Article
Acoustics
Zewen Gu, Xiaonan Hou, Jianqiao Ye
Summary: An advanced analytical spring model is proposed in this study to address the non-linear effects of variable coil diameter, spring pitch and coil contact that exist in helical springs of arbitrary shapes. It aims to expand the available spring design and analysis domain to a wider non-linear space. The proposed model has excellent accuracy in estimating mechanical properties of non-linear springs in both static and dynamic conditions by comparing with experimental and FE results.
JOURNAL OF SOUND AND VIBRATION
(2021)
Article
Mechanics
Espen Jettestuen, Olav Aursjo, Jan Ludvig Vinningland, Aksel Hiorth
Summary: We propose a general method to reduce compressibility effects in pressure driven lattice Boltzmann simulations involving complex geometries by introducing a preconditioning step for the flow system. The method involves determining the geometry dependent contribution to a pressure field induced by a given set of pressure boundary conditions using Laplace's equations. This method can be applied to both stationary and non-stationary flow situations without recalculating the preconditioning step.
Article
Mechanics
Maoqiang Jiang, Zhaohui Liu
Summary: A simple and efficient boundary treatment is proposed for periodic boundary conditions in a lattice Boltzmann method for simulating particle-laden flows in complex geometries, addressing some issues that were encountered previously.
Article
Multidisciplinary Sciences
Sumito Tsunegi, Tomohiro Taniguchi, Daiki Suzuki, Kay Yakushiji, Akio Fukushima, Shinji Yuasa, Hitoshi Kubota
Summary: Neuromorphic computing using spintronic devices, such as spin-torque oscillators, has been studied for energy-efficient data processing. Stochasticity in magnetization dynamics poses challenges for computation accuracy, but plays a key role in stochastic computing and machine learning. Methods to suppress or enhance stochastic response in spintronic devices have been developed, including utilizing the spin-transfer effect and applying a magnetic field.
SCIENTIFIC REPORTS
(2021)
Review
Biophysics
David C. Alsop, Ece Ercan, Olivier M. Girard, Alex L. Mackay, Carl A. Michal, Gopal Varma, Elena Vinogradov, Guillaume Duhamel
Summary: Off-resonance radio frequency irradiation can induce the ordering of proton spins in the dipolar fields of their neighbors, in molecules with restricted mobility. This dipolar order decays with a characteristic relaxation time, T-1D, that is very different from the T-1 and T-2 relaxation of the nuclear alignment with the main magnetic field. Inhomogeneous magnetization transfer (ihMT) imaging is a refinement of magnetization transfer (MT) imaging that isolates the MT signal dependence on dipolar order relaxation times within motion-constrained molecules.
NMR IN BIOMEDICINE
(2023)
Article
Engineering, Mechanical
Tongtong Yan, Dong Wang, Tangbin Xia, Jie Liu, Zhike Peng, Lifeng Xi
Summary: This article investigates how the LDA algorithm can locate informative frequency bands for machine health monitoring, and proposes a new health indicator to detect fault initiation and track degradation trajectory during a machine life cycle. The effectiveness of the proposed method is validated through simulation and experimental studies. The interpretability of this approach provides a new perspective for developing physics-informed machine learning technology by combining data-driven models with physics-based knowledge.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Multidisciplinary Sciences
Kaihang Guo, Liang Zou, Lingjun Dai, Li Zhang
Summary: This study establishes a three-dimensional model of nanocrystalline alloy based on the stochastic anisotropy theory and symmetry principle. The movement of magnetic moments under high-frequency sinusoidal excitation is investigated by defining the magnetic moment deflection velocity and magnetization rate. The results show that the magnetic moment deflection velocity is positively correlated with the frequency and amplitude of the alternating magnetic field, with the frequency having a more significant effect. Additionally, the magnetization rate is also positively correlated with the alternating magnetic field, with the frequency having a larger impact.
Article
Materials Science, Multidisciplinary
E. Schmoranzerova, T. Ostatnicky, J. Kimak, D. Kriegner, H. Reichlova, R. Schlitz, A. Badura, Z. Soban, M. Muenzenberg, G. Jakob, E-J Guo, M. Klaeui, P. Nemec
Summary: We observed a giant quadratic magneto-optical effect in a 50 nm thick YIG layer. Through theoretical and experimental methods, we quantified both linear and quadratic magneto-optical effects in the studied material. The quadratic magneto-optical signal in the thin YIG film exceeded the linear response, reaching values of 450 grads that are comparable with Heusler alloys or ferromagnetic semiconductors. This enhancement is attributed to antiferromagnetic coupling of two Fe sublattices. We also found that the choice of experimental conditions, particularly the wavelength, is crucial for optimizing the quadratic magneto-optical effect.
Article
Physics, Applied
Suko Bagus Trisnanto, Tamon Kasajima, Taiju Akushichi, Yasushi Takemura
Summary: This study achieved a harmonic-rich signal by utilizing linear magnetization responses of magnetic nanoparticles, providing a new approach for magnetic particle imaging. By using a magnetoresistive sensor, the research team proposed a strategy to exploit the linear responses of tracers, resulting in high-contrast images of a solid ferucarbotran phantom and bringing new expectations for clinical use of MPI.
APPLIED PHYSICS EXPRESS
(2021)
Article
Engineering, Mechanical
Chaoqing Min, Martin Dahlmann, Thomas Sattel
Summary: The study introduces a novel semi-active vibration control concept that converts vibration energy to potential energy stored in springs. By decomposing the control force into two components and using an equivalent linear system, the study accurately addresses the vibration control issue in steady state response and demonstrates the occurrence of energy conversion limit in the vibration control system.
NONLINEAR DYNAMICS
(2021)
Article
Engineering, Mechanical
Robin de Rozario, Tom Oomen
Summary: This paper develops an FRF modeling framework for LPV systems, allowing the identification of LPV FRF models from global experiments. The method generalizes ETFE to periodically scheduled LPV systems and is successfully used to estimate a SISO LPV FRF for an experimental motion system.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2021)
Article
Engineering, Civil
Ssu-Chieh Chen, Chi-Chin Tsai, Duhee Park
Summary: Frequency-dependent equivalent linear (FD-EQL) site response analysis methods, developed as potential substitutes for the EQL procedure to better simulate the nonlinear soil response, have been reported to overpredict the high-frequency wave propagation. Modified procedures proposed to overcome this limitation have demonstrated to improve the fits with the nonlinear analysis results. The method has not yet been applied to perform a deconvolution analysis, where a conventional EQL analysis often fails to converge or provide reliable estimate.
JOURNAL OF EARTHQUAKE ENGINEERING
(2023)
Article
Mathematics, Applied
Meng Du, Jie Wei, Meng-Yu Li, Zhong-ke Gao, Juergen Kurths
Summary: In this paper, a novel interconnected ordinal pattern network is proposed to investigate the spatial coupling behaviors of gas-liquid two-phase flow patterns using multivariate fluctuation signals as observations. Two network indices, global subnetwork mutual information (I) and global subnetwork clustering coefficient (C), are used to quantify the spatial coupling strength of different flow patterns. The evolutionary behaviors of gas-liquid two-phase flow patterns are further characterized by calculating the proposed coupling indices under different flow conditions. The proposed interconnected ordinal pattern network provides a new tool for understanding the evolutional mechanisms of multi-phase flow systems and can be applied to investigate coupling behaviors in other complex systems with multiple observations.
Article
Mathematics
Leopoldo Prieto, Alejandro Quesada, Ana Maria Gomez Amador, Vicente Diaz
Summary: A mathematical equation system was developed to calculate the natural frequencies of helical springs, and its predictions were compared with finite element simulation. The general equations governing the vibration of helical springs were derived, describing the characteristics of the spring oscillation.
Article
Chemistry, Multidisciplinary
Emilio Martines, Roberto Cavazzana, Luigi Cordaro, Matteo Zuin
Summary: The paper discusses the design and principles of the helical resonator, as well as the generation of high voltage at radio frequencies and its characteristics. By studying factors such as resonance conditions, tap point position, and capacitive load, it analyzes how to maximize the performance of the resonator and match it to the power supply.
APPLIED SCIENCES-BASEL
(2021)
