For over twenty years, the scientific committee of EFOMP has played an important role supporting the European medical physics community. In its management of special interest groups in Radionuclide Internal Dosimetry, Dental Imaging, Particle Therapy and Magnetic Resonance Imaging, the committee has helped drive and direct science, professional matters and education in these fields. The committee also helps form and manage working groups who work within the European community and beyond to create specific outputs which help medical physicists in the field - outputs such as curricula and best practice guidelines. Wherever possible, to harmonise approaches worldwide, much of this work is done in collaboration with international partners such as AAPM, ESTRO, EANM, ESR and the IAEA. Moving forward, the scientific committee will continue to support medical physicists in their work on innovation and new technologies, improvements to patient safety and helping make patient focussed medical physics practice the best that it can be.

Mode Weighting Method for modeling and internal resonance of spatial folded beams

Nonlinear acoustic propagation plays a crucial role in many practical applications, such as medical therapy and underwater communications. However, the nonlinear propagation behavior of multi-frequency acoustic waves radiated from nonlinear vibrating structures remains insufficiently understood. This study develops a coupled structural-acoustic model to numerically investigate the nonlinear acoustic radiation and propagation from a hyperelastic structure undergoing nonlinear vibration. Both geometric and material nonlinearities are incorporated into the finite element model of the structure, while nonlinear acoustic propagation in the surrounding fluid is solved using a high-order finite-difference time-domain scheme. The fluid-structure coupling is achieved through an improved immersed boundary method, which ensures the implicit satisfaction of compatibility conditions at the interface. Based on this framework, the nonlinear transient acoustic responses of the hyperelastic structure are examined, and the effects of the fluid nonlinearity parameter B/A and excitation amplitude on multi-frequency wave interactions are systematically analyzed. The numerical results demonstrate that the multi-frequency response induced by structural nonlinearity provides the necessary foundation for nonlinear wave-wave interactions, which, in turn, redistribute energy in different frequency components and modify the spatial patterns of high-order acoustic harmonics.

Objective: To evaluate the feasibility of deep learning-based automated segmentation of the facial and vestibulocochlear nerves within the cisternal and intracanalicular segments on high-resolution magnetic resonance imaging.Study design and setting: This was a retrospective imaging study conducted at a tertiary referral center.Patients: Twenty-two adult patients with normal internal auditory canal magnetic resonance imaging and no skull base pathology were included.Methods: Manual segmentation of the facial and vestibulocochlear nerves was performed on axial constructive interference in steady state magnetic resonance images using 3D Slicer. The dataset was divided into training, validation, and test subsets. A three-dimensional U-Net convolutional neural network was trained with standard augmentation. Additional Medical Open Network for Artificial Intelligence-based architectures, including Attention U-Net, Dynamic U-Net, and U-Net++, were trained and compared under identical preprocessing and training conditions.Results: All models generated anatomically plausible segmentations on qualitative review. The baseline U-Net achieved a test Dice similarity coefficient of 0.6398. Dynamic U-Net demonstrated the highest validation performance (Dice = 0.6236), while U-Net++ achieved the highest test performance (Dice = 0.6716). Attention U-Net demonstrated lower performance in this small-structure segmentation task. Performance trends were consistent with the challenges inherent to segmenting thin neural structures with limited voxel representation.Conclusions: Deep learning-based segmentation of the facial and vestibulocochlear nerves on high-resolution magnetic resonance imaging is feasible within a limited retrospective dataset. Model selection appears important for small-structure segmentation, with Dynamic U-Net and U-Net++ demonstrating relatively higher performance trends within this limited dataset. Although performance metrics were modest and derived from a limited test dataset, automated segmentation showed consistent anatomic overlap with manual labels on qualitative review. These findings provide preliminary technical groundwork for future validation in larger cohorts and extension to clinically relevant applications such as cochlear nerve integrity in implant candidates.

Parameter optimization and performance evaluation of a nonlinear energy sink for vibration reduction in TLP floating wind turbine

Rotor–stator nonlinear interactions are commonly observed in rotating machines due to the need for reduced rotor–stator clearance, which is essential for achieving high efficiency. Additionally, the effects of acceleration resulting from aircraft maneuvering are not considered in the current rotor–stator interaction model. This study establishes a rotor–stator rubbing model that incorporates additional acceleration. An event function is utilized to detect contact and noncontact states. Responses ranging from low to high rotating speeds are analyzed through bifurcation diagrams and full-spectrum methods to illustrate the complex dynamic characteristics. Orbits, fast Fourier transform spectra, and Lyapunov exponents are plotted to demonstrate the nonlinear behaviors at specific speeds and accelerations. The results indicate that regions of chaotic motion expand, while areas of internal resonance decrease at low nondimensional gravity coefficients. Conversely, at high nondimensional gravity coefficients, the chaotic regions diminish, and multiple periodic motions emerge.

Topological phases in one-dimensional lattices are usually described by fixed, frequency-independent Hamiltonians, where topology is determined solely by structural parameters. However, in many wave-based systems with internal resonances, effective couplings become intrinsically dispersive and depend on the eigenfrequency itself. Here, we develop an analytical theory of such using a trimer (SSH3) mass-spring lattice as a minimal model. By exactly eliminating the internal sublattice, the three-band SSH3 dynamics are mapped onto an effective two-sublattice Hamiltonian with frequency-dependent inertial and coupling terms. Because the effective parameters depend explicitly on the eigenfrequency, the resulting eigenvalue problem is nonlinear in ω and self-consistently reproduces the full three-band spectrum despite the two-level representation. This mapping reveals that the resonant effective coupling G 2 ( ω ) acts as a bifurcation parameter controlling band inversion, redistribution of integer winding numbers, and the emergence of edge-localized modes. We show that a sign reversal of G 2 ( ω ) induces a frequency-selective topological transition accompanied by a winding redistribution ( ν 1 , ν 2 , ν 3 ) = ( − 1 , 2 , − 1 ) and analytically predictable in-gap edge states governed by closed-form localization criteria. Within this framework, the bulk-edge correspondence is not determined by a fixed Hamiltonian but by the effective Hamiltonian evaluated self-consistently along the bulk dispersion relation. The formulation is further extended to adiabatically modulated lattices, where locally nontrivial Berry curvature and alternating topological charges emerge on the ( q , t ) torus, while the global Chern number remains neutral. Because dispersive renormalization arising from internal degrees of freedom is ubiquitous in phononic, photonic, and other wave-based lattice systems, the present theory establishes a general analytical framework for topological phases in dispersive multisublattice media beyond conventional static tight-binding descriptions.

This study investigates the nonlinear dynamic stability and internal resonance of osteon micro-beams under localized thermal gradients. Utilizing Nonlocal Strain Gradient Theory (NSGT), the size-dependent behavior of the Haversian system is modeled to bridge microscopic nuances and macroscopic thermal-mechanical responses. The governing equations are derived and solved via the Method of Multiple Scales (MMS) to determine nonlinear frequency-response characteristics. The results indicate that thermal gradients cause frequency reduction and convergence, while the nonlinear response retains a persistent hardening-type behavior at large amplitudes. A critical highlight is the identification of a 1:3 internal resonance threshold. At specific parametric configurations, the system exhibits sophisticated modal coupling, a ‘double-peak’ resonance profile, and the saturation phenomenon, indicating nonlinear energy transfer between the fundamental and second modes. Furthermore, 3D coupled parametric maps illustrate a ‘stability canyon’, highlighting osteon dynamic sensitivity under combined thermal and nonlocal influences. The obtained nonlinear vibration characteristics and internal resonance behavior may provide useful insight into how dynamic loading conditions influence stress redistribution and mechanical response at the osteon scale.

ABSTRACT During the 1960s and 1970s, anticolonial liberation narratives transcended the geopolitical boundaries of the Global South and profoundly shaped nationalist movements in Europe. Although the anticolonial frame gained momentum during this period, its overtly confrontational rhetoric was gradually supplanted by moderate frames that aligned with popular demands. Through 20 in‐depth interviews with key Galician nationalists, we explore the tension between the movement's public‐facing frames and its hidden interpretative frames that are rooted in anticolonial thought. The findings reveal that, although explicit references to colonialism have largely disappeared from official discourse, the movement's internal cohesion relies on an unspoken grammar of resistance. The conclusions highlight the need to complement the study of a movement's externally resonant public discourse with an investigation of its internally inherited interpretative frames. Only through this combined approach can scholars identify the hidden frames whose internal resonance sustains both long‐term group cohesion and strategic alignment.

Study on broadband vibration energy harvesting mechanism via 1:2 internal resonance in a disc-shaped frequency upconverting resonator

Dual-stage wind energy harvester utilizing synergy between two wake-galloping mechanisms and their internal resonance phenomena

Vibration analysis and control method of internal resonant nonlinear system based on coupled nonlinear mode approach

Abstract The ability to control the dynamic response of structured materials through externally induced stress fields has received growing attention in the design of adaptive systems. This study investigates a novel approach to modulating wave propagation characteristics by exploiting stress fields generated by piezoelectric materials. A refined electromechanical model is developed within the Carrera Unified Formulation (CUF), enabling a fully coupled analysis of prestressed structures through the introduction of geometric stiffness effects. The model is then applied to two different configurations: a metamaterial with embedded piezoelectric inclusions and a metamaterial based on internal resonators. The results demonstrate that, while embedded piezoelectric elements can induce tunable bandgap shifts, the required excitation fields exceed the operational limits of conventional piezoelectric materials, suggesting the need for alternative architectures. Conversely, the resonator-based approach successfully generates tunable bandgaps within frequency ranges of interest, particularly in the acoustic domain, demonstrating its potential for adaptive wave control application. Additionally, the study explores the effect of complex stress distributions, demonstrating the flexibility of the proposed methodology in handling alternating compression and tension regions to increase the tunability of the material.

Background Visible tympanic membrane (TM) pulsation is an uncommon otoendoscopic finding that may reflect middle ear or intracranial pathology. Objective To characterize clinical features and etiologies of TM pulsation in an outpatient otology setting. Methods We retrospectively reviewed 34 consecutive adults (mean age 56 ± 13 years) with TM pulsation identified on routine otoendoscopy (January 2022–September 2024). All patients underwent audiologic testing and temporal bone computed tomography; internal auditory canal magnetic resonance imaging was performed when indicated. Patients with neurological symptoms or suspected intracranial hypertension were excluded. Results Middle ear effusion was the most common cause (61.8%), frequently associated with pulsatile tinnitus. Healed TM perforation accounted for 26.5% of cases. Less common etiologies included jugular diverticulum, arachnoid granulation with tegmen dehiscence, temporal encephalocele, and postoperative TM graft pulsation. Imaging findings supported correlations between TM movement and underlying middle ear or adjacent structural abnormalities. Conclusion In outpatient populations, visible TM pulsation predominantly reflects middle ear cavity conditions rather than intracranial pressure changes. Awareness of this sign may facilitate early detection of clinically relevant lesions, including encephalocele and vascular anomalies, and guide timely imaging and management.

In recent years, microelectromechanical systems (MEMS) filters exploiting structural nonlinearity and coupled resonance have enabled programmable passband shaping beyond traditional single-peak designs, yet they still face low operating frequencies and limited electrical tuning range. Here, leveraging 1:1 internal resonance, we propose a gate-programmable tuning strategy for two-dimensional (2D) material-based nanoelectromechanical systems (NEMS), enabling high-frequency operation and wide-range reconfigurability. Benefiting from the high resonant frequency and wide electrostatic tunability of 2D materials such as MoS2, our theoretical analysis indicates wide-range programmability up to f/f0≈200%. Sweeping Vg1=Vg2 from 9 to 16 V while maintaining ≈1:1 frequency matching shifts the passband upward quasi-linearly at 4.4~MHz/V. In contrast, with the coupling strength nearly unchanged, mV-level bias mismatch perturbs the frequency ratio by 10-5, enabling highly sensitive bandwidth trimming from 3.18 to 5.20 kHz, supporting a two-step strategy of coarse center-frequency tuning followed by fine bandwidth control. To broaden the bandwidth, we further analyze a three-drum case: with Vg1=Vg2=Vg3=16 V, the bandwidth reaches 21.79 kHz with a 5056.05 dB/MHz transition slope and 0.95 dB ripple, which is nearly 4 times wider than the two drum case with the same gate voltage. This study shows that 1:1 internal resonance can be used to tune the bandpass response of NEMS resonators. All results are obtained from theoretical modeling and numerical simulations.

After entering the ear, sound waves propagate as surface waves along the cochlea’s basilar membrane. In recent work, we showed numerically that the system supports two types of modes: localized resonant modes, which underpin the modern understanding of cochlear mechanics, and a novel class of spatially extended modes. Here, we develop an analytic framework that explains the emergence of this mode structure. We show that extended modes arise from globally continuous standing-wave solutions, whereas localized modes result from internal resonance requiring matching across a singular point. These results clarify the generic structure of cochlear wave equations.

Extensive research has solved the dynamic problems of electromagnetic bearings under 1:1 internal resonance, but the complex nonlinear behavior of a 12-pole variable stiffness system under 1:2 internal resonance has not been explored to a large extent. This paper aims to bridge this gap by providing comprehensive dynamic analysis and PD control strategies for such systems. First, the expression for the electromagnetic force in the system is derived based on electromagnetic theory, applying Newton’s second law and considering the effect of rotor gravity. The resulting differential equations governing the dynamics and control of the magnetic bearing, which include quadratic and cubic terms, are then derived. Next, the relationships between the first-order and second-order natural frequencies are analyzed, taking into account 1:2 internal resonance, primary parameter resonance, and 1/2 subharmonic resonance. A perturbation analysis of the system is performed using the method of multiple time scales, yielding the four-dimensional averaged equations in both polar and Cartesian coordinates, as well as the amplitude–frequency response equations. Finally, numerical simulations reveal distinct vibration modulation patterns: parametric excitation dominates the first-order modal response, whereas external forcing preferentially excites the second-order mode, resulting in anisotropic oscillations along orthogonal axes. Moreover, the differential gain is demonstrated to be a critical factor in the suppression of chaos and bifurcations. These results significantly advance the understanding of the nonlinear dynamic behaviors inherent in active electromagnetic bearing systems.

This study investigates a non-ideal magnetic levitation system (NIMLS) for energy harvesting, with particular emphasis on the influence of the oscillating core mass. The system is excited by an electrodynamic shaker, leading to strongly nonlinear oscillatory behavior governed by a coupled equation resembling the Duffing oscillator. Perturbation techniques are employed to analyze the system dynamics under the combined action of a negative velocity and negative acceleration controller (NVC+NAC), focusing on primary resonance and 1:1 internal resonance condition. Analytical solutions are derived to describe the system response, while MATLAB-based numerical simulations are used to validate the theoretical results. The stability of the system under primary resonance is examined using the Routh–Hurwitz criterion. Furthermore, the effects of structural constraints and system parameters on the dynamic performance of the primary system equipped with the NVC+NAC controller are investigated. A comparative analysis between analytical and numerical solutions confirms the accuracy of the perturbation-based approximations and demonstrates the effectiveness of the proposed controller in suppressing vibration amplitudes.

Broadband wave energy harvesting via internal resonance: Experimental insights

Internal resonance in rotating conductive circular plate subjected to parametric excitation within coupled air–magnetic fields