Materials

22 pages, 4595 KiB

Open AccessArticle

Dynamic Stability Enhancement of Columns Through Material Distribution Optimization Strategies

by Janusz Szmidla, Anna Jurczyńska and Robert Ulewicz

Materials 2025, 18(10), 2167; https://doi.org/10.3390/ma18102167 (registering DOI) - 8 May 2025

This study focuses on optimizing the shape of columns, particularly considering advanced material distributions that respond to specific load cases. Utilizing a variational method, equations describing movement and boundary conditions are established. This research, while adhering to a static and kinetic criterion for stability loss, identifies the optimal geometric parameters for the columns constructed from specific materials to achieve maximum critical load capacity. It is assumed that the total volume of the system does not change. The innovation of the presented research is the use of a simulated annealing algorithm to optimally shape the column outline in terms of the maximum critical force value, which depends on many material variables. This method was adapted to the calculations of slender rod systems by introducing a number of modifications. The obtained increases in the critical load reach up to 40% compared to the prismatic system. The results also show that it is possible to control the dynamic properties in column structures while increasing the stability of the system. This study underscores the significant role of material selection and optimization in enhancing the dynamic stability and load-bearing capacity of column structures. Full article

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14 pages, 4092 KiB

Open AccessArticle

Preparation of V₂O₅ Composite Cathode Material Based on In Situ Intercalated Polyaniline and Its High-Performance Aqueous Zinc-Ion Battery Applications

by Shilin Li, Taoyun Zhou, Yun Cheng and Xinyu Li

Materials 2025, 18(10), 2166; https://doi.org/10.3390/ma18102166 (registering DOI) - 8 May 2025

Abstract

With the rapid growth of renewable energy, the need for efficient and stable energy storage systems has become increasingly urgent. Aqueous zinc-ion batteries (AZIBs) can offer high safety, abundant zinc supply, and promising electrochemical properties. However, their performance is limited by poor electronic conductivity, slow Zn²⁺ diffusion, and structural degradation of conventional cathode materials. To address these issues, an in situ polyaniline (PANI) intercalation strategy for vanadium oxide cathodes is introduced in this paper. The conductive PANI chains play three key roles: (1) expand and stabilize interlayer spacing, (2) enhance electronic conductivity, and (3) provide mechanical support to prevent structural collapse and zinc-dendrite formation. A flower-like PANI-V₂O₅ hybrid is synthesized via synchronous oxidative polymerization, forming a hierarchical architecture without inert intercalants. The resulting electrode achieves a high specific capacity of 450 mAh·g⁻¹ at 0.1 A·g⁻¹ and retains 96.7% of its capacity after 300 cycles at 1 A·g⁻¹, with excellent rate performance. These findings demonstrate that PANI intercalation enhances ion transport, electronic conductivity, and structural integrity, offering a promising design approach for next-generation AZIBs cathodes. Full article

(This article belongs to the Special Issue Methodologies and Mechanisms in Facet Engineering for Next-Generation Ion Batteries)

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23 pages, 5161 KiB

Open AccessArticle

Correlating the Effects of UV Aging on the Macro-Micro Behaviors of Asphalt with Its Molecular Mechanisms

by Han Xi, Lingyun Kong, Shixiong Hu and Songxiang Zhu

Materials 2025, 18(10), 2165; https://doi.org/10.3390/ma18102165 (registering DOI) - 8 May 2025

Abstract

UV radiation can change the internal molecular composition, macroscopic rheological properties, and microscopic chemical composition of asphalt. To study the effect of ultraviolet aging on asphalt and its structure–activity relationship, its rheological properties were measured by dynamic shear rheology and multiple stress recovery creep tests, its chemical compositions were measured by component composition, elemental composition, and infrared spectrum tests, and its molecular weight, distribution, and molecular structure were determined by gel permeation chromatography and nuclear magnetic resonance tests. Then, the molecular weight and molecular structure, rheological properties, and microchemical aging behavior of asphalt after UV aging were characterized by correlation analysis, and the structure–activity relationship was analyzed. The results show that the deformation resistance and elastic recovery ability of asphalt after UV aging are enhanced, and the flow performance is decreased. The ultraviolet radiation caused the aromatic hydrocarbons containing naphthenes and long alkyl chains in the asphalt to break and connect with asphaltenes with a ring structure. The asphaltene content in each bitumen sample exceeded 46%, and that in KL reached 55%, indicating that the bitumen changed into a gel structure. UV aging causes the aggregation of asphalt molecules, and the aggregation of molecules narrows the molecular distribution boundary and moves in the direction of macromolecules, resulting in the reduction of the dispersion coefficient by 2–10%. Hydrogen atoms will undergo condensation and substitution reactions due to long-chain breaking, cyclization, or aromatization under UV action, and the breaking of C=C bonds in carbon atoms will increase the stable aromatic ring, strengthen the stiffness of the molecular backbone, and make it difficult for the backbone to spin. Through correlation analysis, it was found that the molecular composition index could characterize the aging behavior index of asphalt, and that the aromatic structure was the most critical molecular change. Further, it was found that the sulfoxide group and carbonyl group could be used as evaluation criteria for the UV aging of asphalt because the correlation between them was above 0.7. This study provides an essential index reference for evaluating the performance change of asphalt under ultraviolet aging to save testing time. Moreover, the molecular structure characterization revealed the changes in internal molecular composition that were behind the observed aging properties, providing a theoretical basis for research on asphalt anti-aging technology. Full article

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

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Materials, Volume 18, Issue 10 (May-2 2025) – 3 articles

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