crucial role in engineering quality and durability. In this study, a microstructure model based on real aggregate shape and digital image technology is proposed to predict the permeability coefficient of concrete. A two-dimensional, three-component finite element model of cement concrete was established considering the interfacial transition zone (ITZ) between aggregate and mortar. The permeability coefficient prediction model was developed by the finite element method. The accuracy of the model was verified by experimental data, and the influence of the water−cement ratio on the permeability coefficient of concrete was analyzed. The results show that this method has good prediction accuracy with a relative error of 1.73%. According to the verified model, the influences of aggregate content, aggregate characteristics, aggregate location, ITZ thickness, and other factors on the permeability of concrete were explored. The higher the water−cement ratio, the higher the permeability coefficient. With the increase in aggregate content, the permeability coefficient decreases. Aggregate permeability has a significant influence on the effective permeability coefficient of concrete within a certain range. The greater the roundness of aggregate, the greater the permeability of concrete. On the contrary, the larger aggregate size causes lower permeability. The permeability coefficient of concrete with segregation is lower than that with uniform distribution. At the same time, the permeability increases with the increase of ITZ thickness. Full article

(This article belongs to the Special Issue Experimental Tests and Numerical Analysis of Construction Materials)

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18 pages, 6806 KiB

Open AccessEditor’s ChoiceArticle

Determination of Thermal Properties of Mineral Wool Required for the Safety Analysis of Sandwich Panels Subjected to Fire Loads

by El Mehdi Ablaoui, Michał Malendowski, Wojciech Szymkuc and Zbigniew Pozorski

Materials 2023, 16(17), 5852; https://doi.org/10.3390/ma16175852 - 26 Aug 2023

Cited by 6 | Viewed by 2190

Abstract

The paper presents theoretical, experimental and numerical studies on the thermal behavior of mineral wool used in sandwich panels. The aim of this study is to investigate the thermal properties of mineral wool at elevated temperatures and provide a simple model that would [...] Read more.

The paper presents theoretical, experimental and numerical studies on the thermal behavior of mineral wool used in sandwich panels. The aim of this study is to investigate the thermal properties of mineral wool at elevated temperatures and provide a simple model that would allow us to determine the heat propagation in sandwich panels during a fire. The paper proposes a new method to experimentally evaluate thermal diffusivity, derived from theoretical premises. Experiments are conducted in a laboratory furnace where specimens are placed and temperatures inside specimens are measured. Different methods are used to process the test results and calculate the thermal diffusivity of mineral wool. Finally, a numerical analysis of heat transfer using the finite element method (FEM) is performed to validate the obtained thermal properties. Full article

(This article belongs to the Special Issue Experimental and Numerical Analysis of Sandwich Structures)

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16 pages, 3872 KiB

Open AccessEditor’s ChoiceArticle

Gold Nanoparticles-Functionalized Cotton as Promising Flexible and Green Substrate for Impedometric VOC Detection

by Silvia Casalinuovo, Daniela Caschera, Simone Quaranta, Virgilio Genova, Alessio Buzzin, Fulvio Federici, Giampiero de Cesare, Donatella Puglisi and Domenico Caputo

Materials 2023, 16(17), 5826; https://doi.org/10.3390/ma16175826 - 25 Aug 2023

Cited by 10 | Viewed by 1789

Abstract

This work focuses on the possible application of gold nanoparticles on flexible cotton fabric as acetone- and ethanol-sensitive substrates by means of impedance measurements. Specifically, citrate- and polyvinylpyrrolidone (PVP)-functionalized gold nanoparticles (Au NPs) were synthesized using green and well-established procedures and deposited on [...] Read more.

This work focuses on the possible application of gold nanoparticles on flexible cotton fabric as acetone- and ethanol-sensitive substrates by means of impedance measurements. Specifically, citrate- and polyvinylpyrrolidone (PVP)-functionalized gold nanoparticles (Au NPs) were synthesized using green and well-established procedures and deposited on cotton fabric. A complete structural and morphological characterization was conducted using UV–VIS and Fourier transform infrared (FT–IR) spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). A detailed dielectric characterization of the blank substrate revealed interfacial polarization effects related to both Au NPs and their specific surface functionalization. For instance, by entirely coating the cotton fabric (i.e., by creating a more insulating matrix), PVP was found to increase the sample resistance, i.e., to decrease the electrical interconnection of Au NPs with respect to citrate functionalized sample. However, it was observed that citrate functionalization provided a uniform distribution of Au NPs, which reduced their spacing and, therefore, facilitated electron transport. Regarding the detection of volatile organic compounds (VOCs), electrochemical impedance spectroscopy (EIS) measurements showed that hydrogen bonding and the resulting proton migration impedance are instrumental in distinguishing ethanol and acetone. Such findings can pave the way for the development of VOC sensors integrated into personal protective equipment and wearable telemedicine devices. This approach may be crucial for early disease diagnosis based on nanomaterials to attain low-cost/low-end and easy-to-use detectors of breath volatiles as disease markers. Full article

(This article belongs to the Special Issue Gold Nanoparticles: Synthesis, Properties, and Applications)

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11 pages, 1383 KiB

Open AccessEditor’s ChoiceArticle

Examining the Effect of Cu and Mn Dopants on the Structure of Zinc Blende ZnS Nanopowders

by Alexei Kuzmin, Inga Pudza, Milena Dile, Katrina Laganovska and Aleksejs Zolotarjovs

Materials 2023, 16(17), 5825; https://doi.org/10.3390/ma16175825 - 25 Aug 2023

Cited by 3 | Viewed by 2130

Abstract

It is known that doping zinc sulfide (ZnS) nanoparticles with Mn or Cu ions significantly affects their luminescent properties. Herein, we investigated how dopant atoms are incorporated into the structure of ZnS using X-ray diffraction and multi-edge X-ray absorption spectroscopy. The observed broadening [...] Read more.

It is known that doping zinc sulfide (ZnS) nanoparticles with Mn or Cu ions significantly affects their luminescent properties. Herein, we investigated how dopant atoms are incorporated into the structure of ZnS using X-ray diffraction and multi-edge X-ray absorption spectroscopy. The observed broadening of the X-ray diffraction patterns indicates an average crystallite size of about 6 nm. By analyzing the Zn, Mn, and Cu K-edge extended X-ray absorption fine structure (EXAFS) spectra using the reverse Monte Carlo method, we were able to determine the relaxations of the local environments around the dopants. Our findings suggested that upon the substitution of Zn by Mn or Cu ions, there is a shortening of the Cu–S bonds by 0.08 Å, whereas the Mn–S bonds exhibited lengthening by 0.07 Å. These experimental results were further confirmed by first-principles density functional theory calculations, which explained the increase in the Mn–S bond lengths due to the high-spin state of Mn

^{2 +}

ions. Full article

(This article belongs to the Special Issue Wide Bandgap Semiconductor Materials and Devices)

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17 pages, 2203 KiB

Open AccessEditor’s ChoiceArticle

The Application of Mott’s Distribution in the Fragmentation of Steel Coaxial Cylinders

by Octavian-Gabriel Chiriac, Florina Bucur, Adrian-Nicolae Rotariu and Eugen Trană

Materials 2023, 16(17), 5783; https://doi.org/10.3390/ma16175783 - 24 Aug 2023

Cited by 4 | Viewed by 1564

Abstract

This theoretical study analyzes the possibility to use the classical Mott’s hypothesis to model the natural fragmentation of cylindrical structures with two or more metal cylinders arranged coaxially. A critical analysis on the validity of the used hypothesis was conducted based on empirical [...] Read more.

This theoretical study analyzes the possibility to use the classical Mott’s hypothesis to model the natural fragmentation of cylindrical structures with two or more metal cylinders arranged coaxially. A critical analysis on the validity of the used hypothesis was conducted based on empirical relations and numerical simulations. The established algorithm allows the determination of a fragment mass scale parameter for each individual cylinder, which is why the cumulative distribution of fragments for the entire structure may be calculated. The results obtained for the structures with two and three cylinders, with equal masses or equal wall thicknesses, can be approximated using a modified Mott’s distribution formula in which the number of cylinders is used as an additional parameter. Full article

(This article belongs to the Special Issue Dynamic Mechanical Analysis of Energetic Materials)

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14 pages, 6636 KiB

Open AccessEditor’s ChoiceArticle

Properties of PBZTS Ferroelectric Ceramics Obtained Using Spark Plasma Sintering

by Dagmara Brzezińska, Dariusz Bochenek, Przemysław Niemiec and Grzegorz Dercz

Materials 2023, 16(17), 5756; https://doi.org/10.3390/ma16175756 - 23 Aug 2023

Cited by 2 | Viewed by 1336

Abstract

In this paper, spark plasma sintering was used to obtain and investigate (Pb_0.97Ba_0.03)(Zr_0.98Ti_0.02)_1−xSn_xO₃ (PBZTS) ceramic materials for x = 0, 0.02, 0.04, 0.06, and 0.08. Crystal structure, microstructure, dielectric [...] Read more.

In this paper, spark plasma sintering was used to obtain and investigate (Pb_0.97Ba_0.03)(Zr_0.98Ti_0.02)_1−xSn_xO₃ (PBZTS) ceramic materials for x = 0, 0.02, 0.04, 0.06, and 0.08. Crystal structure, microstructure, dielectric and ferroelectric properties, and electrical conductivity tests of a series of samples were carried out. The SPS sintering method ensures favorable dielectric and ferroelectric properties of PBZTS ceramic materials. X-ray studies have shown that the material has a perovskite structure. The samples have a densely packed material structure with properly crystallized grains. The fine-grained microstructure of the PZBZTS material with high grain homogeneity allows the application of higher electric fields. Ceramic samples obtained by the SPS method have higher density values than samples obtained by the classical method (FS). The permittivity at room temperature is in the range of 245–282, while at the phase transition temperature is in the range of 10,259–12,221. At room temperature, dielectric loss factor values range from 0.006 to 0.036. The hysteresis loops of PBZTS ceramics have a shape typical for ferroelectric hard materials, and the remnant polarization values range from 0.32 to 0.39 µC/cm². The activation energy E_a values of the PBZTS samples result mainly from the presence of oxygen vacancies. The PZT material doped with Ba and Sn and sintered via the SPS method has favorable physical parameters for applications in modern devices such as actuators or pulse capacitors. Full article

(This article belongs to the Special Issue Advances in Dielectric Ceramics)

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21 pages, 4927 KiB

Open AccessEditor’s ChoiceArticle

A Novel Nickel-Plated Carbon Fiber Insert in Aluminum Joints with Thermoplastic ABS Polymer or Stainless Steel

by Yoshitake Nishi, Kouhei Sagawa, Michael C. Faudree, Helmut Takahiro Uchida, Masae Kanda, Satoru Kaneko, Michelle Salvia, Yoshihito Matsumura and Hideki Kimura

Materials 2023, 16(17), 5777; https://doi.org/10.3390/ma16175777 - 23 Aug 2023

Cited by 1 | Viewed by 2036

Abstract

New types of hybrid aluminum joints: Al-acrylonitrile butadiene styrene (ABS) carbon fiber reinforced thermoplastic polymer (CFRTP) designated Al/Ni-CFP/ABS, and Al-18-8 Stainless steel, Al/Ni-CFP/18-8, by Ni-plated carbon fiber plug (Ni-CFP) insert not before seen in the literature have been fabricated. [...] Read more.

New types of hybrid aluminum joints: Al-acrylonitrile butadiene styrene (ABS) carbon fiber reinforced thermoplastic polymer (CFRTP) designated Al/Ni-CFP/ABS, and Al-18-8 Stainless steel, Al/Ni-CFP/18-8, by Ni-plated carbon fiber plug (Ni-CFP) insert not before seen in the literature have been fabricated. The goal is to take advantage of extremely high ~6 mm CF surface area for high adhesion, to enhance the safety level of aircraft and other parts. This is without fasteners, chemical treatment, or glue. First, the CFP is plated with Ni. Second, the higher melting point half-length is spot welded to the CFP; and third, the remaining half-length is fabricated. The ultimate tensile strength (UTS) of Al/Ni-CFP/ABS was raised 15 times over that of Al/ABS. Normalized ^cUTS according to CFP cross-section by Rule of Mixtures for ^cAl/Ni-CFP/18-8 was raised over that of ^cAl/Ni-CFP/18-8 from 140 to 360 MPa. Resistance energy to tensile deformation, U_T, was raised 12 times from Al/ABS to Al/Ni-CFP/ABS, and 6 times from Al/CFP/18-8 to Al/Ni-CFP/18-8. Spot welding allows rapid melting followed by rapid solidification for amorphous metal structures minimizing grain boundaries. The Ni-coating lowers or counters the effects of brittle Al₄C₃ and Fe_xC formation at the interface and prevents damage by impingement to CFs, allowing joints to take on more of the load. Full article

(This article belongs to the Special Issue New Advances in Aluminum Alloys and Composites for Lightweight Applications)

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25 pages, 8948 KiB

Open AccessEditor’s ChoiceArticle

Dynamic Characteristics and Effective Stiffness Properties of Sandwich Panels with Hierarchical Hexagonal Honeycomb

by Zixuan Bai, Cheng Chen, Xinlong Yang, Yifeng Zhong and Rong Liu

Materials 2023, 16(17), 5741; https://doi.org/10.3390/ma16175741 - 22 Aug 2023

Cited by 3 | Viewed by 1667

Abstract

The dynamic characteristics of sandwich panels with a hierarchical hexagonal honeycomb (SP-HHHs) show significant improvements due to their distinct hierarchy configurations. However, this also increases the complexity of structural analysis. To address this issue, the variational asymptotic method was utilized to homogenize the [...] Read more.

The dynamic characteristics of sandwich panels with a hierarchical hexagonal honeycomb (SP-HHHs) show significant improvements due to their distinct hierarchy configurations. However, this also increases the complexity of structural analysis. To address this issue, the variational asymptotic method was utilized to homogenize the unit cell of the SP-HHH and obtain the equivalent stiffness, establishing a two-dimensional equivalent plate model (2D-EPM). The accuracy and effectiveness of the 2D-EPM were then verified through comparisons with the results from a detailed 3D FE model in terms of the free vibration and frequency- and time-domain forced vibration, as well as through local field recovery analysis at peak and trough times. Furthermore, the tailorability of the typical unit cell was utilized to perform a parametric analysis of the effects of the length and thickness ratios of the first-order hierarchy on the dynamic characteristics of the SP-HHH under periodic loading. The results reveal that the vertices serve as weak points in the SP-HHH, while the vertex cell pattern significantly influences the specific stiffness and stiffness characteristics of the panel. The SP-HHH with hexagonal vertex cells has superior specific stiffness compared to panels with circular and rectangular vertex cells, resulting in a more lightweight design and enhanced stiffness. Full article

(This article belongs to the Special Issue Lightweight and High-Strength Sandwich Panel)

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37 pages, 21017 KiB

Open AccessEditor’s ChoiceArticle

Milling Mechanism and Chattering Stability of Nickel-Based Superalloy Inconel 718

by Jin Zheng, Yaoman Zhang and Hanying Qiao

Materials 2023, 16(17), 5748; https://doi.org/10.3390/ma16175748 - 22 Aug 2023

Cited by 9 | Viewed by 2046

Abstract

Nickel-based superalloy Inconel 718 is widely used in the aerospace industry for its excellent high-temperature strength and thermal stability. However, milling Inconel 718 presents challenges because of the significantly increased cutting force and vibration, since Inconel 718 is a typical difficult-to-machine material. This [...] Read more.

Nickel-based superalloy Inconel 718 is widely used in the aerospace industry for its excellent high-temperature strength and thermal stability. However, milling Inconel 718 presents challenges because of the significantly increased cutting force and vibration, since Inconel 718 is a typical difficult-to-machine material. This paper takes the milling process of Inconel 718 as the research object, initially, and a milling force model of Inconel 718 is established. Subsequently, the finite element analysis method is used to analyze the stress field, temperature field, and milling force in the milling process of Inconel 718. Building upon this, a dynamic equation of the milling of Inconel 718 is established, and based on the modal experiment, stability lobe diagrams are drawn. Furthermore, milling experiments on Inconel 718 are designed, and the results calculated using the milling force model and finite element analysis are verified through comparison to the experimental results; then, the fmincon optimization algorithm is used to optimize the processing parameters of Inconel 718. Eventually, the results of the multi-objective optimization illustrate that the best processing parameters are a spindle speed of 3199.2 rpm and a feed speed of 80 mm/min with an axial depth of cut of 0.25 mm. Based on this, the best machining parameters are determined, which point towards an improvement of the machining efficiency and quality of Inconel 718. Full article

(This article belongs to the Section Metals and Alloys)

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18 pages, 3901 KiB

Open AccessEditor’s ChoiceArticle

Study on the Dye Removal from Aqueous Solutions by Graphene-Based Adsorbents

by Paunka Vassileva, Vencislav Tumbalev, Diana Kichukova, Dimitrinka Voykova, Daniela Kovacheva and Ivanka Spassova

Materials 2023, 16(17), 5754; https://doi.org/10.3390/ma16175754 - 22 Aug 2023

Cited by 13 | Viewed by 1922

Abstract

In the current investigation, the removal efficiency regarding a cationic dye, methylene blue (MB), from three graphene-based materials was investigated. The materials’ characterization process involved instrumental methods such as XRD, XPS, SEM, TEM, FTIR, and nitrogen adsorption at 77 K. The survey examined [...] Read more.

In the current investigation, the removal efficiency regarding a cationic dye, methylene blue (MB), from three graphene-based materials was investigated. The materials’ characterization process involved instrumental methods such as XRD, XPS, SEM, TEM, FTIR, and nitrogen adsorption at 77 K. The survey examined how various process factors influenced the ability of the studied materials to adsorb cationic dyes. These parameters encompassed contact time, initial dye concentrations, solution pH, and temperature. The adsorption procedure was effectively explained through the application of pseudo-second-order and Langmuir models. The maximum adsorption capacity for the best adsorbent at 293 K was found to be 49.4 mg g⁻¹. In addition, the study also determined the entropy, enthalpy, and Gibbs free energy values associated with the removal of MB and showed that the adsorption of MB is endothermic, feasible, and spontaneous. The results also revealed that the studied materials are suitable adsorbents for the removal of cationic dyes. Full article

(This article belongs to the Special Issue Size-Dependent Effects in Materials for Environmental Protection and Energy Application)

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13 pages, 8068 KiB

Open AccessEditor’s ChoiceArticle

Effect of Tempering Temperature on Hydrogen Embrittlement of SCM440 Tempered Martensitic Steel

by Sang-Gyu Kim, Jae-Yun Kim and Byoungchul Hwang

Materials 2023, 16(16), 5709; https://doi.org/10.3390/ma16165709 - 21 Aug 2023

Cited by 6 | Viewed by 2813

Abstract

The effect of tempering temperature on the hydrogen embrittlement characteristics of SCM440 tempered martensitic steels was investigated in terms of their microstructure and hydrogen desorption behavior. The microstructures were characterized using scanning and transmission electron microscopy, as well as X-ray diffraction and electron [...] Read more.

The effect of tempering temperature on the hydrogen embrittlement characteristics of SCM440 tempered martensitic steels was investigated in terms of their microstructure and hydrogen desorption behavior. The microstructures were characterized using scanning and transmission electron microscopy, as well as X-ray diffraction and electron backscattered diffraction analysis. Thermal desorption analysis (TDA) was performed to examine the amount and trapping behavior of hydrogen. The cementite morphology of the SCM440 tempered martensitic steels gradually changed from a long lamellar shape to a segmented short-rod shape with an increasing tempering temperature. A slow strain rate tensile test was conducted after electrochemical hydrogen charging to evaluate the hydrogen embrittlement resistance. The hydrogen embrittlement resistance of the SCM440 tempered martensitic steels increased with an increasing tempering temperature because of the decrease in the fraction of the low-angle grain boundaries and dislocation density. The low-angle grain boundaries and dislocations, which acted as reversible hydrogen trap sites, were critical factors in determining the hydrogen embrittlement resistance, and this was supported by the decreased diffusible hydrogen content as measured by TDA. Fine carbides formed in the steel tempered at a relatively higher temperature acted as irreversible hydrogen trap sites and contributed to improving the hydrogen embrittlement resistance. Our findings can suggest that the tempering temperature of SCM440 tempered martensitic steel plays an important role in determining its hydrogen embrittlement resistance. Full article

(This article belongs to the Section Metals and Alloys)

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18 pages, 3483 KiB

Open AccessEditor’s ChoiceArticle

Application of Anodic Titanium Oxide Modified with Silver Nanoparticles as a Substrate for Surface-Enhanced Raman Spectroscopy

by Mateusz Czerwiński, Ruben del Olmo Martinez and Marta Michalska-Domańska

Materials 2023, 16(16), 5696; https://doi.org/10.3390/ma16165696 - 19 Aug 2023

Cited by 1 | Viewed by 1602

Abstract

The formation of nanostructured anodic titanium oxide (ATO) layers was explored on pure titanium by conventional anodizing under two different operating conditions to form nanotube and nanopore morphologies. The ATO layers were successfully developed and showed optimal structural integrity after the annealing process [...] Read more.

The formation of nanostructured anodic titanium oxide (ATO) layers was explored on pure titanium by conventional anodizing under two different operating conditions to form nanotube and nanopore morphologies. The ATO layers were successfully developed and showed optimal structural integrity after the annealing process conducted in the air atmosphere at 450 °C. The ATO nanopore film was thinner (1.2 +/− 0.3 μm) than the ATO nanotube layer (3.3 +/− 0.6 μm). Differences in internal pore diameter were also noticeable, i.e., 88 +/− 9 nm and 64 +/− 7 nm for ATO nanopore and nanotube morphology, respectively. The silver deposition on ATO was successfully carried out on both ATO morphologies by silver electrodeposition and Ag colloid deposition. The most homogeneous silver deposit was prepared by Ag electrodeposition on the ATO nanopores. Therefore, these samples were selected as potential surface-enhanced Raman spectroscopy (SERS) substrate, and evaluation using pyridine (aq.) as a testing analyte was conducted. The results revealed that the most intense SERS signal was registered for nanopore ATO/Ag substrate obtained by electrodeposition of silver on ATO by 2.5 min at 1 V from 0.05M AgNO₃ (aq.) (analytical enhancement factor, AEF ~5.3 × 10⁴) and 0.025 M AgNO₃ (aq.) (AEF ~2.7 × 10²). The current findings reveal a low-complexity and inexpensive synthesis of efficient SERS substrates, which allows modification of the substrate morphology by selecting the parameters of the synthesis process. Full article

(This article belongs to the Section Advanced Nanomaterials and Nanotechnology)

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27 pages, 7456 KiB

Open AccessEditor’s ChoiceArticle

New Experimental Evidence for Drying Shrinkage of Alkali-Activated Slag with Sodium Hydroxide

by Marco Sirotti, Brice Delsaute and Stéphanie Staquet

Materials 2023, 16(16), 5659; https://doi.org/10.3390/ma16165659 - 17 Aug 2023

Cited by 5 | Viewed by 1501

Abstract

Alkali-activated slag (AAS) is emerging as a possible and more sustainable alternative to Ordinary Portland Cement (OPC) in the construction industry, thanks to its good mechanical and chemical properties. Conversely, the effects of its high drying shrinkage are still a concern for its [...] Read more.

Alkali-activated slag (AAS) is emerging as a possible and more sustainable alternative to Ordinary Portland Cement (OPC) in the construction industry, thanks to its good mechanical and chemical properties. Conversely, the effects of its high drying shrinkage are still a concern for its long-term durability. This study aims to investigate the drying shrinkage behaviour of six AAS/sodium hydroxide mortar compositions and the main phenomena affecting their drying shrinkage behaviour. Specifically, the molarity, solution-to-binder ratio (s/b), autogenous shrinkage, creep compliance, microcracking, and carbonation are considered as possible causes of the differences between AAS and OPC. The results show that it is not possible to correlate the shrinkage magnitude with the molarity of the activating solution, while an increase in the s/b increases the drying shrinkage. Concerning the other factors, autogenous deformation remains significant even after a period of 112 days, while the creep compliance is definitely affected by the drying process but does not seem to affect the shrinkage magnitude. Furthermore, the presence of microcracks caused by the drying process definitely influences the drying shrinkage. Finally, carbonation depends on the molarity of the activating solution, even though its effects on the material are still unclear. Full article

(This article belongs to the Special Issue Research on Alkali-Activated Materials)

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10 pages, 2282 KiB

Open AccessEditor’s ChoiceArticle

Al₂O₃ Layers Grown by Atomic Layer Deposition as Gate Insulator in 3C-SiC MOS Devices

by Emanuela Schilirò, Patrick Fiorenza, Raffaella Lo Nigro, Bruno Galizia, Giuseppe Greco, Salvatore Di Franco, Corrado Bongiorno, Francesco La Via, Filippo Giannazzo and Fabrizio Roccaforte

Materials 2023, 16(16), 5638; https://doi.org/10.3390/ma16165638 - 15 Aug 2023

Cited by 7 | Viewed by 2684

Abstract

Metal-oxide-semiconductor (MOS) capacitors with Al₂O₃ as a gate insulator are fabricated on cubic silicon carbide (3C-SiC). Al₂O₃ is deposited both by thermal and plasma-enhanced Atomic Layer Deposition (ALD) on a thermally grown 5 nm SiO₂ interlayer [...] Read more.

Metal-oxide-semiconductor (MOS) capacitors with Al₂O₃ as a gate insulator are fabricated on cubic silicon carbide (3C-SiC). Al₂O₃ is deposited both by thermal and plasma-enhanced Atomic Layer Deposition (ALD) on a thermally grown 5 nm SiO₂ interlayer to improve the ALD nucleation and guarantee a better band offset with the SiC. The deposited Al₂O₃/SiO₂ stacks show lower negative shifts of the flat band voltage V_FB (in the range of about −3 V) compared with the conventional single SiO₂ layer (in the range of −9 V). This lower negative shift is due to the combined effect of the Al₂O₃ higher permittivity (ε = 8) and to the reduced amount of carbon defects generated during the short thermal oxidation process for the thin SiO₂. Moreover, the comparison between thermal and plasma-enhanced ALD suggests that this latter approach produces Al₂O₃ layers possessing better insulating behavior in terms of distribution of the leakage current breakdown. In fact, despite both possessing a breakdown voltage of 26 V, the T-ALD Al₂O₃ sample is characterised by a higher current density starting from 15 V. This can be attributable to the slightly inferior quality (in terms of density and defects) of Al₂O₃ obtained by the thermal approach and, which also explains its non-uniform dC/dV distribution arising by SCM maps. Full article

(This article belongs to the Special Issue Silicon Carbide: Material Growth, Device Processing and Applications)

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13 pages, 5163 KiB

Open AccessEditor’s ChoiceArticle

Controlling the Cooling Rate of Hydrothermal Synthesis to Enhance the Supercapacitive Properties of β-Nickel Hydroxide Electrode Materials

by Yang-Ming Lu and Sheng-Huai Hong

Materials 2023, 16(16), 5576; https://doi.org/10.3390/ma16165576 - 11 Aug 2023

Cited by 3 | Viewed by 1475

Abstract

The demand for power storage devices with good quality, fast charging and high energy density is becoming more and more urgent in today’s electronic technology. For batteries and traditional capacitors, it is an insurmountable challenge to combine fast charging and discharging, large capacitance [...] Read more.

The demand for power storage devices with good quality, fast charging and high energy density is becoming more and more urgent in today’s electronic technology. For batteries and traditional capacitors, it is an insurmountable challenge to combine fast charging and discharging, large capacitance and long-life properties. The characteristics of supercapacitors can meet all the above requirements at the same time. In this study, a simple one-step hydrothermal method was successfully used to grow β-nickel hydroxide nanocone particles directly on the 3D foamed nickel substrate as a working electrode material for supercapacitors. After growing β-nickel hydroxide crystals on 3D foamed nickel substrate, by controlling the cooling rate, a well-crystalized β-nickel hydroxide with good capacitance characteristics can be obtained. Cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS) were used to analyze the capacitance characteristics of the β-nickel hydroxide electrode. The research results show that the specific capacitance value of the β-Ni(OH)₂/3D nickel foam electrode material prepared at the cooling rate of 10 °C/h can reach 539 F/g with the charge–discharge test at a current density of 3 A/g. After 1000 continuous charge and discharge cycles, the material still retains 94.1% of the specific capacitance value. Full article

(This article belongs to the Special Issue Electrochemical Material Science and Electrode Processes)

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15 pages, 2858 KiB

Open AccessEditor’s ChoiceReview

Bio-Based Binder Development for Lithium-Ion Batteries

by Illia Dobryden, Céline Montanari, Dhrubajyoti Bhattacharjya, Juhanes Aydin and Anwar Ahniyaz

Materials 2023, 16(16), 5553; https://doi.org/10.3390/ma16165553 - 10 Aug 2023

Cited by 17 | Viewed by 6191

Abstract

The development of rechargeable lithium-ion battery (LIB) technology has facilitated the shift toward electric vehicles and grid storage solutions. This technology is currently undergoing significant development to meet industrial applications for portable electronics and provide our society with “greener” electricity. The large increase [...] Read more.

The development of rechargeable lithium-ion battery (LIB) technology has facilitated the shift toward electric vehicles and grid storage solutions. This technology is currently undergoing significant development to meet industrial applications for portable electronics and provide our society with “greener” electricity. The large increase in LIB production following the growing demand from the automotive sector has led to the establishment of gigafactories worldwide, thus increasing the substantial consumption of fossil-based and non-sustainable materials, such as polyvinylidene fluoride and/or styrene-butadiene rubber as binders in cathode and anode formulations. Furthermore, the use of raw resources, such as Li, Ni, and Mn in cathode active materials and graphite and nanosilicon in anodes, necessitates further efforts to enhance battery efficiency. To foster a global sustainable transition in LIB manufacturing and reduce reliance on non-sustainable materials, the implementation of bio-based binder solutions for electrodes in LIBs is crucial. Bio-based binders such as cellulose, lignin, alginate, gums, starch, and others can address environmental concerns and can enhance LIBs’ performance. This review aims to provide an overview of the current progress in the development and application of bio-based binders for LIB electrode manufacturing, highlighting their significance toward sustainable development. Full article

(This article belongs to the Special Issue Surface/Interface Science of Advanced Energy Conversion and Storage Materials)

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14 pages, 5451 KiB

Open AccessEditor’s ChoiceArticle

Effect of High-Speed Sintering on the Optical Properties, Microstructure, and Phase Distribution of Multilayered Zirconia Stabilized with 5 mol% Yttria

by Mi-Hyang Cho and Hyo-Joung Seol

Materials 2023, 16(16), 5570; https://doi.org/10.3390/ma16165570 - 10 Aug 2023

Cited by 9 | Viewed by 2129

Abstract

As dental 5 mol% yttria-stabilized (5Y-) zirconia demand high esthetics, it is necessary to clarify how the optical properties are affected by high-speed sintering, which is not yet fully understood. Our study aimed to investigate the effect of high-speed sintering on the translucency [...] Read more.

As dental 5 mol% yttria-stabilized (5Y-) zirconia demand high esthetics, it is necessary to clarify how the optical properties are affected by high-speed sintering, which is not yet fully understood. Our study aimed to investigate the effect of high-speed sintering on the translucency and opalescence parameters (TP and OP, respectively), as well as their related microstructure and phase distribution, using two types of multilayered 5Y-zirconia. Multilayered 5Y-zirconia (Cercon xt ML, Lava Esthetic) were cut layer-by-layer, followed by conventional and high-speed sintering. The TP and OP values were subsequently obtained using a spectrophotometer, and field emission scanning electron microscopy images were used to analyze the average grain size. The phase fractions were analyzed using X-ray diffraction. Regardless of the zirconia type, the TP was slightly lowered by high-speed sintering in all the layers except the dentin layer (DL) for Lava Esthetic (p < 0.05). The OP decreased by high-speed sintering in the DL for Cercon xt ML and in all the layers for Lava Esthetic (p < 0.05). The decrease in translucency after high-speed sintering was attributed to a decrease in the yttria-rich t’-phase with low tetragonality, along with an increase in the yttria-lean t-phase with high tetragonality. Full article

(This article belongs to the Special Issue Advanced Materials for Dental Prosthesis: Current Advances and Future Trends)

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12 pages, 3093 KiB

Open AccessEditor’s ChoiceArticle

Mono- and Co-Doped Mn-Doped CsPbCl₃ Perovskites with Enhanced Doping Efficiency and Photoluminescent Performance

by Hao Jiang, Yiting Zhao, Fangchao Liu, Yongqi Yan, Yinuo Ma, Hexin Bao, Zhongchen Wu, Wei-Yan Cong and Ying-Bo Lu

Materials 2023, 16(16), 5545; https://doi.org/10.3390/ma16165545 - 9 Aug 2023

Cited by 4 | Viewed by 2778

Abstract

To investigate the effect of Mn and other metal dopants on the photoelectronic performance of CsPbCl₃ perovskites, we conducted a series of theoretical analyses. Our findings showed that after Mn mono-doping, the CsPbCl₃ lattice contracted and the bonding strength increased, resulting [...] Read more.

To investigate the effect of Mn and other metal dopants on the photoelectronic performance of CsPbCl₃ perovskites, we conducted a series of theoretical analyses. Our findings showed that after Mn mono-doping, the CsPbCl₃ lattice contracted and the bonding strength increased, resulting in a more compact structure of the metal octahedral cage. The relaxation of the metal octahedral cage, along with the Jahn–Teller effect, results in a decrease in lattice strain between the octahedra and a reduction in the energy of the entire lattice due to the deformation of the metal octahedron. These three factors work together to reduce intrinsic defects and enhance the stability and electronic properties of CsPbCl₃ perovskites. The solubility of the Mn dopant is significantly increased when co-doped with Ni, Fe, and Co dopants, as it compensates for the lattice strain induced by Mn. Doping CsPbCl₃ perovskites reduces the band gap due to the decreased contributions of 3d orbitals from the dopants. Our analyses have revealed that strengthening the CsPbCl₃ lattice and reducing intrinsic defects can result in improved stability and PL properties. Moreover, increasing Mn solubility and decreasing the bandgap can enhance the PLQY of orange luminescence in CsPbCl₃ perovskites. These findings offer valuable insights for the development of effective strategies to enhance the photoelectronic properties of these materials. Full article

(This article belongs to the Section Materials Physics)

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17 pages, 3590 KiB

Open AccessEditor’s ChoiceReview

Optimization of Spark Plasma Sintering Technology by Taguchi Method in the Production of a Wide Range of Materials: Review

by Robert Kruzel, Tomasz Dembiczak and Joanna Wachowicz

Materials 2023, 16(16), 5539; https://doi.org/10.3390/ma16165539 - 9 Aug 2023

Cited by 9 | Viewed by 2569

Abstract

This paper reviews the production of sinters using the spark plasma sintering method. SPS (spark plasma sintering) technology has been used for several decades, mainly in laboratories, to consolidate a huge number of both new and traditional materials. However, it is now more [...] Read more.

This paper reviews the production of sinters using the spark plasma sintering method. SPS (spark plasma sintering) technology has been used for several decades, mainly in laboratories, to consolidate a huge number of both new and traditional materials. However, it is now more often introduced into practical industrial use, with equipment as early as the fifth generation capable of producing larger-size components at competitive costs. Although the mechanism of sintering with the use of this method is not yet understood, the effectiveness of the SPS process for the rapid and efficient consolidation of a wide range of materials with novel micro-structures remains indisputable. With a relatively wide variation in chemical composition, the structure allows the selection of appropriate consolidation parameters for these materials. The influence on the values of apparent density and mechanical properties depends on the parameters of the spark plasma sintering process. In order to achieve a density close to the theoretical density of sinters, optimization of the sintering parameters, i.e., sintering temperature, heating rate, sintering time, pressing pressure and protective atmosphere, should be carried out. In this paper, the optimization of spark plasma sintering of Si₃N₄–Al₂O₃–ZrO₂ composite was carried out using the Taguchi method. The effects of four sintering factors, namely heating rate, sintering time, sintering temperature and sintering pressure, on the final density were investigated. Optimal sintering conditions were proposed and a confirmation experiment was conducted. The optimal combination of sintering conditions for spark plasma sintering (SPS) of Si₃N₄–Al₂O₃–ZrO₂ composite for high apparent density was determined as A3-B3-C3-D2. Based on ANOVA analysis, it was found that the apparent density of sintering was significantly influenced by sintering temperature, followed by pressing pressure, sintering time and heating rate. Validation of the developed mathematical model predicting the apparent density of sinters showed close agreement between the predicted response results and experimental results. Full article

(This article belongs to the Special Issue Advanced Powder Metallurgy Materials and Technology)

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25 pages, 7104 KiB

Open AccessEditor’s ChoiceReview

Cyclodextrins for Lithium Batteries Applications

by Mohamed M. H. Desoky, Fabrizio Caldera, Valentina Brunella, Riccardo Ferrero, Gjylije Hoti and Francesco Trotta

Materials 2023, 16(16), 5540; https://doi.org/10.3390/ma16165540 - 9 Aug 2023

Cited by 10 | Viewed by 3386

Abstract

Due to their high energy and power density, lithium-ion batteries (LIBs) have gained popularity in response to the demand for effective energy storage solutions. The importance of the electrode architecture in determining battery performance highlights the demand for optimization. By developing useful organic [...] Read more.

Due to their high energy and power density, lithium-ion batteries (LIBs) have gained popularity in response to the demand for effective energy storage solutions. The importance of the electrode architecture in determining battery performance highlights the demand for optimization. By developing useful organic polymers, cyclodextrin architectures have been investigated to improve the performance of Li-based batteries. The macrocyclic oligosaccharides known as cyclodextrins (CDs) have relatively hydrophobic cavities that can enclose other molecules. There are many industries where this “host–guest” relationship has been found useful. The hydrogen bonding and suitable inner cavity diameter of CD have led to its selection as a lithium-ion diffusion channel. CDs have also been used as solid electrolytes for solid-state batteries and as separators and binders to ensure adhesion between electrode components. This review gives a general overview of CD-based materials and how they are used in battery components, highlighting their advantages. Full article

(This article belongs to the Special Issue Cyclodextrins: Aged Materials for New Applications)

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18 pages, 16569 KiB

Open AccessEditor’s ChoiceArticle

Origin and Evolution of Cracks in the Glaze Surface of a Ceramic during the Cooling Process

by Tiantian Chen, Bin Gong and Chun’an Tang

Materials 2023, 16(16), 5508; https://doi.org/10.3390/ma16165508 - 8 Aug 2023

Cited by 5 | Viewed by 2426

Abstract

Because of the significant difference between the thermal expansion coefficients of ceramic blank and glaze, the glaze typically undergoes more pronounced shrinkage than the blank during ceramic cooling, which results in high stress concentrations and cracking. In this study, the mechanical mechanism of [...] Read more.

Because of the significant difference between the thermal expansion coefficients of ceramic blank and glaze, the glaze typically undergoes more pronounced shrinkage than the blank during ceramic cooling, which results in high stress concentrations and cracking. In this study, the mechanical mechanism of glaze cracking is studied, based on the statistical strength theory, damage mechanics, and continuum mechanics. Furthermore, the influence of the glaze layer thickness, heat transfer coefficient, expansion coefficient, and temperature difference on the creation and propagation of inner microcracks is systematically investigated, and the final discrete fracture network of ceramics is discussed at the specific crack saturation state. The results show that (1) a higher heat transfer coefficient will lead to a more uniform distribution of the surface temperature and a faster cooling process of the ceramics, reducing the number of microcracks when the ambient temperature is reached; (2) the thinner glaze layer is less prone to cracking when its thickness is smaller than that of the blank. However, when the thickness of the glaze layer is similar to that of the blank, the increased thickness of the glaze layer will increase the number of cracks on its surface; and (3) when the expansion coefficient of the glaze layer is smaller than that of the blank, cracks will not occur inside the glaze layer. However, as the coefficient of the thermal expansion of the glaze layer continuously rises, the number of cracks on its surface will first increase and then decrease. Full article

(This article belongs to the Special Issue Damage, Fracture and Fatigue of Ceramic Matrix Composites (CMCs))

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28 pages, 6109 KiB

Open AccessEditor’s ChoiceArticle

Properties of Self-Compacting Concrete Produced with Optimized Volumes of Calcined Clay and Rice Husk Ash—Emphasis on Rheology, Flowability Retention and Durability

by Abubakar Muhammad and Karl-Christian Thienel

Materials 2023, 16(16), 5513; https://doi.org/10.3390/ma16165513 - 8 Aug 2023

Cited by 10 | Viewed by 2242

Abstract

The durability of concrete requires a dense microstructure which can be achieved by using self-compacting concrete (SCC). Both calcined clay (CC) and rice husk ash (RHA) are promising supplementary cementitious materials (SCMs) that can partially replace cement, but their use in SCC is [...] Read more.

The durability of concrete requires a dense microstructure which can be achieved by using self-compacting concrete (SCC). Both calcined clay (CC) and rice husk ash (RHA) are promising supplementary cementitious materials (SCMs) that can partially replace cement, but their use in SCC is critical due to their higher water demand (WD) and specific surface area (SSA) compared to cement. The effect of partial substitution of cement at 20 vol-% with binary and ternary blends of CC and RHA on flowability retention and durability of SCC was investigated. The empirical method of SCC design was adopted considering the physical properties of both CC and RHA. The deformability of the SCC was evaluated using the slump flow and J-ring tests. The T₅₀₀ time and the V-funnel test were used to assess the viscosity of the SCC. The flowability retention was monitored by the plunger method, and flow resistance was determined based on the rheological measurements of SCC. The evolution of the hydrate phases of the binder in SCC was determined by thermogravimetric analysis, while the durability was evaluated by a rapid chloride migration test. Cement partial replacement with 20 vol-% CC has no significant effect on fresh SCC, flowability retention, compressive strength and durability properties. On the other hand, 20 vol-% RHA requires a higher dosage of SP to achieve self-compactability and increase the viscosity of SCC. Its flowability retention is only up to 30 min after mixing and exhibited higher flow resistance. It consumes more calcium hydroxide (CH) and improves the compressive strength and chloride resistance of SCC. The ternary blending with CC and RHA yielded better fresh SCC properties compared to the binary blend with RHA, while an improved chloride penetration resistance could be achieved compared to the binary CC blend. Full article

(This article belongs to the Special Issue The 15th Anniversary of Materials—Recent Advances in Construction and Building Materials)

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13 pages, 4252 KiB

Open AccessEditor’s ChoiceArticle

Microstructure of TiAl Capsules Processed by Electron Beam Powder Bed Fusion Followed by Post-Hot Isostatic Pressing

by Hanieh Bakhshi Farkoush, Giulio Marchese, Emilio Bassini, Alberta Aversa and Sara Biamino

Materials 2023, 16(16), 5510; https://doi.org/10.3390/ma16165510 - 8 Aug 2023

Cited by 2 | Viewed by 1612

Abstract

The microstructures of intermetallic γ-titanium aluminide (TiAl) alloys are subjected to a certain degree of Al evaporation when processed by electron beam powder bed fusion (EB-PBF). The magnitude of the Al-loss is mainly correlated with the process parameters, and highly energetic parameters produce [...] Read more.

The microstructures of intermetallic γ-titanium aluminide (TiAl) alloys are subjected to a certain degree of Al evaporation when processed by electron beam powder bed fusion (EB-PBF). The magnitude of the Al-loss is mainly correlated with the process parameters, and highly energetic parameters produce significant Al evaporation. The Al-loss leads to different microstructures, including the formation of inhomogeneous banded structures, thus negatively affecting its mechanical performance. For this reason, the current work deals with creating EB-PBFed TiAl capsules with the inner part produced using only the pre-heating step and melting parameters with low energetic parameters applying high beam speed from 5000 to 3000 mm/s. This approach is investigated to reduce the Al-loss and microstructure inhomogeneity after hot isostatic pressing (HIP). The results showed that the HIP treatment effectively densified the capsules obtaining a relative density of around 100%. After HIP, the capsules produced with the inner part melted at 3000 mm/s presented a lower area shrinkage (around 6.6%) compared to the capsules produced using only the pre-heating step in the core part (around 20.7%). The different magnitudes of shrinkage derived from different levels of residual porosity consolidated during the HIP process. The HIPed capsules exhibited the presence of previous particle boundaries (PPBs), covered by α₂ phases. Notably, applying low energetic parameters to melt the core partially eliminates the particles’ surface, thus reducing the PPBs formation. In this case, the capsules melted with low energetic parameters (3000 mm/s) exhibited α₂ concentration of 3.5% and an average size of 13 µm compared to the capsules produced with the pre-heating step in the inner part with an α₂ around 5.7% and an average size around 23 µm. Moreover, the Al-loss of the capsules was drastically limited, as determined by X-ray fluorescence (XRF) analysis. More in detail, the capsules produced with the pre-heating step reported an atomic percentage of Al of 48.75, while using low energetic melting parameters led to 48.36. This result was interesting, considering that the massive samples produced with standard parameters (so more energetic ones) revealed atomic Al percentage from 48.04 to 47.70. Finally, the recycled small particles showed a higher fraction of α₂ phases with respect to the coarse particles, as determined by X-ray diffraction (XRD). Full article

(This article belongs to the Special Issue Recent Application of Powder Metallurgy Materials)

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18 pages, 4641 KiB

Open AccessEditor’s ChoiceArticle

Cetuximab-Conjugated Magnetic Poly(Lactic-co-Glycolic Acid) Nanoparticles for Dual-Targeted Delivery of Irinotecan in Glioma Treatment

by Banendu Sunder Dash, Yu-Jen Lu, Shu-Hui Luo and Jyh-Ping Chen

Materials 2023, 16(16), 5526; https://doi.org/10.3390/ma16165526 - 8 Aug 2023

Cited by 5 | Viewed by 2362

Abstract

A glioma is the most common malignant primary brain tumor in adults and is categorized according to its growth potential and aggressiveness. Within gliomas, grade 4 glioblastoma remains one of the most lethal malignant solid tumors, with a median survival time less than [...] Read more.

A glioma is the most common malignant primary brain tumor in adults and is categorized according to its growth potential and aggressiveness. Within gliomas, grade 4 glioblastoma remains one of the most lethal malignant solid tumors, with a median survival time less than 18 months. By encapsulating CPT-11 and oleic acid-coated magnetic nanoparticles (OMNPs) in poly(lactic-co-glycolic acid) (PLGA) nanoparticles, we first prepared PLGA@OMNP@CPT-11 nanoparticles in this study. After conjugating cetuximab (CET) with PLGA@OMNP@CPT-11, spherical PLGA@OMNP@CPT-11-CET nanoparticles with 250 nm diameter, 33% drug encapsulation efficiency, and 22% drug loading efficiency were prepared in a single emulsion/evaporation step. The nanoparticles were used for dual-targeted delivery of CPT-11 to U87 primary glioblastoma cells by actively targeting the overexpressed epidermal growth factor receptor on the surface of U87 cells, as well as by magnetic targeting. The physicochemical properties of nanoparticles were characterized in detail. CET-mediated targeting promotes intracellular uptake of nanoparticles by U87 cells, which can release four times more drug at pH 5 than at pH 7.4 to facilitate drug release in endosomes after intracellular uptake. The nanovehicle PLGA@OMNP-CET is cytocompatible and hemocompatible. After loading CPT-11, PLGA@OMNP@CPT-11-CET shows the highest cytotoxicity toward U87 compared with free CPT-11 and PLGA@OMNP@CPT-11 by providing the lowest drug concentration for half-maximal cell death (IC₅₀) and the highest rate of cell apoptosis. In orthotopic brain tumor-bearing nude mice with U87 xenografts, intravenous injection of PLGA@OMNP@ CPT-11-CET followed by guidance with a magnetic field provided the best treatment efficacy with the lowest tumor-associated signal intensity from bioluminescence imaging. Full article

(This article belongs to the Special Issue Advances in Functional Magnetic Nanomaterials)

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14 pages, 6093 KiB

Open AccessEditor’s ChoiceArticle

Study of the Mineralogical Composition of an Alumina–Silica Binder System Formed by the Sol–Gel Method

by Lenka Nevřivová and David Zemánek

Materials 2023, 16(15), 5466; https://doi.org/10.3390/ma16155466 - 4 Aug 2023

Cited by 5 | Viewed by 1782

Abstract

Colloidal bonds are realized by sol–gel technology. The binder system of the refractory castable belongs to the Al₂O₃–SiO₂ binary diagram. Mullite is the most thermally stable mineral in this system. This work was motivated by an attempt to [...] Read more.

Colloidal bonds are realized by sol–gel technology. The binder system of the refractory castable belongs to the Al₂O₃–SiO₂ binary diagram. Mullite is the most thermally stable mineral in this system. This work was motivated by an attempt to maximize the mullite content in the NCC binder system, because a high content of mullite is a guarantee of the long service life of refractories. Initially, the mineralogical composition of the pure gel was tested after drying and firing at temperatures between 1000 °C and 1600 °C. The behavior of the gel during drying was described. Subsequently, a method of minimizing gel shrinkage during drying was sought. To this aim, fine fillers (microfillers) of alumina and silica were tested. In particular, the reactivity of the microfillers, the ability of the microfillers to react with the sol to form mullite, and the drying shrinkage of the microfiller-doped gel were evaluated. The study showed that the least suitable source of Al₂O₃ in terms of its reactivity is tabular corundum, which produces the lowest amount of mullite. The internal structure of the prepared binder system when using different microfillers was described. Based on the results from the second stage of the work, several complete matrixes of the binder system were designed and the degree of their mullitization at different firing temperatures was studied. During this stage, it was shown that the degree of mullitization of the binder system depends mainly on the microsilica content. In the binder system, the maximum mullite content recorded was 76%. The effect of amorphous SiO₂ on the bulk density and internal structure of the binder system was also described. Full article

(This article belongs to the Special Issue Advanced Ceramics Composites and Its Applications)

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14 pages, 5161 KiB

Open AccessEditor’s ChoiceArticle

Enhanced Photoelectrochemical Water Oxidation Using TiO₂-Co₃O₄ p–n Heterostructures Derived from in Situ-Loaded ZIF-67

by Chau Thi Thanh Thu, Hyo Jeong Jo, Ganesh Koyyada, Dae-Hwan Kim and Jae Hong Kim

Materials 2023, 16(15), 5461; https://doi.org/10.3390/ma16155461 - 4 Aug 2023

Cited by 6 | Viewed by 2051

Abstract

Exposing catalytically active metal sites in metal–organic frameworks (MOFs) while maintaining porosity is beneficial for increasing electron transport to achieve better electrochemical energy conversion performance. Herein, we propose an in situ method for MOF formation and loading onto TiO₂ nanorods (NR) using [...] Read more.

Exposing catalytically active metal sites in metal–organic frameworks (MOFs) while maintaining porosity is beneficial for increasing electron transport to achieve better electrochemical energy conversion performance. Herein, we propose an in situ method for MOF formation and loading onto TiO₂ nanorods (NR) using a simple solution-processable method followed by annealing to obtain TiO₂-Co₃O₄. The as-prepared TiO₂-ZIF-67 based photoanodes were annealed at 350, 450, and 550 °C to study the effect of carbonization on photo-electrochemical water oxidation. The successful loading of ZIF-67 on TiO₂ and the formation of TiO₂-Co₃O₄ heterojunction were confirmed by XRD, XPS, FE-SEM, and HRTEM analyses. TiO₂-Co₃O₄-450 (the sample annealed at 450 °C) showed an enhanced photocurrent of 2.4 mA/cm², which was 2.6 times larger than that of pristine TiO₂. The improved photocurrent might be ascribed to the prepared p–n heterostructures (Co₃O₄ and TiO₂), which promote electron–hole separation and charge transfer within the system and improve the photoelectrochemical performance. Moreover, the preparation of Co₃O₄ from the MOF carbonization process improved the electrical conductivity and significantly increased the number of exposed active sites and enhanced the photoresponse performance. The as-prepared ZIF-67 derived TiO₂-Co₃O₄ based photoanodes demonstrate high PEC water oxidation, and the controlled carbonization method paves the way toward the synthesis of low-cost and efficient electrocatalysts. Full article

(This article belongs to the Special Issue Novel Approaches to Photoelectrochemical and Electrochemical Nanomaterials)

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16 pages, 16702 KiB

Open AccessEditor’s ChoiceArticle

Effect of Cu as a Minority Alloying Element on the Corrosion Behaviour of Amorphous and Crystalline Al-Ni-Si Alloy

by Vanya Dyakova, Yoanna Kostova, Boriana Tzaneva, Hristina Spasova and Daniela Kovacheva

Materials 2023, 16(15), 5446; https://doi.org/10.3390/ma16155446 - 3 Aug 2023

Cited by 2 | Viewed by 1543

Abstract

The effect of copper as a minority alloying element on the corrosion behaviour of amorphous and crystalline Al₇₄Ni₁₆Si₁₀ and Al₇₄Ni₁₅Si₉Cu₂ alloys was investigated in this study. Amorphous alloys were produced as [...] Read more.

The effect of copper as a minority alloying element on the corrosion behaviour of amorphous and crystalline Al₇₄Ni₁₆Si₁₀ and Al₇₄Ni₁₅Si₉Cu₂ alloys was investigated in this study. Amorphous alloys were produced as rapidly solidified ribbons using the Chill Block Melt Spinning (CBMS) method and subsequently annealed to complete crystallisation. The corrosion rate of alloys was obtained through continuous immersion tests in 3.5% NaCl at 25 °C and 50 °C for 360 h. The electrochemical parameters corrosion current density (J_corr) and corrosion potential (E_corr) were determined via the potentiodynamic polarisation test. The results showed better corrosion characteristics of amorphous alloys. The addition of 2 at.% copper to the Al₇₄Ni₁₆Si₁₀ alloy improved pitting corrosion resistance without significant effect on the corrosion current and potential. In immersion tests at 25 °C, the presence of copper resulted in an increase in the corrosion rate of about 300% for both amorphous and crystalline alloys. At a temperature of 50 °C, this increase is on average 130%. The apparent difference between the results of the two test methods is discussed in terms of the imperfections on the surface of rapidly solidified ribbons. The results of this study will contribute to a more complex understanding of the nature of amorphous alloys and their application. Full article

(This article belongs to the Special Issue Size-Dependent Effects in Materials for Environmental Protection and Energy Application)

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13 pages, 4429 KiB

Open AccessEditor’s ChoiceArticle

Nonlinear Optical Properties of Zn(II) Porphyrin, Graphene Nanoplates, and Ferrocene Hybrid Materials

by Francesca Limosani, Francesca Tessore, Alessandra Forni, Angelo Lembo, Gabriele Di Carlo, Cecilia Albanese, Stefano Bellucci and Pietro Tagliatesta

Materials 2023, 16(15), 5427; https://doi.org/10.3390/ma16155427 - 2 Aug 2023

Cited by 3 | Viewed by 1742

Abstract

Following some previous work by some of us on the second order nonlinear optical (NLO) properties of Zn(II) meso-tetraphenylporphyrin (ZnP), fullerene, and ferrocene (Fc) diads and triads, in the present research, we explore the NLO response of some new hybrids with two-dimensional [...] Read more.

Following some previous work by some of us on the second order nonlinear optical (NLO) properties of Zn(II) meso-tetraphenylporphyrin (ZnP), fullerene, and ferrocene (Fc) diads and triads, in the present research, we explore the NLO response of some new hybrids with two-dimensional graphene nanoplates (GNP) instead of a zero-dimensional fullerene moiety as the acceptor unit. The experimental data, collected by Electric Field Induced Second Harmonic generation (EFISH) technique in CH₂Cl₂ solution with a 1907 nm incident wavelength, combined with Coupled-Perturbed (CP) and Finite Field (FF) Density Functional Theory (DFT) calculations, show a strongly enhanced contribution of the cubic electronic term γ(−2ω; ω, ω, 0), due to the extended π-conjugation of the carbonaceous acceptor moiety. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

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15 pages, 5092 KiB

Open AccessEditor’s ChoiceArticle

SiC Doping Impact during Conducting AFM under Ambient Atmosphere

by Christina Villeneuve-Faure, Abdelhaq Boumaarouf, Vishal Shah, Peter M. Gammon, Ulrike Lüders and Rosine Coq Germanicus

Materials 2023, 16(15), 5401; https://doi.org/10.3390/ma16155401 - 1 Aug 2023

Cited by 1 | Viewed by 2059

Abstract

The characterization of silicon carbide (SiC) by specific electrical atomic force microscopy (AFM) modes is highly appreciated for revealing its structure and properties at a nanoscale. However, during the conductive AFM (C-AFM) measurements, the strong electric field that builds up around and below [...] Read more.

The characterization of silicon carbide (SiC) by specific electrical atomic force microscopy (AFM) modes is highly appreciated for revealing its structure and properties at a nanoscale. However, during the conductive AFM (C-AFM) measurements, the strong electric field that builds up around and below the AFM conductive tip in ambient atmosphere may lead to a direct anodic oxidation of the SiC surface due to the formation of a water nanomeniscus. In this paper, the underlying effects of the anodization are experimentally investigated for SiC multilayers with different doping levels by studying gradual SiC epitaxial-doped layers with nitrogen (N) from 5 × 10¹⁷ to 10¹⁹ at/cm³. The presence of the water nanomeniscus is probed by the AFM and analyzed with the force–distance curve when a negative bias is applied to the AFM tip. From the water meniscus breakup distance measured without and with polarization, the water meniscus volume is increased by a factor of three under polarization. AFM experimental results are supported by electrostatic modeling to study oxide growth. By taking into account the presence of the water nanomeniscus, the surface oxide layer and the SiC doping level, a 2D-axisymmetric finite element model is developed to calculate the electric field distribution nearby the tip contact and the current distributions at the nanocontact. The results demonstrate that the anodization occurred for the conductive regime in which the current depends strongly to the doping; its threshold value is 7 × 10¹⁸ at/cm³ for anodization. Finally, the characterization of a classical planar SiC-MOSFET by C-AFM is examined. Results reveal the local oxidation mechanism of the SiC material at the surface of the MOSFET structure. AFM topographies after successive C-AFM measurements show that the local oxide created by anodization is located on both sides of the MOS channel; these areas are the locations of the highly n-type-doped zones. A selective wet chemical etching confirms that the oxide induced by local anodic oxidation is a SiOCH layer. Full article

(This article belongs to the Special Issue Silicon Carbide: Material Growth, Device Processing and Applications)

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18 pages, 4139 KiB

Open AccessEditor’s ChoiceArticle

Hierarchical Zeolites Containing Vanadium or Tantalum and Their Application in Cyclohexene Epoxidation Reaction

by Paulina Szczyglewska, Agnieszka Feliczak-Guzik, Sylwia Chałupniczak and Izabela Nowak

Materials 2023, 16(15), 5383; https://doi.org/10.3390/ma16155383 - 31 Jul 2023

Viewed by 1389

Abstract

The aim of this study was the synthesis, characterization, and catalytic application of new hierarchical materials modified with tantalum and vanadium ions. These materials exhibit secondary porosity, thus allowing the reactant molecules to access the active sites of the material while maintaining the [...] Read more.

The aim of this study was the synthesis, characterization, and catalytic application of new hierarchical materials modified with tantalum and vanadium ions. These materials exhibit secondary porosity, thus allowing the reactant molecules to access the active sites of the material while maintaining the acidity and crystallinity of the zeolites. Based on the results, these systems were found to be highly active and selective in the oxidation of cyclohexene. The performance of the catalysts was compared in oxidation processes carried out by conventional and microwave-assisted methods. Microwave-assisted experiments showed that in the presence of a hierarchical FAU zeolite containing Ta, long reaction times could be shortened with increased activity and selectivity under the same residual experimental conditions. Full article

(This article belongs to the Special Issue Advanced Materials in Catalysis and Adsorption (Volume II))

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15 pages, 6437 KiB

Open AccessEditor’s ChoiceArticle

Electrochemical Response of 3D-Printed Free-Standing Reduced Graphene Oxide Electrode for Sodium Ion Batteries Using a Three-Electrode Glass Cell

by Cristina Ramírez, María Isabel Osendi, Juan José Moyano, Jadra Mosa and Mario Aparicio

Materials 2023, 16(15), 5386; https://doi.org/10.3390/ma16155386 - 31 Jul 2023

Cited by 8 | Viewed by 1903

Abstract

Graphene and its derivatives have been widely used to develop novel materials with applications in energy storage. Among them, reduced graphene oxide has shown great potential for more efficient storage of Na ions and is a current target in the design of electrodes [...] Read more.

Graphene and its derivatives have been widely used to develop novel materials with applications in energy storage. Among them, reduced graphene oxide has shown great potential for more efficient storage of Na ions and is a current target in the design of electrodes for environmentally friendly Na ion batteries. The search for more sustainable and versatile manufacturing processes also motivates research into additive manufacturing electrodes. Here, the electrochemical responses of porous 3D-printed free-standing log-type structures fabricated using direct ink writing (DIW) with a graphene oxide (GO) gel ink are investigated after thermal reduction in a three-electrode cell configuration. The structures delivered capacities in the range of 50–80 mAh g⁻¹ and showed high stability for more than 100 cycles. The reaction with the electrolyte/solvent system, which caused an initial capacity drop, was evidenced by the nucleation of various Na carbonates and Na₂O. The incorporation of Na into the filaments of the structure was verified with transmission electron microscopy and Raman spectroscopy. This work is a proof of concept that structured reduced GO electrodes for Na ion batteries can be achieved from a simple, aqueous GO ink through DIW and that there is scope for improving their performance and capacity. Full article

(This article belongs to the Section Carbon Materials)

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23 pages, 5145 KiB

Open AccessEditor’s ChoiceArticle

High-Pressure Synthesis and the Enhancement of the Superconducting Properties of FeSe_0.5Te_0.5

by Mohammad Azam, Manasa Manasa, Tatiana Zajarniuk, Ryszard Diduszko, Tomasz Cetner, Andrzej Morawski, Jarosław Więckowski, Andrzej Wiśniewski and Shiv J. Singh

Materials 2023, 16(15), 5358; https://doi.org/10.3390/ma16155358 - 30 Jul 2023

Cited by 10 | Viewed by 3534

Abstract

A series of FeSe_0.5Te_0.5 bulk samples have been prepared using the high gas pressure and high-temperature synthesis (HP-HTS) method to optimize the growth conditions for the first time and investigated for their superconducting properties using structural, microstructure, transport, and magnetic [...] Read more.

A series of FeSe_0.5Te_0.5 bulk samples have been prepared using the high gas pressure and high-temperature synthesis (HP-HTS) method to optimize the growth conditions for the first time and investigated for their superconducting properties using structural, microstructure, transport, and magnetic measurements to reach the final conclusions. Ex situ and in situ processes are used to prepare bulk samples under a range of growth pressures using Ta-tube and without Ta-tube. The parent compound synthesized by convenient synthesis method at ambient pressure (CSP) exhibits a superconducting transition temperature of 14.8 K. Our data demonstrate that the prepared FeSe_0.5Te_0.5 sealed in a Ta-tube is of better quality than the samples without a Ta-tube, and the optimum growth conditions (500 MPa, 600 °C for 1 h) are favorable for the development of the tetragonal FeSe_0.5Te_0.5 phase. The optimum bulk FeSe_0.5Te_0.5 depicts a higher transition temperature of 17.3 K and a high critical current density of the order of >10⁴ A/cm² at 0 T, which is improved over the entire magnetic field range and almost twice higher than the parent compound prepared using CSP. Our studies confirm that the high-pressure synthesis method is a highly efficient way to improve the superconducting transition, grain connectivity, sample density, and pinning properties of a superconductor. Full article

(This article belongs to the Special Issue Characterization and Application of Superconducting Materials)

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24 pages, 3248 KiB

Open AccessEditor’s ChoiceReview

Nanoparticles in Cancer Diagnosis and Treatment

by Jaya Baranwal, Brajesh Barse, Amalia Di Petrillo, Gianluca Gatto, Luca Pilia and Amit Kumar

Materials 2023, 16(15), 5354; https://doi.org/10.3390/ma16155354 - 30 Jul 2023

Cited by 65 | Viewed by 5816

Abstract

The use of tailored medication delivery in cancer treatment has the potential to increase efficacy while decreasing unfavourable side effects. For researchers looking to improve clinical outcomes, chemotherapy for cancer continues to be the most challenging topic. Cancer is one of the worst [...] Read more.

The use of tailored medication delivery in cancer treatment has the potential to increase efficacy while decreasing unfavourable side effects. For researchers looking to improve clinical outcomes, chemotherapy for cancer continues to be the most challenging topic. Cancer is one of the worst illnesses despite the limits of current cancer therapies. New anticancer medications are therefore required to treat cancer. Nanotechnology has revolutionized medical research with new and improved materials for biomedical applications, with a particular focus on therapy and diagnostics. In cancer research, the application of metal nanoparticles as substitute chemotherapy drugs is growing. Metals exhibit inherent or surface-induced anticancer properties, making metallic nanoparticles extremely useful. The development of metal nanoparticles is proceeding rapidly and in many directions, offering alternative therapeutic strategies and improving outcomes for many cancer treatments. This review aimed to present the most commonly used nanoparticles for cancer applications. Full article

(This article belongs to the Special Issue Nanomaterials for Medical Application (Second Volume))

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21 pages, 18129 KiB

Open AccessEditor’s ChoiceArticle

The Effects of Partial Replacement of Ground Granulated Blast Furnace Slag by Ground Wood Ash on Alkali-Activated Binder Systems

by Ece Ezgi Teker Ercan, Andrzej Cwirzen and Karin Habermehl-Cwirzen

Materials 2023, 16(15), 5347; https://doi.org/10.3390/ma16155347 - 29 Jul 2023

Cited by 6 | Viewed by 2470

Abstract

Cement production contributes significantly to carbon dioxide emissions. Alkali-activated materials offer an environmentally friendly alternative due to their comparable strength, durability and low-carbon emissions while utilizing wastes and industrial by-products. Wood ash is a waste material that shows promising results as a partial [...] Read more.

Cement production contributes significantly to carbon dioxide emissions. Alkali-activated materials offer an environmentally friendly alternative due to their comparable strength, durability and low-carbon emissions while utilizing wastes and industrial by-products. Wood ash is a waste material that shows promising results as a partial replacement for Portland cement and precursors in alkali-activated systems. The aim of this study was to examine the effect of ground wood ash on the mechanical properties of alkali-activated mortars. Wood ash was incorporated as a 0 wt%, 10 wt% and 20 wt% partial replacement for ground granulated blast furnace slag (GGBFS). The wood ashes were ground in a planetary ball mill for 10 and 20 min. Sodium silicate (Na₂SiO₃), sodium carbonate (Na₂CO₃), and sodium hydroxide (NaOH) were used as alkali activators. The results demonstrated that ground wood ash improved the mechanical properties of alkali-activated systems compared to untreated wood ash. However, the incorporation of wood ash increased the porosity of the binder matrix. Full article

(This article belongs to the Special Issue Advances in Sustainable Construction and Building Materials)

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16 pages, 4423 KiB

Open AccessEditor’s ChoiceArticle

Influence of Pre-Tension on Free-End Torsion Behavior and Mechanical Properties of an Extruded Magnesium Alloy

by Hongbing Chen, Zhikang Shen, Bo Song and Jia She

Materials 2023, 16(15), 5343; https://doi.org/10.3390/ma16155343 - 29 Jul 2023

Cited by 4 | Viewed by 1456

Abstract

In this study, the influence of pre-tension on free-end torsion behavior and compression mechanical properties and micro-hardness of an extruded AZ31 Mg alloy was investigated using electron backscatter diffraction (EBSD), compression testing and micro-hardness testing. The result indicates that pre-tension can cause significant [...] Read more.

In this study, the influence of pre-tension on free-end torsion behavior and compression mechanical properties and micro-hardness of an extruded AZ31 Mg alloy was investigated using electron backscatter diffraction (EBSD), compression testing and micro-hardness testing. The result indicates that pre-tension can cause significant dislocation strengthening, which can increase the torsion yield strength and make the shear stress–shear strain curve of the pre-tension sample almost parallel to that of the as-extruded sample during plastic deformation stage. Texture in edge position on the cross-section of both the pre-tension and as-extruded samples can be rotated towards the extrusion direction by about ~30° by free-end torsion. The Swift effect is mainly responsible for the occurrence of massive extension twins in the central region. In contrast, normal stress is the main cause of extension twins occurring in the edge region. However, the effect of extension twins on micro-hardness is less than that of dislocations. The micro-hardness of both free-end torsion specimens increases almost linearly with increasing distance from center to edge on the cross-section. Nevertheless, the increase in micro-hardness of the pre-tension and then torsion sample is inconspicuous because pre-tension leads to dislocation proliferation and dislocation accumulation saturation. The result also indicates that both pre-tension and free-end torsion can lead to dislocation strengthening, which can obviously increase the micro-hardness and compressive yield stress. The underlying mechanisms were explored and discussed in detail. Full article

(This article belongs to the Special Issue Research on Forming and Serving Performance of Advanced Alloys)

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2 pages, 157 KiB

Open AccessEditor’s ChoiceEditorial

Finite Element Modeling of Microstructures in Composite Materials: A Special Issue in Materials

by Yunhua Luo

Materials 2023, 16(15), 5332; https://doi.org/10.3390/ma16155332 - 29 Jul 2023

Viewed by 1460

Abstract

This Special Issue of the journal Materials aims to gather recent advancements and novel developments in the field of finite element modeling of microstructures in composite materials [...] Full article

(This article belongs to the Special Issue Finite Element Modeling of Microstructures in Composite Materials)

19 pages, 848 KiB

Open AccessEditor’s ChoiceReview

The Intraoperative Use of Defensive Antibacterial Coating (DAC^®) in the Form of a Gel to Prevent Peri-Implant Infections in Orthopaedic Surgery: A Clinical Narrative Review

by Daniele Pressato, Angela Battista, Marco Govoni, Leonardo Vivarelli, Dante Dallari and Antonio Pellegrini

Materials 2023, 16(15), 5304; https://doi.org/10.3390/ma16155304 - 28 Jul 2023

Cited by 6 | Viewed by 2682

Abstract

Periprosthetic joint infections (PJIs) in arthroplasty and osteosynthesis-associated infections (OAIs) in reconstructive surgery still represent a challenging complication in orthopaedics and traumatology causing a burden worsening the patient’s quality of life, for caregiver and treating physicians, and for healthcare systems. PJIs and OAIs [...] Read more.

Periprosthetic joint infections (PJIs) in arthroplasty and osteosynthesis-associated infections (OAIs) in reconstructive surgery still represent a challenging complication in orthopaedics and traumatology causing a burden worsening the patient’s quality of life, for caregiver and treating physicians, and for healthcare systems. PJIs and OAIs are the result of bacterial adhesion over an implant surface with subsequent biofilm formation. Therefore, the clinical pathological outcome is a difficult-to-eradicate persistent infection. Strategies to treat PJIs and OAIs involve debridement, the replacement of internal fixators or articular prostheses, and intravenous antibiotics. However, long treatments and surgical revision cause discomfort for patients; hence, the prevention of PJIs and OAIs represents a higher priority than treatment. Local antibiotic treatments through coating-release systems are becoming a smart approach to prevent this complication. Hydrophilic coatings, loaded with antibiotics, simultaneously provide a barrier effect against bacterial adhesion and allow for the local delivery of an antibiotic. The intraoperative use of a hyaluronan (HY)-derivative coating in the form of a gel, loaded with antibiotics to prevent PJI, has recently raised interest in orthopaedics. Current evidence supports the use of this coating in the prophylaxis of PJI and IRIs in terms of clinical outcomes and infection reduction. Thus, the purpose of this narrative review is to assess the use of a commercially available HY derivative in the form of a gel, highlighting the characteristics of this biomaterial, which makes it attractive for the management of PJIs and IRIs in orthopaedics and traumatology. Full article

(This article belongs to the Special Issue Synthetic and Biologic Materials for Prosthetic and Reconstructive Applications for Musculoskeletal Tissue)

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