Materials

23 pages, 4582 KiB

Open AccessArticle

Reinforced Fill Structure with Alternative Fill Materials: An Application of Geogrid Creep Strain Analysis Using Numerical Modeling

by Ahsan Rehman Khan and Gemmina Di Emidio

Materials 2025, 18(6), 1346; https://doi.org/10.3390/ma18061346 - 18 Mar 2025

Abstract

For many years, granular fill has been the preferred fill material in reinforced fill structures (RFSs) due to its high strength and drainage properties. However, the global scarcity of granular fill has necessitated the exploration of alternative fill materials. This study aims to [...] Read more.

For many years, granular fill has been the preferred fill material in reinforced fill structures (RFSs) due to its high strength and drainage properties. However, the global scarcity of granular fill has necessitated the exploration of alternative fill materials. This study aims to evaluate the performance of three different alternative fill materials: (i) weak onsite fill (fill 1), (ii) lime-stabilized onsite fill (fill 2), and (iii) recycled construction and demolition (C & D) waste (fill 3). A finite element analysis (FEA) was conducted to assess the stability and horizontal displacement of an RFS and the long-term creep deformation of geogrid using viscoelastic (time-dependent) model in Plaxis. This RFS comprised a combination of wire mesh and geogrids, serving as primary and secondary reinforcement materials, respectively. The results indicate that fill 1, with low shear strength and stiffness, induces excessive lateral displacement and was unstable, making it unsuitable for RFS applications. In contrast, Fill 2 and Fill 3 achieve Eurocode-based safety factors of 1.12 and 1.19, respectively, while significantly reducing horizontal displacement. The long-term creep deformation analysis of geogrid in the case of fill 1 exceeds the prescribed serviceability strain limit threshold, while in the cases of fill 2 and fill 3, it conforms to the serviceability strain limit, which indicates effective mobilization of tensile resistance without excessive elongation. Finally, an analysis was conducted to optimize the geogrid length and to see its impact on cost and performance. The results revealed up to a 29% cost reduction while ensuring performance criteria. These findings validate lime-stabilized onsite fill and recycled C&D waste as viable, cost-effective alternatives to conventional granular backfill, ensuring not only stability and serviceability but also the long-term performance of geogrids in RFSs. Full article

(This article belongs to the Section Advanced Materials Characterization)

21 pages, 1537 KiB

Open AccessArticle

Contribution of Oxygen and Ultraviolet Light to the Adhesion Properties of Warm Mix Asphalt During the Light-Oxidative Coupling Ultraviolet Aging Process

by Jianbing Ma, Bo Li, Yongning Wang, Xiaomin Li, Dongna Li, Xiaoyu Ren and Mingxing Fu

Materials 2025, 18(6), 1345; https://doi.org/10.3390/ma18061345 - 18 Mar 2025

Abstract

Objective: We investigated the contribution of oxygen and UV light to the UV aging process of warm mix asphalt (WMA). Methods: In this paper, warm mix asphalt was prepared with different aging methods (RTFOT, PAV and UV) and UV aging times (50 h, [...] Read more.

Objective: We investigated the contribution of oxygen and UV light to the UV aging process of warm mix asphalt (WMA). Methods: In this paper, warm mix asphalt was prepared with different aging methods (RTFOT, PAV and UV) and UV aging times (50 h, 100 h, 150 h and 200 h). The cohesion and bonding functions of WMA were tested using surface free energy theory. In addition, the UV aging functional groups of WMA were analyzed using Fourier transform infrared spectroscopy (FTIR). On this basis, the contribution of oxygen and ultraviolet light to the UV aging of WMA was analyzed using the random forest model. Results and conclusions: The results showed that UV aging had the greatest effect on the adhesion property index and functional group index of WMA, followed by PAV aging, and RTFOT aging had the least effect. With the extension of UV aging time, the adhesion and cohesion functions of WMA showed a decreasing trend, while the carbonyl index and sulfoxide index showed an increasing trend. When the UV aging time exceeded 150 h, the adhesion function and functional group index of WMA gradually tended to stabilize. The effect of UV aging on the adhesive properties of WMA was mainly due to adhesive damage. There were significant differences in the effects of oxygen isolation and light–oxygen-coupled UV aging on the adhesive properties and functional group index of WMA. In the light–oxygen-coupled UV aging of warm mix asphalt, the contribution of UV radiation was 79.9%, and the contribution of oxygen was 20.1%. Full article

(This article belongs to the Special Issue Development of Sustainable Asphalt Materials)

14 pages, 4683 KiB

Open AccessArticle

Sustainable Additive Manufacturing of IN718 Blades: Powder Recycling Strategies for Reduced Carbon Footprint

by Xunchen Liu, Yilun Wang, Tengyuan Fang, Wenxuan Wang, Zhiheng Hu, Yang Meng, Bo Huang, Yuan Fang, Lin Hua and Mingzhang Chen

Materials 2025, 18(6), 1344; https://doi.org/10.3390/ma18061344 - 18 Mar 2025

Abstract

With the growing demand for aero-engine turbine blades, the resource consumption and environmental impact of superalloy powder in the manufacturing process have become increasingly significant. This study focuses on IN718 nickel-based superalloy powder and establishes a recycling method based on powder mixing. By [...] Read more.

With the growing demand for aero-engine turbine blades, the resource consumption and environmental impact of superalloy powder in the manufacturing process have become increasingly significant. This study focuses on IN718 nickel-based superalloy powder and establishes a recycling method based on powder mixing. By mixing sieved recycled powder with new powder at a 1:1 mass ratio, comprehensive characterization tests, including powder morphology analysis, particle size distribution, blade printability evaluation, mechanical property tests (tensile strength at both 25 °C and 650 °C), and microhardness measurements, demonstrated that the blended powder maintained performance characteristics comparable to new powder, with no statistically significant differences observed. Furthermore, this study introduces the life cycle assessment (LCA) methodology into the field of superalloy powder recycling, providing a novel technical approach for sustainable development in aerospace manufacturing. A quantitative analysis of environmental impacts throughout the blended powder recycling process indicates that this method can reduce carbon emissions by 45% and energy consumption by 48%. Full article

(This article belongs to the Special Issue Recent Advances in Stainless Steel: Characterization, Properties and Applications)

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13 pages, 4527 KiB

Open AccessArticle

Oxygen Vacancy Modification MIL-125(Ti) Promotes CO₂ Photoreduction to CO with Near 100% Selectivity

by Hangmin Xu, Hao Song, Xiaozhi Wang and Xingwang Zhu

Materials 2025, 18(6), 1343; https://doi.org/10.3390/ma18061343 - 18 Mar 2025

Abstract

The substantial release of industrial carbon dioxide has been identified as a key factor in the development of various environmental issues. In addressing these concerns, the utilization of photocatalytic technology for carbon reduction has garnered significant attention. The disadvantage of CO₂ photoreduction [...] Read more.

The substantial release of industrial carbon dioxide has been identified as a key factor in the development of various environmental issues. In addressing these concerns, the utilization of photocatalytic technology for carbon reduction has garnered significant attention. The disadvantage of CO₂ photoreduction is the problem of product yield and selectivity. It is known that MIL-125(Ti) with a high specific surface area (S_BET) possesses more active sites using Ti as a node. The calcination of MIL-125(Ti) in a reducing atmosphere has been shown to introduce oxygen vacancies (O_V), thereby enhancing the material’s surface and internal pores. This process has been demonstrated to result in a significant increase in the S_BET and an enhancement of the Ti³⁺/Ti⁴⁺ ratio. The increased Ti³⁺ centers have been found to improve the material’s reducing properties. The results demonstrate that the O_V-rich MIL-125-2H material exhibits the high-performance and highly selective photoreduction in CO₂. Full article

(This article belongs to the Special Issue Advanced Materials for Solar Energy Utilization)

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23 pages, 2190 KiB

Open AccessArticle

Simplified Mechanistic Aging Model for Lithium Ion Batteries in Large-Scale Applications

by Zhe Lv, Huinan Si, Zhe Yang, Jiawen Cui, Zhichao He, Lei Wang, Zhe Li and Jianbo Zhang

Materials 2025, 18(6), 1342; https://doi.org/10.3390/ma18061342 - 18 Mar 2025

Abstract

Energy storage systems play a vital role in balancing solar- and wind-generated power. However, the uncertainty of their lifespan is a key factor limiting their large-scale applications. While currently reported battery aging models, empirical or semi-empirical, are capable of accurately assessing battery decay [...] Read more.

Energy storage systems play a vital role in balancing solar- and wind-generated power. However, the uncertainty of their lifespan is a key factor limiting their large-scale applications. While currently reported battery aging models, empirical or semi-empirical, are capable of accurately assessing battery decay under specific operating conditions, they cannot reliably predict the battery lifespan beyond the measured data. Moreover, these models generally require a tedious procedure to determine model parameters, reducing their value for onsite applications. This paper, based on Newman’s pseudo-2D performance model and incorporating microparameters obtained from cell disassembly, developed a mechanistic model accounting for three major aging mechanisms of lithium iron phosphate/graphite cells, i.e., solid electrolyte interphase growth, lithium plating, and gas generation. The prediction of this mechanistic model agrees with the experimental results within an average error of ±1%. The mechanistic model was further simplified into an engineering model consisting of only two core parameters, loss of active lithium and loss of active material, and was more suitable for large-scale applications. The accuracy of the engineering model was validated in a 100 MW/200 MWh energy storage project. When the actual State of Health (SOH) of the battery degraded to 89.78%, the simplified model exhibited an error of −0.17%, and the computation time decreased from 8.12 h to 10 s compared to the mechanistic model. Full article

(This article belongs to the Special Issue Advanced Electrode Materials for Lithium-Ion and Sodium-Ion Secondary Batteries)

14 pages, 8784 KiB

Open AccessArticle

Formation of Ultrafine-Grained Dual-Phase Microstructure by Warm Deformation of Austenite in High-Strength Steel

by Wen Shu, Yingqi Fan, Rengeng Li, Qing Liu and Qingquan Lai

Materials 2025, 18(6), 1341; https://doi.org/10.3390/ma18061341 - 18 Mar 2025

Abstract

Thermomechanical processing by applying deformation-induced ferrite transformation (DIFT) is an effective method of producing ultrafine-grained (UFG) ferritic steels, which usually present high yield strength but low strain hardening. In this study, we explored the concept of DIFT in the processing of UFG dual-phase [...] Read more.

Thermomechanical processing by applying deformation-induced ferrite transformation (DIFT) is an effective method of producing ultrafine-grained (UFG) ferritic steels, which usually present high yield strength but low strain hardening. In this study, we explored the concept of DIFT in the processing of UFG dual-phase (DP) steel, in order to improve its strain hardening capability and thus its ductility. The processing temperature was reduced to enhance the dislocation storage in austenite. It was found that the warm deformation of austenite induced a dramatic occurrence of DIFT, resulting in the formation of UFG-DP microstructures along the whole thickness of the specimen. In the UFG-DP microstructure, the average ferrite grain size was 1.2 μm and the ferrite volume fraction was 44 vol.%. The observation of twinned martensite suggests the occurrence of carbon partitioning during the DIFT process. The UFG-DP microstructure exhibited a good combination of strength and ductility, which was enabled by the synergy of the ultrafine ferrite grains and the efficient composite effect. The outcome of this study provides a novel pathway to develop advanced hot-rolled steels with a UFG-DP microstructure and which are associated with the advantages of their readiness to be scaled up and low costs. Full article

(This article belongs to the Special Issue Heat Treatment and Additive Manufacturing of Alloys: Processing, Properties and Simulations)

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33 pages, 12074 KiB

Open AccessArticle

PVP as an Oxygen Vacancy-Inducing Agent in the Development of Black 45S5 Bioactive Glass Fibrous Scaffolds Doped with Zn and Mg Using A-HSBS

by Keila C. Costa, Maria Geórgia da S. Andrade, Rondinele N. de Araujo, Adegildo R. de Abreu Junior, Marianna V. Sobral, Juan Carlos R. Gonçalves, Bianca V. Sousa, Gelmires A. Neves and Romualdo R. Menezes

Materials 2025, 18(6), 1340; https://doi.org/10.3390/ma18061340 - 18 Mar 2025

Abstract

Currently, there is an increasing demand for advanced materials that can address the needs of tissue engineering and have the potential for use in treatments targeting tumor cells, such as black bioactive materials in photothermal therapy. Thus, 3D fibrous scaffolds of black 45S5 [...] Read more.

Currently, there is an increasing demand for advanced materials that can address the needs of tissue engineering and have the potential for use in treatments targeting tumor cells, such as black bioactive materials in photothermal therapy. Thus, 3D fibrous scaffolds of black 45S5 bioactive glass were produced using the air-heated solution blow spinning (A-HSBS) technique, with polyvinylpyrrolidone (PVP) serving as a spinning aid and an oxygen vacancy-inducing agent. Glass powder with the same composition was synthesized via the sol-gel route for comparison. The samples were characterized using thermogravimetric analysis, X-ray diffraction, FTIR spectroscopy, and scanning electron microscopy, along with in vitro tests using simulated body fluid (SBF), phosphate-buffered saline (PBS), and TRIS solution. The results showed that PVP enhanced oxygen vacancy formation and stabilized the scaffolds at 600 °C. Doping with Zn and Mg ions reduced crystallization while significantly increasing the fiber diameters. Scaffolds doped with Zn exhibited lower degradation rates, delayed apatite formation, and hindered ionic release. Conversely, Mg ions facilitated greater interaction with the medium and rapid apatite formation, completely covering the fibers. The scaffolds showed no cytotoxicity in the MTT assay at concentrations of up to 200 µg/mL for HaCat cells and 0.8 mg/mL for L929 cells. This study demonstrated the effectiveness of using PVP in the production of black bioactive glass scaffolds, highlighting their potential for bone regeneration. Full article

(This article belongs to the Special Issue Materials for Drug Delivery and Medical Engineering)

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35 pages, 12953 KiB

Open AccessArticle

Two-Dimensional Finite Element Analysis and Cutting Force Model for the Cutting of Circular Steel Bars Using Negative Rake Angle Cutters: Accounting for Chip Accumulation Effects

by Shifan Qiao, Chaobo Feng, Gang Wang, Taofu Liu and Jenisha Singh

Materials 2025, 18(6), 1339; https://doi.org/10.3390/ma18061339 - 18 Mar 2025

Abstract

The cutting force exerted on steel bars plays a crucial role in determining tunneling parameters for shield tunneling, especially when cutters are used to cut through existing pile foundations. This research focuses on the cutting force during the initial phase of the cutting [...] Read more.

The cutting force exerted on steel bars plays a crucial role in determining tunneling parameters for shield tunneling, especially when cutters are used to cut through existing pile foundations. This research focuses on the cutting force during the initial phase of the cutting process. Using 2D finite element analysis, this study examines the early stage of orthogonal cutting with negative rake angle cutters, exploring the formation of a slip plane mode. By combining slip line theory with the shear band model, a computational model is developed to calculate the cutting force for negative rake angle cutters when cutting a circular steel bar cross-section at various depths. In addition, with the incorporation of the Johnson–Cook model, this study models cutting forces under various conditions, taking into account factors such as material strength, strain rate sensitivity, and temperature effects. The steels studied include AISI 1040, AISI 4340, and AISI 304, which are commonly used in construction, with attention given to how their mechanical properties, such as strength and hardness, affect the cutting forces. While this study acknowledges the steels’ manufacturing conditions, the primary focus remains on the cutting process and its impact on force predictions. The model’s calculated horizontal cutting force is compared to numerical simulations, showing a maximum absolute error of 33.85% and an average error of 14.23%. The vertical cutting force calculations are less accurate, with a maximum error of 64.2% and an average error of 14.06%. The analysis further reveals that chip accumulation significantly impacts the horizontal cutting force, while the variation in average stress along the slip line has a smaller effect. This study also examines how factors like material properties, initial temperature, low friction coefficients, and steel bar radius contribute to the model’s accuracy and reliability. Full article

(This article belongs to the Topic Smart Material and Smart Construction Technologies for Urban Development)

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16 pages, 3676 KiB

Open AccessArticle

Sorption and Desorption Isotherms of Lightweight Alkali-Activated Materials Modified with Silica Aerogel

by Halina Garbalińska, Agata Stolarska, Jarosław Strzałkowski and Agnieszka Ślosarczyk

Materials 2025, 18(6), 1338; https://doi.org/10.3390/ma18061338 - 18 Mar 2025

Abstract

The moisture content in a building material has a negative impact on its technical parameters. This problem applies in particular to highly porous materials, including those based on aerogel. This paper presents moisture tests on a new generation of alkali-activated materials (AAMs) with [...] Read more.

The moisture content in a building material has a negative impact on its technical parameters. This problem applies in particular to highly porous materials, including those based on aerogel. This paper presents moisture tests on a new generation of alkali-activated materials (AAMs) with different aerogel contents. Silica aerogel particles were used as a partial replacement for the lightweight sintered fly ash-based aggregate at levels of 10, 20, and 30 vol%. The experiment included four formulations: R0 (without the addition of aerogel) and the recipes R1, R2, and R3, with an increasing content of this additive. The level at which moisture stabilizes in a material in contact with the environment of a given humidity and temperature depends on whether the equilibrium state is reached in the process of moisture absorption by a dry material or in the process of the drying out of a wet material. The equilibrium states achieved in these processes are described by sorption and desorption isotherms, determined at a given temperature, but at different levels of relative humidity. The SSS (saturation salt solution) method has been used for years to determine them. Unfortunately, measurements carried out using this method are difficult and highly time-consuming. For this reason, a more accurate and faster DVS (dynamic vapor sorption) method was used in this study of R0–R3 composites. The research program assumed 10 step changes in humidity in the sorption processes and 10 step changes in humidity in the desorption processes. As a result, the course of the sorption and desorption isotherms of each of the four composites was accurately reproduced, and the hysteresis scale was assessed, which was most evident in the cases of the R0 composite (made without the addition of aerogel) and R1 composite (made with the lowest aerogel content). Studies have shown that the increased addition of aerogel resulted in an increase in the amount of water absorbed. This was true for all ten relative humidity levels tested. As a result, the highest values in the entire hygroscopic range were observed in the course of the sorption isotherm determined for the R3 composite with the highest aerogel content, and the lowest values were for the sorption isotherm of the R0 composite without the addition of aerogel. Full article

(This article belongs to the Special Issue Special Functional and Environmental Cement-Based Materials)

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11 pages, 2625 KiB

Open AccessArticle

Sodium and Potassium Mixed Effects on the Viscoelastic Behavior of Silicate Glasses

by Fucheng Wu, Yonggang Huang, Haizheng Tao, Peng Jiao, Ziyang Xiao and Jinsheng Jia

Materials 2025, 18(6), 1337; https://doi.org/10.3390/ma18061337 - 18 Mar 2025

Abstract

This study investigated the viscoelastic behavior and structural evolution of silicate glasses with the molar composition 70SiO₂·(30 − x) Na₂O·xK₂O, where the molar ratio r = x/30 varied between 0, 0.25, 0.5, and 0.75. A notable [...] Read more.

This study investigated the viscoelastic behavior and structural evolution of silicate glasses with the molar composition 70SiO₂·(30 − x) Na₂O·xK₂O, where the molar ratio r = x/30 varied between 0, 0.25, 0.5, and 0.75. A notable “V”-shaped trend in relaxation activation energy (ΔH_Gt) was observed, with the energy reaching a minimum of 163.14 kJ/mol at r = 0.5. This trend exhibited a synergistic mixed alkali effect that significantly affected the viscoelastic properties of the glass. Raman spectroscopy analysis revealed dynamic structural reorganization within the [SiO₄] network, transitioning from Q⁴ to Q³ for r < 0.5 and reverting to Q⁴ for r > 0.5 as the K₂O content increased. These structural transformations provide atomic-scale evidence for the observed viscoelastic behavior. The findings offer critical insights into the mixed alkali effect on viscoelasticity, establishing a theoretical foundation for optimizing clad materials in optical fiber imaging arrays. Full article

(This article belongs to the Special Issue Advancements in Optical Materials and Photonic Device Technologies)

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18 pages, 8559 KiB

Open AccessArticle

Role of Composition and Temperature in Shaping the Structural and Optical Properties of Iodide-Based Hybrid Perovskite Thin Films Produced by PVco-D Technique

by Agnieszka Marjanowska, Krzysztof Wiśniewski, Przemysław Płóciennik, Bouchta Sahraoui and Anna Zawadzka

Materials 2025, 18(6), 1336; https://doi.org/10.3390/ma18061336 - 18 Mar 2025

Abstract

The research considered in this publication aims to contribute to developing perovskite-based technologies by conducting basic research on perovskite materials. The materials described in the paper are thin films of hybrid perovskite MEAPbI₃ made using the PVco-D method in three different compositions—perovskite [...] Read more.

The research considered in this publication aims to contribute to developing perovskite-based technologies by conducting basic research on perovskite materials. The materials described in the paper are thin films of hybrid perovskite MEAPbI₃ made using the PVco-D method in three different compositions—perovskite samples differ in the percentage of organic methylammonium and inorganic iodide parts. This publication discusses the influence of the composition of the thin perovskite layer on its structural and optical properties and the influence of the temperature of the environment of the perovskite thin film on optical properties. To answer these questions, the surface topography was analyzed using the AFM method, spectroscopic measurements were carried out in the UV-Vis-NIR range, and photoluminescence measurements were performed in a wide temperature range—from about 80 K to 310 K. The results indicate that the composition changes the surface topography, forming increasingly higher crystallites (up to 606%) with increasing methylammonium content. The transition temperature from the orthorhombic to the tetragonal phase was determined for each composition at about 140 K. For the composition of 30% MEAI + 70% PbI2, the phase transition temperature from tetragonal to cubic was determined at a temperature close to RT. Full article

(This article belongs to the Special Issue New Insight into Design and Properties of Nanomaterials (Third Edition))

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16 pages, 6483 KiB

Open AccessArticle

Impact of DC Electric Field Direction on Sedimentation Behavior of Colloidal Particles in Water

by Hiroshi Kimura

Materials 2025, 18(6), 1335; https://doi.org/10.3390/ma18061335 - 18 Mar 2025

Abstract

Colloidal particles in water exhibit increased sedimentation velocity under a horizontal DC electric field of several V/mm compared to no field. Hollow particles with a lower density than water show an increased ascent velocity with the horizontal electric field. These phenomena suggest that [...] Read more.

Colloidal particles in water exhibit increased sedimentation velocity under a horizontal DC electric field of several V/mm compared to no field. Hollow particles with a lower density than water show an increased ascent velocity with the horizontal electric field. These phenomena suggest that colloidal particles form flocs due to the electric field, known as the Electrically Induced Rapid Separation (ERS) effect. This study investigates, for the first time, the impact of the DC electric field direction on the ERS effect. The electric field was defined as horizontal when the inclination angle θ = 0° and vertical at θ = 90°, covering all inclination angles. Results showed that the ERS effect increased for θ < ~20–30° in both upward and downward directions. However, beyond this range, the ERS effect decreased or disappeared. At larger θ values, convection was observed, significantly improving colloidal particle dispersion stability. Additionally, negatively charged particles were observed to be “repelled” near the negative electrode. This study offers new insights into controlling particle dispersion stability using electric fields and suggests potential applications in colloid and material science. Full article

(This article belongs to the Special Issue High-Performance Applications of Advanced Materials: Material Properties, Behaviour Modeling, Optimal Design and Advanced Processes)

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Graphical abstract

24 pages, 5326 KiB

Open AccessReview

Advances in High-Temperature Non-Metallocene Catalysts for Polyolefin Elastomers

by Cheng Wang, Xin Li, Si Chen and Tianyu Shan

Materials 2025, 18(6), 1334; https://doi.org/10.3390/ma18061334 - 18 Mar 2025

Abstract

Despite the great successes achieved by metallocene catalysts in high-value-added polyolefin elastomer, the challenging preparation conditions and undesirable high-temperature molecular weight capabilities have compromised the efficiency and cost of polyolefin in industrial production. Recently, non-metallocene catalysts have received considerable attention due to their [...] Read more.

Despite the great successes achieved by metallocene catalysts in high-value-added polyolefin elastomer, the challenging preparation conditions and undesirable high-temperature molecular weight capabilities have compromised the efficiency and cost of polyolefin in industrial production. Recently, non-metallocene catalysts have received considerable attention due to their high thermostability, especially when coordinated with early transition metals. This review provides an overview of these early transition metal non-metallocene catalysts, which are mainly composed of N,N′-, N,O-, and N,S-bidentate complexes and tridentate complexes. The structural characteristics, catalytic performance, advantages, and disadvantages of the relevant non-metallocene catalysts, as well as their applications, are discussed. Candidates for commercialization of non-metallocene catalysts are proposed—focusing on imine-enamine, amino-quinoline, and pyridine-imine catalysts—by comparing the successful industrialization cases of metallocene catalysts. Finally, the trend in the research on non-metallocene catalysts and the strategies to address the challenges limiting their commercialization are considered. Full article

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28 pages, 106367 KiB

Open AccessArticle

Study and Simulation Analysis of Microwave Heating Performance of Magnetite Concrete Based on Random Aggregate Modeling

by Guoyu Li, Zhenfu Chen, Qiongfang Wu, Dan Wu, Qiuwang Tao, Pinyu Zou and Yizhi Liu

Materials 2025, 18(6), 1333; https://doi.org/10.3390/ma18061333 - 18 Mar 2025

Abstract

Radiation-shielding concrete, widely used in protective structures because of its effective shielding properties, employs magnetite aggregates to achieve higher compressive strength than conventional concrete. However, prolonged exposure to high temperatures leads to mechanical degradation. This study investigates the thermal evolution of magnetite concrete [...] Read more.

Radiation-shielding concrete, widely used in protective structures because of its effective shielding properties, employs magnetite aggregates to achieve higher compressive strength than conventional concrete. However, prolonged exposure to high temperatures leads to mechanical degradation. This study investigates the thermal evolution of magnetite concrete under microwave heating across varying temperatures (38–800 °C). A microwave oven was utilized for heating, and COMSOL Multiphysics was employed to establish an electromagnetic-thermal-mechanical coupled model, analyzing surface characteristics, temperature distribution, stress-strain behavior, and residual compressive strength. Results indicate that internal temperatures exceed surface temperatures during microwave heating, with a maximum temperature difference surpassing 150 °C at 800 °C. Compressive stresses predominantly arise in the mortar, while tensile stresses concentrate in aggregates and the interface transition zone, causing stress concentration. Mortar exhibits greater deformation than aggregates as temperatures increase. Simulated and experimental residual compressive strengths show strong agreement, with a maximum deviation of 7.58%. The most rapid mechanical deterioration occurs at 450–600 °C, marked by a residual compressive strength decline of 0.07 MPa/°C and the formation of penetrating cracks. Full article

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20 pages, 5855 KiB

Open AccessArticle

Investigation on the Ageing Behaviour of High-Modulus Modified Bitumen Based on Rheological and Chemical Approaches

by Xuemao Feng, Xin Li, Mingchen Li, Liping Liu, Zhenbang Cheng and Zhanchuang Han

Materials 2025, 18(6), 1332; https://doi.org/10.3390/ma18061332 - 18 Mar 2025

Abstract

With outstanding resistance for permanent deformation, high-modulus modified bitumen (HMB) has garnered widespread attention in recent years and has been employed in the construction of bitumen pavements across various regions. However, limited research exists on the ageing behaviour of HMB, and conventional short-term [...] Read more.

With outstanding resistance for permanent deformation, high-modulus modified bitumen (HMB) has garnered widespread attention in recent years and has been employed in the construction of bitumen pavements across various regions. However, limited research exists on the ageing behaviour of HMB, and conventional short-term ageing protocols for bitumen may not be applicable to HMB due to its exceptionally high viscosity. Therefore, this study aims to assess the ageing behaviour of HMB and propose a suitable short-term ageing process for HMB utilizing dynamic shear rheometer (DSR) and gel permeation chromatography (GPC) approaches. For comparison purposes, the ageing behaviour of a type of SBS-modified bitumen and a kind of base bitumen were also analyzed. Initially, the study involved a comparison of the properties of bitumen subjected to short-term ageing at various temperatures and those of bitumen within mixtures undergoing short-term oven ageing tests. Subsequently, both the chemical and rheological properties of bitumen under diverse ageing conditions were examined. Finally, investigations were conducted to establish relationships between rheological properties and the molecular weight distribution of HMB. The reported results indicate that the suggested ageing temperature for the thin-film oven test (TFOT) should be increased to 193 °C for HMB, achieving a more accurate simulation of short-term ageing in HMB mixtures during on-site mixing, transport, and paving processes. Compared to base bitumen and SBS-modified bitumen, HMB exhibits superior ageing resistance. Furthermore, the molecular weight distribution of HMB is strongly correlated with its rheological properties. This correlation offers a promising approach to predict the rheological properties of bitumen in HMB mixtures by directly analyzing the chemical molecular weight distribution of the binders, thereby eliminating the need for an extraction process. Full article

(This article belongs to the Section Construction and Building Materials)

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13 pages, 3073 KiB

Open AccessArticle

Electron Screening in Deuteron–Deuteron Reactions on a Zr Target with Oxygen and Carbon Contamination

by Agata Kowalska, Mateusz Kaczmarski, Konrad Czerski, Rakesh Dubey, Gokul Das Haridas, Mathieu Valat, Natalia Targosz-Ślęczka, Paweł Figiel, Justyna Słowik and Jolanta Baranowska

Materials 2025, 18(6), 1331; https://doi.org/10.3390/ma18061331 - 18 Mar 2025

Abstract

The electron screening effect is responsible for a significant increase in the nuclear reaction rates in metals at very low energies. This is dependent on the local crystal structure of the metallic target and the occurrence of defects or additional elemental impurities in [...] Read more.

The electron screening effect is responsible for a significant increase in the nuclear reaction rates in metals at very low energies. This is dependent on the local crystal structure of the metallic target and the occurrence of defects or additional elemental impurities in the crystal. Here, we studied the deuteron–deuteron fusion reactions on zirconium targets previously implanted with carbon and oxygen ions. The ²H(d,p)³H reaction yield was measured at two deuteron energies, 8 and 20 keV, in order to determine the strength of the electron screening effect and its dependence on the density of the implanted impurities. We found that carbon implantation strongly reduced the experimentally determined screening energy, while oxygen implantation had the opposite effect. These results are especially important for the application of nuclear fusion in metallic environments at very low energies. Full article

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20 pages, 3279 KiB

Open AccessArticle

Efficient Ultrasound-Assisted Synthesis of Chemically Supported Anionic Functional Group Ionic Liquids and Its Enhanced Adsorption Performance Towards Vanadium (V)

by Bo Chen, Shenxu Bao, Yimin Zhang, Jiahao Zhou, Wei Ding, Liuyi Ren, Siyuan Yang and Ye Zhang

Materials 2025, 18(6), 1330; https://doi.org/10.3390/ma18061330 - 18 Mar 2025

Abstract

In this study, the chemically supported ionic liquids (CSILs) were synthesized by ultrasound irradiation (UI) to improve the preparation process and further strengthen the adsorption performance of CSILs towards vanadium (V). The impacts of UI and conventional mechanic stirring (CMS) on the synthesis [...] Read more.

In this study, the chemically supported ionic liquids (CSILs) were synthesized by ultrasound irradiation (UI) to improve the preparation process and further strengthen the adsorption performance of CSILs towards vanadium (V). The impacts of UI and conventional mechanic stirring (CMS) on the synthesis and adsorption characteristics of polystyrene [1-butyl-3-methylimidazolium][nitrate] (PS[C₄mim][NO₃]) were comparatively investigated. The experimental results demonstrate that ultrasound can dramatically shorten the preparation time from 1920 min to 15 min, and HNO₃ dosage is reduced by 15.79%. Under the same adsorption conditions, the CSILs synthesized by UI achieve the maximal adsorption capacity towards vanadium (V) as 248.95 mg/g at 150 min, while the CSILs processed by CMS reach 223.90 mg/g at 105 min. Particularly, the adsorption capacity of CSILs synthesized by UI can be maintained as 96.42% of the initial value after 10 cycles of adsorption–desorption, while that of CSILs processed by CMS maintain as 94.87%. The adsorption isotherm and kinetics fitting demonstrate that vanadium (V) adsorption by two CSILs is dominated by chemisorption as a single molecular layer. Additionally, the adsorption reaction of vanadium (V) by these two CSILs are both endothermic, and entropy increases. Fourier transform infrared, scanning electron microscopy, and energy spectrometry analyses prove that PS[C₄mim][NO₃] is successfully prepared by UI and CMS methods, and ultrasound waves will not destroy the intact spherical structure of the support resins. The current work provides a novel insight for the efficient synthesis of CSILs, which is also a potential technique for improving the adsorption performance of the adsorbents towards valuable metals. Full article

(This article belongs to the Special Issue Environmentally Friendly Adsorption Materials (2nd Edition))

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14 pages, 2548 KiB

Open AccessArticle

In-Situ One-Step Hydrothermal Synthesis of LiTi₂(PO₄)₃@rGO Anode for High Performance Lithium-Ion Batteries

by Otmane Zoubir, Abdelfettah Lallaoui, M’hamed Oubla, Alvaro Y. Tesio, Alvaro Caballero and Zineb Edfouf

Materials 2025, 18(6), 1329; https://doi.org/10.3390/ma18061329 - 17 Mar 2025

Abstract

The sodium super ionic conductor (NASICON) structured LiTi₂(PO₄)₃ (LTP) has been developed as electrode material for Li-ion batteries (LIBs) with promising electrochemical performance, owing to its outstanding structural stability and rapid lithium-ion diffusion. Nevertheless, challenges still exist, especially [...] Read more.

The sodium super ionic conductor (NASICON) structured LiTi₂(PO₄)₃ (LTP) has been developed as electrode material for Li-ion batteries (LIBs) with promising electrochemical performance, owing to its outstanding structural stability and rapid lithium-ion diffusion. Nevertheless, challenges still exist, especially the rapid capacity fading caused by the low electronic conductivity of LTP-NASICON material. Recently, the hydrothermal method has emerged as an important technique for the production of diverse nano-electrode materials due to its low preparation temperature, high phase purity, and well-controlled morphology and crystallinity. Herein, we report, for the first time at low-moderate temperatures, an advanced hydrothermal synthesis of LTP-coated reduced graphene oxide (LTP@rGO) particles that includes the growth of LTP particles while simultaneously coating them with rGO material. The LTP offers a discharge specific capacity of 84 mAh/g, while the LTP@rGO delivers a discharge capacity of 147 mAh/g, both with a coulombic efficiency of 99.5% after 100 cycles at a 1C rate. Full article

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21 pages, 14415 KiB

Open AccessArticle

Corrosion Resistance of Mn-Containing AFA Alloys in LBE at 550 °C with Controlled Oxygen Concentration of 10⁻⁶ wt.%

by Menghe Tu, Yajie He, Zihui Liu, Xiaogang Fu and Lingzhi Chen

Materials 2025, 18(6), 1328; https://doi.org/10.3390/ma18061328 - 17 Mar 2025

Abstract

Alumina-forming austenitic steels (AFA steels) exhibit excellent creep resistance and oxidation capabilities, making them a strong candidate for cladding materials in lead-cooled fast reactors. This study investigates the corrosion resistance of Mn-containing AFA steels in lead–bismuth eutectic (LBE) at 550 °C with a [...] Read more.

Alumina-forming austenitic steels (AFA steels) exhibit excellent creep resistance and oxidation capabilities, making them a strong candidate for cladding materials in lead-cooled fast reactors. This study investigates the corrosion resistance of Mn-containing AFA steels in lead–bismuth eutectic (LBE) at 550 °C with a controlled oxygen concentration of 10⁻⁶ wt.%. The results demonstrate that under these experimental conditions, the addition of Al enhances the material’s resistance to lead–bismuth corrosion. Moreover, Mn incorporation significantly improves corrosion resistance, with the optimal composition being an AFA alloy containing 16 wt.% Ni, 12 wt.% Cr, 3 wt.% Al, and 4 wt.% Mn. Mn addition alters the type of oxide product formed on the alloy surface, shifting from Fe₃O₄ or (Fe, Cr)_xO_y to (Cr, Mn)_xO_y. Full article

(This article belongs to the Section Corrosion)

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