TY - GEN A1 - Glavan, Gašper A1 - Belyaeva, Inna A. A1 - Shamonin (Chamonine), Mikhail T1 - Transient Response of Macroscopic Deformation of Magnetoactive Elastomeric Cylinders in Uniform Magnetic Fields [Data set] Y1 - 2024 U6 - https://doi.org/10.5281/zenodo.10679499 N1 - This is the data set for all the figures in the paper with the title: "Transient Response of Macroscopic Deformation of Magnetoactive Elastomeric Cylinders in Uniform Magnetic Fields" published in the Polymers journal (doi:10.3390/polym16050586). ER - TY - GEN A1 - Glavan, Gašper A1 - Belyaeva, Inna A. A1 - Shamonin (Chamonine), Mikhail A1 - Ruwisch, Kevin A1 - Wollschläger, Joachim T1 - Magnetoelectric Response of Laminated Cantilevers Comprising a Magnetoactive Elastomer and a Piezoelectric Polymer, in Pulsed Uniform Magnetic Fields [Data set] Y1 - 2025 U6 - https://doi.org/10.5281/zenodo.14652152 N1 - This is the data set for all the figures in the paper with the title: "Magnetoelectric Response of Laminated Cantilevers Comprising a Magnetoactive Elastomer and a Piezoelectric Polymer, in Pulsed Uniform Magnetic Fields" published in the Sensors journal (doi:10.3390/s21196390). ER - TY - GEN A1 - Glavan, Gašper A1 - Belyaeva, Inna A. A1 - Shamonin (Chamonine), Mikhail T1 - On the Piezomagnetism of Magnetoactive Elastomeric Cylinders in Uniform Magnetic Fields: Height Modulation in the Vicinity of an Operating Point by Time-Harmonic Fields [Data set] Y1 - 2024 U6 - https://doi.org/10.5281/zenodo.13834054 N1 - This is the data set for all the figures in the paper with the title: "On the Piezomagnetism of Magnetoactive Elastomeric Cylinders in Uniform Magnetic Fields: Height Modulation in the Vicinity of an Operating Point by Time-Harmonic Fields" published in the Polymers journal (doi:10.3390/polym16192706). ER - TY - GEN A1 - Glavan, Gašper A1 - Belyaeva, Inna A. A1 - Shamonin (Chamonine), Mikhail T1 - Multiferroic Cantilevers Containing a Magnetoactive Elastomer: Magnetoelectric Response to Low-Frequency Magnetic Fields of Triangular and Sinusoidal Waveform [Data set] Y1 - 2025 U6 - https://doi.org/10.5281/zenodo.14651784 N1 - This is the data set for all the figures in the paper with the title: "Multiferroic Cantilevers Containing a Magnetoactive Elastomer: Magnetoelectric Response to Low-Frequency Magnetic Fields of Triangular and Sinusoidal Waveform" published in the Sensor journal (doi:10.3390/s22103791). ER - TY - JOUR A1 - Straus, Izidor A1 - Kravanja, Gaia A1 - Kriegl, Raphael A1 - Shamonin (Chamonine), Mikhail A1 - Drevenšek-Olenik, Irena A1 - Jezeršek, Matija A1 - Kokot, Gašper T1 - Laser Micromachining for Polymer Surface Topography Designt JF - JoVE journal : engineering N2 - Soft magnetoactive elastomers (MAEs) are smart materials that respond to external magnetic fields by dynamically altering their mechanical properties. They are composed of magnetically responsive microparticles embedded within a soft polymer matrix, exhibiting an effective shear modulus of up to 100 kPa. In recent decades, MAEs' bulk properties have been successfully exploited for applications such as dynamic vibration damping, vibration sensing, and actuation in soft robotics. Recent research has shifted to their surface properties, revealing promising results on tunable surface features such as roughness, adhesion, and wetting. Even the transport of small solid and fluid objects was demonstrated. The associated surface effects can be significantly enhanced through the precise engineering of surface topography. In this article, an efficient laser micromachining technique, with a resolution of 15 µm, is presented, which enables rapid prototyping of MAE surfaces. It allows the creation of various complex shapes and offers functionality beyond the one achievable with traditional molding techniques. Additionally, the approach is versatile and can be applied to any polymer that sufficiently absorbs the laser light. As an example, a lamellar surface micro-pattern fabrication process and its characterization by optical and scanning electron microscopies are shown. Its response to a magnetic field is demonstrated. The technique provides a flexible and fast solution for optimizing polymer surface design across a wide range of applications. Y1 - 2025 U6 - https://doi.org/10.3791/68126 PB - JoVE ER - TY - JOUR A1 - Roghani, Mehran A1 - Romeis, Dirk A1 - Glavan, Gašper A1 - Belyaeva, Inna A. A1 - Shamonin (Chamonine), Mikhail A1 - Saphiannikova, Marina T1 - Magnetically induced deformation of isotropic magnetoactive elastomers and its relation to the magnetorheological effect JF - Physical Review Applied N2 - Can isotropic magnetoactive elastomers (MAEs) undergo giant magnetically induced deformations and exhibit huge magnetorheological effects simultaneously? In this experimental and theoretical study, we reveal how the macroscopic deformation of MAEs relates to the process of particle restructuring caused by application of a magnetic field. For this purpose, MAE cylinders with different aspect ratios and particle loadings are studied in uniform magnetic fields. The axial deformations of the cylinders are acquired using an optical camera. A unified mean-field model proposed in previous studies is adapted to describe the transition of initially isotropic cylinders into transversely isotropic ones. This mechanical transition is caused by the rearrangement of particles into dense columnar structures aligned with the field and is believed to result in a huge magnetorheological effect. Our model however predicts less than a threefold increase in elastic moduli when evaluated along the field direction. This prediction is based on a careful examination of the shear moduli of studied MAEs and the columnar structures. A weak magnetorheological effect explains significant axial deformations measured in the field direction. A strong magnetorheological effect would hinder axial deformations due to an increase in the modulus by several orders of magnitude. Not only are the moduli and macroscopic deformations influenced by microstructure evolution, but so is the magnetization of particles, which increases as they rearrange into dense columns. With this study, we show that the unified mean-field model provides quantitative access to hidden material properties such as magnetization and stiffness in MAE samples with different shapes and evolving microstructures. Published by the American Physical Society 2025 Y1 - 2025 U6 - https://doi.org/10.1103/PhysRevApplied.23.034041 SN - 2331-7019 VL - 23 IS - 3 PB - American Physical Society (APS) ER - TY - JOUR A1 - Kriegl, Raphael A1 - Krenkel, Lars A1 - Shamonin (Chamonine), Mikhail T1 - Preservation of wetting ridges using field-induced plasticity of magnetoactive elastomers JF - Journal of Colloid and Interface Science N2 - Hypothesis. The presence of a wetting ridge is crucial for many wetting phenomena on soft substrates. Conventional experimental observations of a wetting ridge require permanent presence of a droplet. The magnetic field-induced plasticity effect (FIPE) of soft magnetoative elastomers (MAEs) allows one to overcome this limitation. Depositing a droplet onto an MAE surface and applying a magnetic field fixes the wetting ridge in place due to the FIPE. The droplet can be removed to investigate the ridge with ease using conventional optical methods. Experiments. The wetting ridge is observed on MAEs with different shear moduli and different material thicknesses by confocal laser scanning microscopy (LSM). The preservation quality of the ridge is analyzed for several values of magnetic field from 10 mT to 270 mT. To verify the plausibilty of results obtained, the measured shape is compared to a theoretical model by Style & Dufresne. Findings. Upon removal of the sessile droplet, the deformation remains embossed onto the MAE surface as long as the magnetic field remains applied. The height of the ridge peak on soft samples (effective shear modulus kPa) is close to the theoretical prediction for a magnetic flux density of 50 mT. The magnitude of the external magnetic field magnifies the height of the wetting ridge. KW - Wetting ridge KW - Droplet KW - Magnetoactive elastomer KW - Magnetorheological elastomer KW - Field-induced plasticity KW - Confocal laser scanning microscopy Y1 - 2025 U6 - https://doi.org/10.1016/j.jcis.2024.12.132 SN - 0021-9797 N1 - Corresponding author der OTH Regensburg: Raphael Kriegl VL - 683 SP - 1019 EP - 1027 PB - Elsevier ER - TY - CHAP A1 - Kriegl, Raphael A1 - Jezeršek, Matija A1 - Kravanja, Gaia A1 - Hribar, Luka A1 - Kokot, Gašper A1 - Drevenšek‐Olenik, Irena A1 - Shamonin (Chamonine), Mikhail T1 - Characterization of Tunable Rebound Properties of Microstructured Magnetoactive Elastomers T2 - ASME 2024 Conference on Smart Materials, Adaptive Structures and Intelligent Systems (SMASIS), September 9–11, 2024, Atlanta, Georgia, USA N2 - We present a novel method to control the rebounding behavior of small mm-sized solid balls by employing magnetoactive elastomers (MAEs) with microstructured surfaces. An MAE is a composite material consisting of μm-sized ferromagnetic particles dispersed in a soft elastomer (e.g., polydimethylsiloxane) matrix. In the act of rebounding, the ball hits an MAE surface and bounces back. The MAE samples contained 75 wt.% of iron. This composite material is known to respond to an applied magnetic field with increased stiffness (due to the magnetorheological effect) and plasticity. To adjust the rebound properties, the top layer of the MAE material was additionally modified by micromachining lamellar structures with different dimensions on the 100 μm scale via laser ablation. Due to the resulting high aspect ratio, these surface structures were sensitive to the magnetic field direction. The lamellas could stand up straight or lay down flat. The rebound behavior was evaluated by using a custom build apparatus that facilitates dropping of the balls in a precise and repeatable manner. A ball was dropped from different heights. The ball trajectory was captured with a high-speed camera to investigate the rebound properties. The recorded video was processed using a custom software written in Python. The experimental procedure and data processing algorithms are presented in detail. The results for the samples with different geometrical dimensions are provided as examples. It is made evident that the magnetic field influences the rebound properties of small non-magnetic balls impinging microstructured MAE surfaces. The change in surface topography is an effective way to control the ball rebound. The fabrication flexibility in geometrical dimensions of surface microstructures opens a convenient way to tune the desired response to magnetic fields. The presented idea may find applications in impact mitigation or small-scale sorting machinery, e.g. for recycling. Y1 - 2024 SN - 978-0-7918-8832-2 U6 - https://doi.org/10.1115/SMASIS2024-139154 PB - American Society of Mechanical Engineers CY - New York, USA ER - TY - JOUR A1 - Glavan, Gašper A1 - Belyaeva, Inna A. A1 - Shamonin (Chamonine), Mikhail T1 - On the Piezomagnetism of Magnetoactive Elastomeric Cylinders in Uniform Magnetic Fields: Height Modulation in the Vicinity of an Operating Point by Time-Harmonic Fields JF - Polymers N2 - Soft magnetoactive elastomers (MAEs) are currently considered to be promising materials for actuators in soft robotics. Magnetically controlled actuators often operate in the vicinity of a bias point. Their dynamic properties can be characterized by the piezomagnetic strain coefficient, which is a ratio of the time-harmonic strain amplitude to the corresponding magnetic field strength. Herein, the dynamic strain response of a family of MAE cylinders to the time-harmonic (frequency of 0.1-2.5 Hz) magnetic fields of varying amplitude (12.5 kA/m-62.5 kA/m), superimposed on different bias magnetic fields (25-127 kA/m), is systematically investigated for the first time. Strain measurements are based on optical imaging with sub-pixel resolution. It is found that the dynamic strain response of MAEs is considerably different from that in conventional magnetostrictive polymer composites (MPCs), and it cannot be described by the effective piezomagnetic constant from the quasi-static measurements. The obtained maximum values of the piezomagnetic strain coefficient (∼102 nm/A) are one to two orders of magnitude higher than in conventional MPCs, but there is a significant phase lag (35-60°) in the magnetostrictive response with respect to an alternating magnetic field. The experimental dependencies of the characteristics of the alternating strain on the amplitude of the alternating field, bias field, oscillation frequency, and aspect ratio of cylinders are given for several representative examples. It is hypothesized that the main cause of observed peculiarities is the non-linear viscoelasticity of these composite materials. Y1 - 2024 U6 - https://doi.org/10.3390/polym16192706 N1 - Corresponding author der OTH Regensburg: Gašper Glavan VL - 16 IS - 19 ER - TY - JOUR A1 - Savelev, Dmitrii V. A1 - Glavan, Gašper A1 - Burdin, Dmitrii A. A1 - Belyaeva, Inna A. A1 - Fetisov, Leonid Y. A1 - Shamonin (Chamonine), Mikhail A1 - Fetisov, Yuri K. T1 - Enhancement of magnetoelectric effect in polymer composites at low resonance frequencies by operation in the transverse-transverse mode JF - Journal of Magnetism and Magnetic Materials N2 - The resonant direct magnetoelectric (ME) effect for a series of multilayer heterostructures comprising a magnetoactive elastomer (MAE) of different thicknesses and a commercially available piezoelectric polyvinylidene fluoride-based vibration sensor has been investigated in detail. The specimens were rigidly fixed at one end as cantilevers. The cantilevers were operated in the transverse-transverse (T-T) mode, where both magnetic and electric fields were perpendicular to the plane of a non-deformed heterostructure. It is shown that the ME voltage coefficient of considered heterostructures in the T-T mode can be about 20-fold higher than in the conventional longitudinal–transverse (L-T) mode. The highest ME voltage coefficient reached about 150 V/(Oe·cm) at the first bending oscillation mode for the sample with MAE layer thickness of 4 mm. Mechanism of the resonant ME effect in T-T mode is explained using theory of critical bending of MAE cantilevers. Magnetic fields, when the ME voltage reaches its maximum, strongly depended on the MAE layer thickness, and could be associated with the critical field, where the structure commences to strongly bend. The non-monotonous dependence of the resonance frequency of the first oscillation mode on magnetic field strength was observed. The shift of the resonance frequency in the maximum magnetic field reached up to roughly 100 % in comparison with zero field. KW - Direct magnetoelectric effect KW - Magnetoactive elastomer KW - Piezoelectric polymer KW - Flexible composite KW - Low resonance frequency KW - Multilayer heterostructure Y1 - 2024 U6 - https://doi.org/10.1016/j.jmmm.2024.172020 SN - 1873-4766 SN - 0304-8853 VL - 598 PB - Elsevier ER - TY - JOUR A1 - Straus, Izidor A1 - Kravanja, Gaia A1 - Hribar, Luka A1 - Kriegl, Raphael A1 - Jezeršek, Matija A1 - Shamonin (Chamonine), Mikhail A1 - Drevenšek‐Olenik, Irena A1 - Kokot, Gašper T1 - Surface Modification of Magnetoactive Elastomers by Laser Micromachining JF - Materials N2 - It has been recently demonstrated that laser micromachining of magnetoactive elastomers is a very convenient method for fabricating dynamic surface microstructures with magnetically tunable properties, such as wettability and surface reflectivity. In this study, we investigate the impact of the micromachining process on the fabricated material’s structural properties and its chemical composition. By employing scanning electron microscopy, we investigate changes in size distribution and spatial arrangement of carbonyl iron microparticles dispersed in the polydimethylsiloxane (PDMS) matrix as a function of laser irradiation. Based on the images obtained by a low vacuum secondary electron detector, we analyze modifications of the surface topography. The results show that most profound modifications occur during the low-exposure (8 J/cm^2) treatment of the surface with the laser beam. Our findings provide important insights for developing theoretical models of functional properties of laser-sculptured microstructures from magnetoactive elastomers. KW - magnetoactive elastomer KW - MAE KW - laser micromachining KW - particle distributions KW - SEM Y1 - 2024 U6 - https://doi.org/10.3390/ma17071550 N1 - This research was funded by the Slovenian Research Agency (ARRS): research programs P1-0192, P2-0392, and research project J1-3006. The work of R.K. and M.S. in Regensburg was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), project number 437391117. VL - 2024 IS - 17 / 7 PB - MDPI AG CY - Basel, Switzerland ER - TY - JOUR A1 - Kriegl, Raphael A1 - Jezeršek, Matija A1 - Kravanja, Gaia A1 - Hribar, Luka A1 - Mukhi, Soham A1 - Kokot, Gašper A1 - Drevenšek‐Olenik, Irena A1 - Shamonin (Chamonine), Mikhail T1 - Tunable rebound of millimeter-sized rigid balls by magnetic actuation of elastomer-based surface microstructures JF - Smart Materials and Structures N2 - A novel method for controlling the rebound behavior of small balls made of Al2O3 with a radius of 2.381 mm is presented. It uses different types of micro-structured surfaces of soft magnetoactive elastomers. These surfaces were fabricated via laser micromachining and include fully ablated surfaces as well as micrometer-sized lamellas with a fixed width of 90 µm, height of 250 µm and three different gap sizes (15, 60 and 105 µm). The lamellas can change their orientation from edge-on to face-on configuration according to the direction of the external magnetic field from a permanent magnet. The orientation of the external magnetic field significantly influences the rebound behavior of the balls, from a coefficient of restitution e of to < 0.1. The highest relative change in the coefficient of restitution between zero field and face-on configuration of is observed for lamellas with a gap of 60 µm. Other characteristics of the ball rebound such as the penetration depth into an Magnetoactive elastomer and the maximum deceleration are investigated as well. The proposed method does not require a constant power supply due to the use of permanent magnets. It may find novel applications in the field of impact engineering. Y1 - 2024 U6 - https://doi.org/10.1088/1361-665X/ad41a9 N1 - Zugehöriges Datenset: https://doi.org/10.5281/zenodo.10419411 VL - 33 IS - 6 PB - IOP Publishing ER - TY - JOUR A1 - Glavan, Gašper A1 - Belyaeva, Inna A. A1 - Shamonin (Chamonine), Mikhail T1 - Transient Response of Macroscopic Deformation of Magnetoactive Elastomeric Cylinders in Uniform Magnetic Fields JF - Polymers N2 - Significant deformations of bodies made from compliant magnetoactive elastomers (MAE) in magnetic fields make these materials promising for applications in magnetically controlled actuators for soft robotics. Reported experimental research in this context was devoted to the behaviour in the quasi-static magnetic field, but the transient dynamics are of great practical importance. This paper presents an experimental study of the transient response of apparent longitudinal and transverse strains of a family of isotropic and anisotropic MAE cylinders with six different aspect ratios in time-varying uniform magnetic fields. The time dependence of the magnetic field has a trapezoidal form, where the rate of both legs is varied between 52 and 757 kA/(s·m) and the maximum magnetic field takes three values between 153 and 505 kA/m. It is proposed to introduce four characteristic times: two for the delay of the transient response during increasing and decreasing magnetic field, as well as two for rise and fall times. To facilitate the comparison between different magnetic field rates, these characteristic times are further normalized on the rise time of the magnetic field ramp. The dependence of the normalized characteristic times on the aspect ratio, the magnetic field slew rate, maximum magnetic field values, initial internal structure (isotropic versus anisotropic specimens) and weight fraction of the soft-magnetic filler are obtained and discussed in detail. The normalized magnetostrictive hysteresis loop is introduced, and used to explain why the normalized delay times vary with changing experimental parameters. KW - magnetoactive elastomer KW - magnetorheological elastomer KW - macroscopic deformation KW - magnetostriction KW - time-varying magnetic field Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-71067 SN - 2073-4360 N1 - Corresponding author der OTH Regensburg: Gašper Glavan Zugehöriges Datenset: doi:10.5281/zenodo.10679499 VL - 16 IS - 5, Special Issue Magnetic Polymer Composites: Design and Application II PB - MDPI CY - Basel, Schweiz ER - TY - GEN A1 - Kriegl, Raphael A1 - Kravanja, Gaia A1 - Hribar, Luka A1 - Jezeršek, Matija A1 - Drevenšek‐Olenik, Irena A1 - Shamonin (Chamonine), Mikhail T1 - Characterization of Wetting Properties of Magnetoactive Elastomer Surfaces T2 - Proceedings of the ASME Conference on Smart Materials, Adaptive Structures and Intelligent Systems (SMASIS) - 2023, September 11–13, 2023 Austin, Texas, USA N2 - Commercially available contact angle (CA) measuring devices usually do not allow for the application of magnetic fields to the sample under test. A setup for measuring the CA of liquids on magnetosensitive surfaces has been developed specifically for investigating the surfaces of magnetoactive elastomers (MAEs). The addition of a programmable linear stage, which moves a permanent magnet, allows for fine control of the magnetic field applied to the MAE without the need for large and power-consuming electromagnets. Paired with a custom control and evaluation software, this measurement setup operates semiautomatically, limiting operator error and increasing precision, speed, as well as repeatability of static and dynamic CA measurements for different magnetoactive materials. The software is equipped with robust droplet fitting algorithms to avoid experimental challenges arising with soft magnetoactive materials, such as the curling of sample edges or diffuse non-reflective surfaces. Several application examples on MAE surfaces, both processed and unprocessed, are presented. KW - magnetoactive elastomers KW - image processing KW - droplet contour fitting KW - contact angle Y1 - 2023 SN - 978-0-7918-8752-3 U6 - https://doi.org/10.1115/SMASIS2023-110998 N1 - Corresponding author: Raphael Kriegl PB - The American Society of Mechanical Engineers CY - New York, USA ER - TY - JOUR A1 - Lohmeyer, Manfred A1 - Shamonin (Chamonine), Mikhail A1 - Hertel, Peter T1 - Integrated optical circulator based on radiatively coupled magneto-optic waveguides JF - Optical Engineering N2 - In a three-guide coupler with multimode central waveguide, more than two modes of the entire structure participate in the coupling between the outer waveguides. Using a three-mode approximation we found simple conditions for complete power transfer between the outer waveguides: the device length has to match certain multiples of the con- ventionally defined coupling length. The specific form of the relevant modes allows us to design a magneto-optic isolator or circulator with significantly reduced device length (as compared to the conventional nonreciprocal coupler). The performance of the proposed devices is simulated by propagating-mode calculations. Estimates for admissible fabrication tolerances for the layer thicknesses are presented. KW - integrated optics KW - magneto-optic circulator KW - magneto-optic isolator KW - radiatively coupled waveguides KW - three-guide coupler Y1 - 1997 U6 - https://doi.org/10.1117/1.601255 VL - 36 IS - 3 SP - 889 EP - 895 PB - SPIE ER - TY - JOUR A1 - Shamonin (Chamonine), Mikhail A1 - Lohmeyer, Manfred A1 - Hertel, Peter T1 - Directional coupler based on radiatively coupled waveguides JF - Applied optics (Appl. Opt.) N2 - We investigate a system of two waveguides with leaky modes sharing a common substrate (radiatively coupled waveguides). The main advantage of such a system is the possibility of remote coupling. A perturbation theory is developed for both TE and TM polarization. Numerical calculations of dispersion curves and of the coupling length allow us to determine the limitations of the perturbation theory. We study the influence of multimode interference on the process of beating by considering the propagation of a given initial field. Finally, we propose a new design for an effective, integrated optical TE-TM polarization splitter. Y1 - 1997 UR - https://opg.optica.org/ao/abstract.cfm?URI=ao-36-3-635 U6 - https://doi.org/10.1364/ao.36.000635 VL - 36 IS - 3 SP - 635 EP - 641 ER - TY - JOUR A1 - Lohmeyer, Manfred A1 - Shamonin (Chamonine), Mikhail A1 - Bahlmann, N. A1 - Hertel, Peter A1 - Dotsch, H. T1 - Radiatively Coupled Waveguide Concept for an Integrated Magneto-Optic Circulator JF - MRS Online Proceedings Library N2 - Three-guide couplers with multimode central waveguides allow for remote coupling between optical channels. A simple three mode approximation turns out to be sufficient for the description of the main features of the power transfer behavior. The specific form of the relevant modes suggests the design of integrated optical isolators and circulators based on magnetic garnet materials. These novel devices are superior to conventional nonreciprocal couplers with respect to the total length and admissible fabrication tolerances. We characterize the isolation performance and the transmission loss for the proposed devices by propagating mode simulations and estimate the influence of geometry parameter deviations. Y1 - 1998 U6 - https://doi.org/10.1557/PROC-517-519 SN - 1946-4274 IS - 517 SP - 519 EP - 524 ER - TY - JOUR A1 - Lohmeyer, Manfred A1 - Shamonin (Chamonine), Mikhail A1 - Hertel, Peter T1 - Boundary conditions for the finite difference beam propagation method based on plane wave solutions of the Fresnel equation JF - IEEE Journal of Quantum Electronics N2 - Each particular implementation of the beam propagation method (BPM) requires a special procedure allowing for radiation to leave the computational window. We propose a new approach to constructing the finite difference schemes of the BPM at the boundary of the computational window. These schemes are independent of the computed fields and allow for a similar treatment of both interior and boundary points. The new approach can be further improved by correcting the field values at the boundary points according to Hadley's method. The algorithm is easy to implement for both two- and three-dimensional structures. The new method considerably reduces computation times because the propagation matrices remain constant in longitudinally invariant sections, thus avoiding repeated LU-decompositions. The basic idea-establishing the finite difference scheme such that locally exact, approximate, or plausible solutions are recovered-may be of interest for other efforts to solve partial differential equations by the finite difference method. KW - Boundary conditions KW - Finite difference methods KW - Optical propagation KW - Matrix decomposition KW - Computational modeling KW - Refractive index KW - Maxwell equations KW - Sparse matrices KW - Partial differential equations KW - Shape Y1 - 1997 U6 - https://doi.org/10.1109/3.552269 SN - 0018-9197 VL - 33 IS - 2 SP - 279 EP - 286 ER - TY - JOUR A1 - Shamonin (Chamonine), Mikhail A1 - Lohmeyer, Manfred A1 - Hertel, Peter T1 - Analysis of power-dependent switching between radiatively coupled planar waveguides JF - Journal of Lightwave Technology N2 - Effective coupling between two remote optical waveguides without branching sections can be achieved in a three-guide system with multimode central waveguide. We investigate the nonlinear power switching of c.w. laser radiation by such radiatively coupled waveguides. It is shown that effective all-optical switches with spatially well separated input/output channels can be realized although the influence of multimode interference on the switching characteristics becomes more pronounced for increasing thickness of the central guide. Different coupling regimes are specified, and the changes in switching characteristics during the transformation from one regime to another is studied. Numerical calculations for the critical power are compared with an approximate analytical expression. It is also shown that, at a moderate input power, a small number of modes determines the switching behavior. KW - Electromagnetic coupling KW - Planar waveguide KW - Optical waveguides KW - Nonlinear optics KW - Optical coupling KW - Optical surface waves KW - Optical refraction KW - Optical variables control KW - Refractive index KW - Optical switches Y1 - 1997 UR - 1558-2213 U6 - https://doi.org/10.1109/50.588671 VL - 15 IS - 6 SP - 983 EP - 989 PB - IEEE CY - New York ER - TY - JOUR A1 - Kravanja, Gaia A1 - Kriegl, Raphael A1 - Hribar, Luka A1 - Glavan, Gašper A1 - Drevenšek‐Olenik, Irena A1 - Shamonin (Chamonine), Mikhail A1 - Jezeršek, Matija T1 - Magnetically Actuated Surface Microstructures for Efficient Transport and Tunable Separation of Droplets and Solids JF - Advanced Engineering Materials N2 - Efficient transportation of droplets (∽10 ¹ ̶̶̶̶ 10 ² µl) and small solid objects (∽10 ¹ ̶ 10 ² mm ³ ) have important applications in many fields, such as microfluidics, lab‐on‐a‐chip devices, drug delivery, etc. A novel multifunctional surface consisting of a periodic array of micro‐lamellae from a soft magnetoactive elastomer (MAE) on a plastic substrate is reported for these purposes. The physical origin of the propulsion is the bending of soft magnetic lamellae in non‐uniform magnetic fields, which is also observed in uniform magnetic fields. The magnetoactive surface is fabricated using a facile and rapid method of laser ablation. The propulsion of items is realized using a four‐pole rotating magnet. This results in a cyclic lamellar fringe motion over the micro‐structured surface and brings an advantage of easy reciprocation of transport by rotation reversal. Two modes of object transportation are identified: “pushing” mode for precise control of droplet and solid positioning and “bouncing” mode for heavier solid objects transportation. A water droplet of 5 μl or a glass sphere with a 2.1 mm diameter can be moved at a maximum speed of 60 mm s ⁻¹ . The multifunctionality of the proposed mechatronic platform is demonstrated on the examples of selective solid‐liquid separation and droplet merging. KW - Keywordslaser micromachinings KW - magnetoactive elastomers KW - magnetoresponsivesurfaces KW - object separations KW - object transportations Y1 - 2023 U6 - https://doi.org/10.1002/adem.202301000 SN - 1527-2648 VL - 25 IS - 22 SP - 1 EP - 11 PB - Wiley-VCH ER - TY - JOUR A1 - Kriegl, Raphael A1 - Kovalev, Alexander A1 - Shamonin (Chamonine), Mikhail A1 - Gorb, Stanislav T1 - Tunable contact angle hysteresis on compliant magnetoactive elastomers JF - Extreme Mechanics Letters N2 - It is shown that the advancing (ACA) and receding (RCA) contact angles of water on extremely soft (shear modulus of the order of 10 kPa) magnetoactive elastomer (MAE) films significantly depend on the applied magnetic field. The difference between these angles, known as the contact angle hysteresis, is examined. The roles of the filler concentration and material softness are elaborated. The highest change in the contact angle hysteresis (CAH) from 34° in the absence of magnetic field to 76° in a magnetic field of 0.4 T is achieved for the softest sample with the lowest mass fraction of iron particles (70 wt%). The dependence of the CAH on magnetization history (“magnetic hysteresis”) is observed. This magnetic hysteresis is clearly pronounced for the ACA and has little effect on the RCA. Magnetic field-induced changes of the surface roughness exhibit qualitatively the same hysteresis behavior with regard to the external magnetic field as the ACA. The results are promising for the development of smart surfaces for applications where the dynamic wetting has to be controlled. KW - Magnetoactive elastomers KW - Dynamic wetting KW - Magnetic hysteresis KW - Contact angle hysteresis Y1 - 2023 U6 - https://doi.org/10.1016/j.eml.2023.102049 SN - 2352-4316 VL - 63 PB - Elsevier ER - TY - JOUR A1 - Jezeršek, Matija A1 - Kriegl, Raphael A1 - Kravanja, Gaia A1 - Hribar, Luka A1 - Drevenšek‐Olenik, Irena A1 - Unold, Heiko A1 - Shamonin (Chamonine), Mikhail T1 - Control of Droplet Impact through Magnetic Actuation of Surface Microstructures JF - Advanced Materials Interfaces N2 - An effective method for on-demand control over the impact dynamics of droplets on a magnetoresponsive surface is reported. The surface is comprised of micrometer-sized lamellas from a magnetoactive elastomer on a copper substrate. The surface itself is fabricated using laser micromachining. The orientation of the lamellae is switched from edge-on (orthogonal to the surface) to face-on (parallel to the surface) by changing the direction of a moderate (<250 mT) magnetic field. This simple actuation technique can significantly change the critical velocities of droplet rebound, deposition, and splashing. Rebound and deposition regimes can be switched up to Weber number We < 13 ± 3, while deposition and splashing can be switched in the range of 32 < We < 52. Because a permanent magnet is used, no permanent power supply is required for maintaining the particular regime of droplet impact. The presented technology is highly flexible and enables selective fabrication and actuation of microstructures on complex devices. It has great potential for applications in soft robotics, microfluidics, and advanced thermal management. Y1 - 2023 U6 - https://doi.org/10.1002/admi.202202471 VL - 10 IS - 11 PB - Wiley ER - TY - JOUR A1 - Glavan, Gašper A1 - Belyaeva, Inna A. A1 - Drevenšek‐Olenik, Irena A1 - Shamonin (Chamonine), Mikhail T1 - Experimental study of longitudinal, transverse and volume strains of magnetoactive elastomeric cylinders in uniform magnetic fields JF - Journal of Magnetism and Magnetic Materials N2 - Magnetoactive elastomers (MAEs) are promising materials for realization of magnetic field-controlled soft actuators. Herein, a systematic investigation of magnetic field-induced macroscopic deformations of soft MAE cylinders with a diameter of 15 mm in uniform quasi-static magnetic fields directed parallel to the cylinder’s axis is reported. The measurements were based on image processing. Thirty-six MAE samples differing in the weight fraction of the iron filler (70 wt%, 75 wt% and 80 wt%), alignment of filling particles, and the aspect ratio (0.2, 0.4, 0.6, 0.8, 1.0 and 1.2) were fabricated. MAE cylinders exhibited high relative change in height (up to 35% in the field of 485 kA/m) and lateral contraction. The dependence of the maximum extensional strain on the aspect ratio was obtained and compared with theoretical considerations. A concave dent was formed on the free circular base in magnetic fields. This concavity was characterized experimentally. A significant volumetric strain of the order of magnitude of 10% was calculated in MAEs for the first time. In consequently repeated magnetization cycles, the remanent extensional strain significantly increased after each cycle. The results are qualitatively discussed in the framework of the modern views on the magnetically induced macroscopic deformations of MAEs. The directions of further research are outlined. Y1 - 2023 U6 - https://doi.org/10.1016/j.jmmm.2023.170826 SN - 0304-8853 VL - 579 PB - Elsevier ER -