Magnetochemistry

31 pages, 12185 KB

Open AccessArticle

Artificial Neural Network-Based Heat Transfer Analysis of Sutterby Magnetohydrodynamic Nanofluid with Microorganism Effects

by Fateh Ali, Mujahid Islam, Farooq Ahmad, Muhammad Usman and Sana Ullah Asif

Magnetochemistry 2025, 11(10), 88; https://doi.org/10.3390/magnetochemistry11100088 - 10 Oct 2025

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Abstract

Background: The study of non-Newtonian fluids in thin channels is crucial for advancing technologies in microfluidic systems and targeted industrial coating processes. Nanofluids, which exhibit enhanced thermal properties, are of particular interest. This paper investigates the complex flow and heat transfer characteristics of [...] Read more.

Background: The study of non-Newtonian fluids in thin channels is crucial for advancing technologies in microfluidic systems and targeted industrial coating processes. Nanofluids, which exhibit enhanced thermal properties, are of particular interest. This paper investigates the complex flow and heat transfer characteristics of a Sutterby nanofluid (SNF) within a thin channel, considering the combined effects of magnetohydrodynamics (MHD), Brownian motion, and bioconvection of microorganisms. Analyzing such systems is essential for optimizing design and performance in relevant engineering applications. Method: The governing non-linear partial differential equations (PDEs) for the flow, heat, concentration, and bioconvection are derived. Using lubrication theory and appropriate dimensionless variables, this system of PDEs is simplified into a more simplified system of ordinary differential equations (ODEs). The resulting nonlinear ODEs are solved numerically using the boundary value problem (BVP) Midrich method in Maple software to ensure accuracy. Furthermore, data for the Nusselt number, extracted from the numerical solutions, are used to train an artificial neural network (ANN) model based on the Levenberg–Marquardt algorithm. The performance and predictive capability of this ANN model are rigorously evaluated to confirm its robustness for capturing the system’s non-linear behavior. Results: The numerical solutions are analyzed to understand the variations in velocity, temperature, concentration, and microorganism profiles under the influence of various physical parameters. The results demonstrate that the non-Newtonian rheology of the Sutterby nanofluid is significantly influenced by Brownian motion, thermophoresis, bioconvection parameters, and magnetic field effects. The developed ANN model demonstrates strong predictive capability for the Nusselt number, validating its use for this complex system. These findings provide valuable insights for the design and optimization of microfluidic devices and specialized coating applications in industrial engineering. Full article

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3 pages, 158 KB

Open AccessEditorial

Advances in Soft Magnetic Materials

by Kaixuan Li and Zhaoyang Wu

Magnetochemistry 2025, 11(10), 87; https://doi.org/10.3390/magnetochemistry11100087 - 9 Oct 2025

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Abstract

Soft magnetic materials have emerged as promising candidates due to their high power density in diverse magnetic components utilized for energy conversion, filtering, resonance, and isolation [...] Full article

(This article belongs to the Special Issue Advances in Soft Magnetic Materials)

17 pages, 6479 KB

Open AccessArticle

Structural Color and Mueller Matrix Analysis in a Ferrocell

by Alberto Tufaile and Adriana Pedrosa Biscaia Tufaile

Magnetochemistry 2025, 11(10), 86; https://doi.org/10.3390/magnetochemistry11100086 - 29 Sep 2025

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Abstract

This study investigates the magneto-optical properties of a ferrofluid using an accessible Ferrocell device. Our findings demonstrate that the ferrofluid’s behavior is critically dependent on its concentration. At high concentrations, the medium is optically dense, with inter-particle scattering and absorption dominating, which prevents [...] Read more.

This study investigates the magneto-optical properties of a ferrofluid using an accessible Ferrocell device. Our findings demonstrate that the ferrofluid’s behavior is critically dependent on its concentration. At high concentrations, the medium is optically dense, with inter-particle scattering and absorption dominating, which prevents the formation of clear light patterns. However, with intermediate dilution, the system enters a “pattern formation zone” where the magnetic field effectively aligns the nanoparticles, creating complex, visible light patterns like horocycles. The appearance of these patterns provides evidence of field-induced ordering and structural coloration. The colors observed are not due to pigments, but result from the interaction of light with the periodic structures formed by the aligned nanoparticles. Our analysis, supported by the Mueller matrix framework, confirms that the ferrofluid acts as a retarder. The birefringence induced by the magnetic field varies across the film, leading to a chromatic dispersion that selectively suppresses certain wavelengths. This process explains how a specific color, such as blue, can be blocked at one location while others pass through, creating structural colors observed in the patterns. Full article

(This article belongs to the Special Issue Ferrofluids: Electromagnetic Properties and Applications)

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20 pages, 6572 KB

Open AccessArticle

pH and Magnetic-Responsive Carboxymethyl Chitosan/Sodium Alginate Composites for Gallic Acid Delivery

by Kun Fang, Pei Li, Hanbing Wang, Xiangrui Huang and Yihan Li

Magnetochemistry 2025, 11(10), 85; https://doi.org/10.3390/magnetochemistry11100085 - 28 Sep 2025

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Abstract

Gallic acid (GA) exhibits a broad range of biological activities; however, its clinical application is significantly limited by poor stability, rapid degradation, and low bioavailability. Consequently, developing responsive delivery platforms to enhance GA stability and targeted release has become an important research focus. [...] Read more.

Gallic acid (GA) exhibits a broad range of biological activities; however, its clinical application is significantly limited by poor stability, rapid degradation, and low bioavailability. Consequently, developing responsive delivery platforms to enhance GA stability and targeted release has become an important research focus. Herein, GA was encapsulated within novel composite hydrogel beads (CMC-SA-Fe₃O₄@GA) prepared via crosslinking carboxymethyl chitosan (CMC) and sodium alginate (SA) with Fe₃O₄ nanoparticles (NPs) to facilitate efficient drug delivery. The formulation was characterized and evaluated in terms of drug-loading capacity, controlled-release properties, antioxidant activity, antibacterial performance, and biocompatibility. The results indicated that the GA loading efficiency reached 31.07 ± 1.23%. Application of an external magnetic field accelerated GA release, with the observed release kinetics fitting the Ritger–Peppas model. Furthermore, antioxidant capacity, evaluated by DPPH assays, demonstrated excellent antioxidant activity of the CMC-SA-Fe₃O₄@GA composite beads. Antibacterial tests confirmed sustained inhibitory effects against Escherichia coli and Staphylococcus aureus. In vitro, cellular assays indicated favorable biocompatibility with normal hepatic cells (HL-7702) and effective inhibition of hepatocellular carcinoma cells (HepG2). Overall, the novel pH- and magnetic field-responsive CMC-SA-Fe₃O₄@GA hydrogel system developed in this work offers considerable potential for controlled delivery of phenolic compounds, demonstrating promising applicability in biomedical and food-related fields. Full article

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17 pages, 4644 KB

Open AccessArticle

Study of the Magnetohydrodynamic Instability and a New Suppression Method in Liquid Metal Batteries

by Jia-Jun Song, Xiao-Zhong Zuo, En-Qi Zhu, Qi-Guang Li, Bao-Zhi Chen and Ben-Wen Li

Magnetochemistry 2025, 11(10), 84; https://doi.org/10.3390/magnetochemistry11100084 - 25 Sep 2025

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Abstract

As a strong candidate for energy storage applications, Liquid Metal Batteries (LMBs) have the advantages of higher current density, longer cycle life, and simpler manufacturing of large-scale storage systems. Owing to the all-liquid construction, various kinds of Magnetohydrodynamic instabilities (MHDIs) are present in [...] Read more.

As a strong candidate for energy storage applications, Liquid Metal Batteries (LMBs) have the advantages of higher current density, longer cycle life, and simpler manufacturing of large-scale storage systems. Owing to the all-liquid construction, various kinds of Magnetohydrodynamic instabilities (MHDIs) are present in LMBs. In this paper, an in-depth study of the evolution process of MHDIs within LMBs has been conducted. By analyzing the characteristic velocity, the growth rate of instabilities γ has been defined so that the critical Hartmann number at which the instability occurs can be ascertained. A new critical parameter, mixed Reynolds number Re_mix, has been introduced to determine the duration of stable battery operation across varying charging/discharging currents, including those that may surpass the prescribed safe limits. Finally, a method for mitigating magnetohydrodynamic instability in LMBs through the configuration of busbar current is proposed, which can be seamlessly integrated with parallel battery packs. A comparative analysis of LMBs operation with/without bus current configuration reveals that when bus current is appropriately configured, the magnetic field strength within the battery undergoes a notable reduction of 40%, leading to a significant suppression of instability. The conclusions offer theoretical underpinnings for the application of LMBs in large-scale grid-level energy storage systems. Full article

(This article belongs to the Section Magnetic Field)

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21 pages, 6518 KB

Open AccessArticle

Topological Rainbow Trapping in One-Dimensional Magnetoelastic Phononic Crystal Slabs

by Wen Xiao, Fuhao Sui, Jiujiu Chen, Hongbo Huang and Tao Luo

Magnetochemistry 2025, 11(10), 83; https://doi.org/10.3390/magnetochemistry11100083 - 25 Sep 2025

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Abstract

We design a one-dimensional magnetoelastic phononic crystal slab composed of the smart magnetostrictive material Terfenol-D and pure tungsten. Band inversion and topological phase transitions are achieved by modifying the geometric parameters of the non-magnetic medium within the unit cell. The emergence of topological [...] Read more.

We design a one-dimensional magnetoelastic phononic crystal slab composed of the smart magnetostrictive material Terfenol-D and pure tungsten. Band inversion and topological phase transitions are achieved by modifying the geometric parameters of the non-magnetic medium within the unit cell. The emergence of topological interface states within overlapping bandgaps, exhibiting distinct topological properties, along with their robustness against interfacial structural defects, is confirmed. The coupling effects between adjacent topological interface states in a sandwich-like supercell configuration are investigated, and their tunability under external magnetic fields is demonstrated. A Su-Schrieffer-Heeger (SSH) phononic crystal slab system under gradient magnetic fields is proposed. Critically, and in stark contrast to previous static or structurally graded designs, we achieve reconfigurable rainbow trapping of topological interface states solely by reprogramming the gradient magnetic field, leaving the physical structure entirely unchanged. This highly localized, compact, and broadband-tunable topological rainbow trapping system design holds significant promise for applications in elastic energy harvesting, wave filtering, and multi-frequency signal processing. Full article

(This article belongs to the Special Issue Advances in Low-Dimensional Magnetic Materials)

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25 pages, 4694 KB

Open AccessReview

Magnetic-Responsive Material-Mediated Magnetic Stimulation for Tissue Engineering

by Jiayu Gu, Lijuan Gui, Dixin Yan, Xunrong Xia, Zhuoli Xie and Le Xue

Magnetochemistry 2025, 11(10), 82; https://doi.org/10.3390/magnetochemistry11100082 - 23 Sep 2025

Viewed by 597

Abstract

Tissue repair is a significant challenge in biomedical research. Traditional treatments face limitations such as donor shortage, high costs, and immune rejection. Recently, magnetic-responsive materials, particularly magnetic nanoparticles have been introduced into tissue engineering due to their ability to respond to external magnetic [...] Read more.

Tissue repair is a significant challenge in biomedical research. Traditional treatments face limitations such as donor shortage, high costs, and immune rejection. Recently, magnetic-responsive materials, particularly magnetic nanoparticles have been introduced into tissue engineering due to their ability to respond to external magnetic fields, generating electrical, thermal, and mechanical effects. These effects enable precise regulation of cellular behavior and promote tissue regeneration. Compared to traditional physical stimulation, magnetic-responsive material-mediated stimulation offers advantages such as non-invasiveness, deep tissue penetration, and high spatiotemporal precision. This review summarizes the classification, fabrication, magnetic effects and applications of magnetic-responsive materials, focusing on their mechanisms and therapeutic effects in neural and bone tissue engineering, and discusses future directions. Full article

(This article belongs to the Section Applications of Magnetism and Magnetic Materials)

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Magnetochemistry, Volume 11, Issue 10 (October 2025) – 7 articles

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