Local Vibration Research Articles

A theory of phonon-induced friction on molecular adsorbates

In this manuscript, we provide a general theory for how surface phonons couple to molecular adsorbates. Our theory maps the extended dynamics of a surface's atomic vibrational motions to a generalized Langevin equation, and by doing so captures these dynamics in a single quantity: the non-Markovian friction. The different frequency components of this friction are the phonon modes of the surface slab weighted by their coupling to the adsorbate degrees of freedom. Using this formalism, we demonstrate that physisorbed species couple primarily to acoustic phonons while chemisorbed species couple to dispersionless local vibrations. We subsequently derive equations for phonon-adjusted reaction rates using transition state theory and demonstrate that these corrections improve agreement with experimental results for CO desorption rates from Pt(111).

Exploring superionic conduction in lithium oxyhalide solid electrolytes considering composition and structural factors

Lithium (Li) oxyhalides have emerged as promising solid electrolyte candidates for all-solid-state batteries (ASSBs) due to their superior ionic conductivity and excellent cathode capability. However, the mechanism of Li transport in oxyhalides has remained unclear due to the complex nature of these compounds, which often comprise multiple phases such as crystalline and amorphous structures. Herein, a first-principles study using density functional theory and ab initio molecular dynamic simulation is performed to gain a theoretical insight into the structural behavior and conduction pathway in oxyhalide electrolytes. Li2.5ZrCl5.5O0.5 electrolyte, as a case of study, is comprehensively investigated by considering various phases. It’s revealed that the P3̅m1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\rm{P}}\\bar{3}{\\rm{m}}1$$\\end{document} phase is energetically more stable and exhibits one order of magnitude higher Li conductivity compared to the C2/m phase among potential crystalline phases (1.63 mS cm−1 versus 0.24 mS cm−1 at room temperature). Interestingly, an amorphous phase with even higher ionic conductivity (~40 mS cm−1) can be generated by creating LiCl-deficient Li-Zr-O-Cl compounds. The remarkably high ionic conductivity suggests that the amorphous structure is likely the dominant conducting pathway, facilitating fast Li transport due the weak bonding between Li and other atoms. Cl anion mobility is also observed in the amorphous phase through mean square displacement (MSD) calculation, although further analyses revealed this to be localized vibration. This study sheds light on the nature of oxychloride structures and promotes a deeper understanding of the superionic conduction mechanism in oxychlorides, which will contribute to the development of advanced solid electrolytes and ASSBs.

Assessing the Impact of Novafon Local Vibration Voice Therapy on Voice Disorders: A Comprehensive Review

Assessing the Impact of Novafon Local Vibration Voice Therapy on Voice Disorders: A Comprehensive Review

The research of vibration localization under strong disturbances using modal analysis methods

Abstract Vibration localization is a typical feature of aperiodic structures. This work investigates the vibration localization of framed cylindrical shells with a high disturbance degree. First, the spring oscillator system is considered an example to reveal the general law governing how high disturbance degree influences the vibration transmission in a structure. Then the strong localization coefficient is calculated using the modal analysis method. Finally, the conclusions of the one-dimensional systems are applied to the two-dimensional structures based on the passband approximation equivalent method to derive the strong localization coefficient of the aperiodic ring-ribbed cylindrical shell. This study realizes quantitative calculation of the vibration localization coefficient under high disturbance degree. The results of this work provide theoretical support for reducing the vibration transmission performance of a structure by increasing the degree of disturbance.

Preface

Abstract This collection includes accepted papers from the 2024 3rd Workshop on Material Science, Modelling, Engineering, and Applications in Vibration Engineering (MVE 2024). With a special focus on material science, MVE 2024 welcome research papers on the relationship between structure, properties, and uses of materials (including metals, ceramics, glasses, polymers, energy materials, electrical materials, composite materials, fibers, nanostructured materials, nanocomposites, and biological and biomedical materials). In MVE 2024, we have received 29 submissions and 17 are accepted after peer review carried out in Morressier online submission system, with 48 reviewers participated. The final acceptance rate is 58%. For cost efficiency and eco-protection considers, the webinar of MVE 2024 (Almaty, Kazakhstan) provides free access to all attendees and audiences through TencentMeeting. The webinar consists three parts, keynote speech by Prof. Muhammad Suyfan Javed, oral speeches and posters. The keynote speech lasts for 30 minutes and each oral speech is assigned with 15 minutes of presentation and 5 minutes for Q&A. The posters are presented on the webinar and the website for further post-webinar communications. Though poster presenters are not able to get instant communication with audience, they are given opportunities to get connected via emails. Among the seventeen papers in the proceedings, five papers, including Hydration characteristics and kinetic analysis of polyacrylamide (PAM) anti-dispersion cement-based materials, Dynamic analysis of a hydraulic motor lifting auxiliary beam of monorail crane, Research of localization of vibration under strong disturbances using modal analysis methods, Research on seismic response and enhanced resistance support of cross fault tunnel models in healthcare, Experimental study on the influence of different sampling methods on the stress-strain and strength characteristics of weathered and water rich sandstone, are presented with oral speeches. The rest papers are all presented with posters. The proceedings editors hope that this collection can provide guidance for problem solving and further studies. List of General Chair and Technical Program Committee are available in this Pdf.

In-Plane Overdamping and Out-Plane Localized Vibration Contribute to Ultralow Lattice Thermal Conductivity of Zintl Phase KCdSb.

Zintl phases typically exhibit low lattice thermal conductivity, which are extensively investigated as promising thermoelectric candidates. While the significance of Zintl anionic frameworks in electronic transport properties is widely recognized, their roles in thermal transport properties have often been overlooked. This study delves into KCdSb as a representative case, where the [CdSb4/4]- tetrahedrons not only impact charge transfer but also phonon transport. The phonon velocity and mean free path, are heavily influenced by the bonding distance and strength of the Zintl anions Cd and Sb, considering the three acoustic branches arising from their vibrations. Furthermore, the weakly bound Zintl cation K exhibits localized vibration behaviors, resulting in strong coupling between the high-lying acoustic branch and the low-lying optical branch, further impeding phonon diffusion. The calculations reveal that grain boundaries also contribute to the low lattice thermal conductivity of KCdSb through medium-frequency phonon scattering. These combined factors create a glass-like thermal transport behavior, which is advantageous for improving the thermoelectric merit of zT. Notably, a maximum zT of 0.6 is achieved for K0.84Na0.16CdSb at 712 K. The study offers both intrinsic and extrinsic strategies for developing high-efficiency thermoelectric Zintl materials with extremely low lattice thermal conductivity.

Theoretical and simulation study on the vibration modes of shear walls in prefabricated modular construction

Abstract As prefabricated construction advances, the enhanced informatization and the industrialized modular construction method of MIC (Modular integrated construction) shear walls have been widely applied in real projects. MIC shear walls are generally made up of prefabricated wall modules with varying strength grades, using concrete of various ages, and are combined with cast-in-place concrete. Due to the unique construction requirements of these walls, defects such as interfacial delamination and internal voids might occur, arising from factors like concrete shrinkage and creep, complex interfacial structures, inadequate compaction during vibration, and construction process issues. Since these interfacial defects cannot be visually inspected from the exterior, developing non-destructive testing (NDT) methods specifically for detecting such defects in shear walls becomes an urgent necessity. This paper utilizes a combination of theoretical analysis and numerical simulation to explore the vibration modes of MIC shear walls with hidden defects. First, a theoretical model is proposed for the local vibration modes of MIC shear wall shells with consideration of interfacial delamination defects. Then, a numerical simulation model is established based on MIC shear wall construction and defect features to simulate the vibration behavior accurately. Finally, after examining the theoretical and simulated vibration characteristics of MIC shear walls, a significant theoretical foundation is established for identifying interfacial defects in MIC shear walls.

Asymmetric Polarization in a Rough Multilayer: Towards the Discrimination of Enantiomer Pairs.

Chirality plays a significant part in many vital processes, and to further our level of understanding, there is a steadily growing interest in enhancing the yield of enantioselective processes. Here, a multilayer with etched grooves is activated in a Kretschmann geometry and consists of alternating platinum Pt, silica SiO2, and silicon Si, as well as a silver Ag layer. Due to the production process, the groove surface exhibits a micrometric roughness, characterized by a typical vibrational mode at ω = 96 MHz. The mode is attributed to a localized acoustic vibration and has been detected as a transmitted signal. The outcomes of the inquiry include plasmonic amplification of the transmitted signal and its wavevector-less nature; in addition, it is shown that the signal is depolarized in reference to the incident beam because of the rough surface. When the Kretschmann scheme is combined with the depolarization brought on by the roughness, a built-in asymmetry results in a higher optical flux of spectrum photons in the depolarized plane than the co-polarized plane, resulting in distinct, enantioselective, and solely polarization-dependent spectral contrast. In conclusion, enantioselectivity is demonstrated for the D,L-penicillamine.

On the role of curvature in the response of air-backed composites to hydrodynamic loading: An experimental study

Composite materials are increasingly utilized in high-performance naval structures, due to their superior properties over traditional materials like steel and aluminum. However, their widespread use is hindered by our limited understanding of their behavior when exposed to marine environments. One of the main loading conditions encountered during operations at sea is the hydrodynamic loading on the side in contact with water. Despite the practical significance of curved composite structures, the state-of-the-art on air-backed composites relies on the study of flat plates. Here, we use three-dimensional digital image correlation and planar particle image velocimetry to study the influence of curvature on the dynamic response of composite plates to hydrodynamic loading. Our findings reveal that curvature significantly influences both structural deformations and flow physics. The curved plate experiences localized vibrations with lower amplitude and higher frequency, caused by its increased stiffness. Additionally, the hydrodynamic pressure at the center of the plate decays faster in time for the curved configuration, highlighting the importance of curvature in shaping fluid–structure interactions. Our results advance the understanding of fluid–structure interactions in composite materials and highlight the importance of curvature in the design of resilient marine structures.

Vibration localization and reduction of double-plate structures

A thin plate-type resonator is attached to a host-stepped plate to achieve vibration localization and reduction in initial low-order global vibration modes. A semi-analytical method is proposed to analyze the free and forced vibrations of the double-plate structure, considering the geometric configuration's heterogeneity and discontinuity. The double plate structure is divided into several sub-plates for individual modeling, with admissible functions constructed for the displacements of each subdomain. These subdomains are then combined into a unified whole through displacement compatibility conditions. The no-orthogonality between global vibration and localized modes is determined using analytic mode functions obtained by the Ritz method with special admissible functions, which is crucial for suppressing the multiple resonance peaks of global vibration using the integrated plate-type resonator. An intriguing finding is that at the frequency veering point of global vibration modes and localized modes, the non-orthogonality can lead to two coupled global-localized modes that are similar to the initial localized mode, and the vibration of initial global modes can be mainly concentrated in the resonator region outside the plate during free vibration. For force vibration of the double plate, the initial resonance peak splits from one into two smaller resonance peaks due to the two coupled global-localized modes. Furthermore, the coupled global-localized mode allows for a substantial reduction in the host plate vibration while making a negligible impact on the total mass and global vibration frequency. This study presents a promising approach for reducing multimodal vibrations in lightweight structures.

Psychological research in vibration disease: level of alexithymia, psychological defenses

Vibration disease ranks among the first in the structure of diseases in workers at mechanical engineering enterprises, metallurgical, mining, and construction industries, various branches of agriculture, and aircraft manufacturing. A change in the mental status of people working in vibration conditions was identified; the most common are «neurosislike states» with psycho-emotional disorders of anxiety type. Meanwhile, currently existing data on the state of the nervous system in vibration pathology are contradictory and scarce, which requires a more in-depth study. Purpose of the study: to investigate the psychological status of patients with vibration disease from the action of both local and general vibration. Research results. In patients with vibration disease from the action of both local and general vibration, a predominance of destructive psychological defenses (projection and repression) over constructive ones (compensation and rationalization) is observed.

Research of upper limb tremor reduction with a vibrational medical device for Parkinson’s disease

Parkinson’s disease (PD) is a common neurodegenerative disease that manifests as a various movement disorders: tremor, rigidity and postural instability. These dysfunctions can significantly impact the individual’s quality of life, leading to a decline in overall well-being. However, recent innovations in medical devices field promise additional methods to alleviate PD symptoms. The VILIM Ball is a local hand-arm stimulation device that generates mechanical vibrations within the frequency range of 8–18 Hz. It was shown in this study that Parkinson’s disease patients (PD) may experience enhanced upper limb functionality and reduction in tremor power through physiotherapy in conjunction to therapy with VILIM Ball device. A total of 24 participants were recruited and divided into two groups: the control group (N= 12) underwent physiotherapy alone, while the experimental group (N= 12) received physiotherapy in combination with the VILIM Ball. Hand coordination, tremor power, and the right-hand grip strength before and after interventions were assessed to quantify the effects of the interventions. The right-hand tremor power decreased by an average of 7.38% for the control group and by an average of 48.11% for the experimental group. The left-hand tremor power increased by 3.89% for the control group and decreased by the 30.23% for the experimental group. There were no significant changes in the right-hand grip strength after the interventions. These findings indicate that the local hand-arm vibration provided by the VILIM Ball in conjunction to physiotherapy can benefit patients more than the physiotherapy alone.

Promoting Periodical Poling in Lithium Niobate Crystal Through Surface Acoustic Wave‐Induced Local Lattice Activation

AbstractAchieving precise construction of ferroelectric domain structure in lithium niobate (LN) crystals holds significance for expanding the applications of periodically poled lithium niobate (PPLN), especially in nonlinear frequency conversion. However, challenges exist during the application of electric field for poling, especially for small‐period PPLN crystals, where ferroelectric domains in LN crystals tend to unevenly expand laterally, making it hard to precisely control the domain structures. LN, as a piezoelectric crystal, has the capability to generate energy‐carrying surface acoustic waves (SAW). Herein, an method is presented to optimize the periodic poling process by integrating SAW and poling on a LN chip, which remarkably reduces the poling electric field by 10%, attributed to the enhanced local lattice vibrations during SAW propagation. The integrated SAW and poling chip achieves a 9 µm‐period PPLN crystal. Through second harmonic generation, a nonlinear light conversion from 1158 to 579 nm is realized, exhibiting a nonlinear optical efficiency up to 17.4%. This efficiency aligns with the theoretical prediction, validating the high‐quality domain structure. This integrated chip provides a unique opportunity for manipulating ferroelectric domain with high‐precision, benefiting a wide range of applications in nonlinear‐optics, ferroelectrics, and integrated optics.

Generation of quasi-traveling waves in a finite rectangular membrane with two internal viscoelastic line supports

In this work we study the forced vibration of a finite rectangular membrane driven by arbitrarily distributed boundary motion on two adjacent edges and internally coupled with multiple viscoelastic line supports, as an extension of the analysis of coexisting vibrations and waves in one-dimensional elastic strings and ducts. Using the static solution for the membrane displacement in the absence of interior supports, the response of the nonclassically damped system is obtained through a normal-mode expansion. A traveling-wave index based on complex orthogonal decomposition is utilized to identify and optimize the traveling waves in the rectangular membrane. A vibration localization condition in a semi-infinite membrane is analytically derived, from which the complex boundary excitations and constraints in a finite membrane are specified to effectively realize pure traveling waves and confine the vibration to a restricted area. Then the membrane is edge-driven by a simpler time-periodic, spatially sinusoidal excitation for practical realization, with the line-support parameters optimized using the traveling-wave index function and a derivative-free optimization routine with lower-bound constraints. Analytical results show that quasi-traveling waves are produced for ranges of line-support parameters (location, stiffness and damping) following optimization using the traveling-wave index. The developed wave patterns are examined with a power-flow analysis and numerically verified through finite element analysis. Wave localization is demonstrated to be valid in a finite membrane with specific boundary conditions and multiple viscoelastic line supports. The proposed method shows the predictive ability of the orthogonally stiffened membrane configuration as the basic unit cell for the design of periodic structures with directional wave propagation as well as vibration localization dynamics.

Large-bipolaron liquids in cuprate superconductors.

Uniquely, large-bipolarons' self-trapped holes occupy superoxygens, each comprising four oxygens circumscribed by four coppers in a CuO2 plane, formed as oxygens relax inward and coppers relax outward. Critically, concomitant oxygen-to-copper electron transfer eliminates copper spins. The d-symmetry of superoxygens' ground state molecular orbital tracks the superoxygens' predominant zero-point radial vibrations. These large bipolarons' distinctive charge transport, absorption, magnetism, local atomic vibrations, condensation into a liquid, and subsequent superconductivity are consistent with cuprate superconductors' long-established unusual properties.

Modelling and analysis of large periodic origami structures for local vibrations

In this paper, a novel framework is proposed for the structural analysis of large origami structures. The first order shear deformation theory of plates (FSDT) is employed to consider the stiffness of the origami facets and the folds stiffness is modeled via six linear and rotational springs at the intersections of the facets. The framework enables to predict the response of the entire elastic origami tessellation, by solving for the response of a unit cell under periodic boundary conditions. As a case study, a composition of four facets that its repetition forms the entire domain of Miura-ori tessellations is chosen as the unit cell. Then, the response is generated through solving a system of 20 linear-coupled PDEs subject to 80 boundary conditions. The results are generated numerically using generalized differential quadrature (GDQ) and finite element (FE) analysis. Via use of the framework, for the first time the effects of microstructure properties on the local vibration response of different Miura-ori tessellations are studied. Specifically, the effects of the base material, the facets geometry and the folds stiffness on the local vibration response of the structure are studied. Particularly, we show the existence of mode crossings (different mode shapes being excited with the same frequency) in the local vibration response of different Miura-ori unit cells that is highly affected by the microstructural characteristics. The results generated here can be used for designing and tailoring origami structures for high-end applications.

Role of chalcogen vacancies and hydrogen in the optical and electrical properties of bulk transition-metal dichalcogenides

Like in any other semiconductor, point defects in transition-metal dichalcogenides (TMDs) are expected to strongly impact their electronic and optical properties. However, identifying defects in these layered two-dimensional materials has been quite challenging with controversial conclusions despite the extensive literature in the past decade. Using first-principles calculations, we revisit the role of chalcogen vacancies and hydrogen impurity in bulk TMDs, reporting formation energies and thermodynamic and optical transition levels. We show that the S vacancy can explain recently observed cathodoluminescence spectra of MoS2 flakes and predict similar optical levels in the other TMDs. In the case of the H impurity, we find it more stable sitting on an interstitial site in the Mo plane, acting as a shallow donor, and possibly explaining the often observed n-type conductivity in some TMDs. We also predict the frequencies of the local vibration modes for the H impurity, aiding its identification through Raman or infrared spectroscopy.

Analysis and NDT applications of a gas discharge electroacoustic transducer

In this study, a gas discharge electroacoustic transducer (GDEAT) based on a pulsed electric discharge in the air under atmospheric pressure has been investigated. By evaluating acoustic pressure and recording amplitude-frequency characteristics of membranes, the acoustic characteristic of GDEATs have been obtained in the frequency range from 40 Hz to 4 MHz. The electro-thermo-acoustic processes have been studied in gas discharge systems of an open type where the electrode space is in a direct contact with the ambient. Some features of using the above-mentioned GDEATs in nondestructive testing (NDT) of materials have been demonstrated. It has been shown that, on one hand, the wear of both electrodes and insulation limits a work life of a transducer electrode system, but, from the other hand, this may lead to deposition of micro-particles on the surface of an object under test. The wear of electrode systems was evaluated quantitatively, and the results of the chemical analysis of deposited micro-particles have been presented. The use of a GDEATs for non-contact stimulation of local resonant vibrations in subsurface defects and visualizing vibrations by means of laser dopler vibrometry has been shown in the case of NDT of a glass fiber composite.

Non-drug therapies for patients with vibration disease associated with exposure to local vibration

Non-drug methods include acupuncture, the most effective way to regulate the body's energy system. Pulsed magnetic stimulation (PMS) is based on the application of the principles of electromagnetic induction, causes hyperpolarization or depolarization of nerve cells. The methods are practically not used in the clinic of occupational diseases, and their effectiveness in the treatment of vibration disease (VD) has not been established. The study aims to evaluate changes in the central nervous system and peripheral nerves, as well as in the psychological status of patients with vibration disease after sessions of acupuncture and pulsed magnetic stimulation. Using the acupuncture method, 24 male patients were treated with a diagnosis of VD associated with exposure to local vibration (average age 49.9±3.8 years, average length of service — 19.4±4.3 years), PMS — 24 people with a diagnosis of VD associated with exposure to local vibration (average age 48.8±3.4 years, average length of service — 18.1±3.4 years). The treatment methods performed made it possible to improve the quality of therapy, which was confirmed by a positive change in the indicators of visual and somatosensory evoked potentials, data from electroneuromyographic studies, vibration sensitivity and algesimetry, the state of the mnestic and attentional spheres of activity improved. The use of the acupuncture method allowed to improve the indicators of bioelectric activity of the brain: the amplitude of the peak N1 of visual evoked potentials increased (from 3.2 to 6.7 MV, p<0.05), the latency of the peak P200 decreased from 178.0 to 142.5 ms, p<0.05. The threshold of pain sensitivity on the zygomatic bone, on the phalanx of the 2nd finger of the hand and on the protruding part of the inner ankle decreased by 63, 125 and 250 Hz, p<0.05. Vibration sensitivity improved (on the ulnar process, phalanx of 2 fingers of the hand, p<0.01, on the tubercle of the tibia, p<0.05). Magnetic stimulation contributed to the improvement of cerebral changes in the treated patients — the latency of auditory evoked potentials decreased (p<0.03 for peak P1 and p<0.05 for peak P2), the amplitude of visual evoked potentials increased (p<0.05), the bioelectric activity of the occipital lobes of the brain increased. The duration of the afferent excitation wave at the level of the cervical region (latency N11 and N13, p<0.05) and thalamic structures (latency P25, p<0.05) increased. Non-drug therapy allowed to restore the time of excitation by the motor component of axons in patients on the upper extremities during acupuncture, on the upper and lower extremities during treatment with magnetic stimulation (p<0.05), improved indicators characterizing the mnestic-attentional and psychoemotional spheres of the treated. Ethics. Conclusion of the MEС of the Federal State Budgetary Scientific Institution "East Siberian Institute of Medical and Environmental Research" No. 32 dated 09/10/2019.

Intrinsically localized modes of bilinear FPU chains: Analytical study

Present study concerns the analysis of stationary intrinsically localized modes emerging in bilinear and symmetric Fermi–Pasta–Ulam chains. Each element of the chain is coupled to its nearest neighbors through identical and symmetric (tension/compression) bilinear springs. The intrinsically localized modes are the time-periodic, localized vibration states which are manifested by the extreme energy localization on one and two bonds of the chain for bond - centered and site - centered symmetries, respectively. Approximate and exact analytical solutions of intrinsic localized modes are derived for the infinite as well as the finite chains, correspondingly. The derived analytical approximations allow to describe explicitly the amplitude wave profiles of these special localized states as well as to establish their zones of existence in the space of system parameters. In the second part of the study, we derive the exact analytical solutions for the same type of site- and bond- centered intrinsically localized modes supported by the finite bilinear Fermi–Pasta–Ulam chains and analyze their stability properties using Fillipov method.