Frequency Mechanical Vibration Research Articles

Strengthening effect of mechanical vibration on the carbonation properties of steel slag compact

This study examines the impact of mechanical vibration on the carbonation process of steel slag, a substantial byproduct of steel production. Employing a methodical experimental design that modulates mechanical vibration frequencies, the research reveals that mechanical vibration markedly influences carbonation, with an optimal frequency of 180 Hz leading to a 27.5 % increase in compressive strength of steel slag compact and an increase in CO2 uptake of 6.8 %. The application of vibration appears to catalyze the conversion of calcium-rich minerals into well-formed rhombohedral calcite, which emerges as the predominant carbonation product. Mechanism analysis suggests that vibration-induced particle redistribution creates new reaction surfaces, thereby accelerating the carbonation process. However, the effect is more pronounced in early stages, with diminishing returns as carbonation progresses. These pivotal findings propose an innovative strategy to augment the efficiency of carbonation and the inherent material properties of steel slag, thereby fostering a more sustainable approach to the utilization of industrial byproducts.

The impact of mechanical vibration at cathode on hydrogen yields in water electrolysis

This study investigates the utilization of mechanical vibration to enhance the hydrogen evolution reaction (HER) in electrolysis processes. By varying the force magnitude and frequency of mechanical vibration, significant improvements in HER efficiency were observed. Specifically, the mechanical vibration-assisted electrolysis with a hitting frequency of 3 hits per second and 157.2698 Kg. m−2 hitting force improved the HER current density by 128 % compared to untreated water electrolysis. Linear sweep voltammetry (LSV) data for the graphite electrode revealed a distinct reduction peak at 1 V, indicating a favorable electrochemical reduction reaction influenced by mechanical vibration. The frequency of mechanical vibration significantly impacted the LSV response, with variations in current values across different conditions. Mechanistically, mechanical vibration disrupted intermolecular forces, facilitating better electrode-bubble interactions and accelerating reaction kinetics. Additionally, changes in pH levels induced by mechanical vibration further enhanced HER efficiency. These results suggest that integrating mechanical vibration into electrolysis systems significantly improves HER performance, contributing to the advancement of more efficient and sustainable hydrogen production technologies, which are crucial for achieving net-zero emission targets.

Control of Vibratory Feeder Device Mechanical Frequency Using the Modification of the Sinusoidal Supply Voltage Signal

In the industrial and sales processes, dosing systems of various constructions, whose operation is based on mechanical vibrations (vibratory feeders), are very often used. These systems face many problems, such as resonant frequency, flow instability of dosed product, instability of mechanical vibration amplitude, etc., because most of them are based on controlling the frequency of the electrical signal of the supply voltage. All these factors negatively affect the durability and reliability of the vibratory feeder systems. During this research, an automatic control system for vibratory feeder was created, whose control process is based on the modification of the sinusoidal signal (partially changing the signal area). In addition, such a way of controlling the vibratory feeder is not discussed in the literature. As the research conducted in this paper has shown, while using sinusoidal signal modification it was possible to achieve a stable flow rate of bulk production (the flow rate varied from 0 to 100 g/s when the frequency of mechanical vibrations changed from 1 to 50 Hz) and a stable amplitude of mechanical oscillations was achieved and equal to 1.5 mm. The control system is based on the microcontroller PIC24FV32KA302 for which the special software was developed. The thyristor BTA16 used for voltage modification of the sinusoidal signal made it possible to ensure the reliable control of the sinusoidal voltage modification process.

An Automatic Frequency Control System for Transmission Machinery Based on Back-Propagation Neural Network Algorithm in the Internet of Things Environment

Abstract In order to reduce the error of automatic frequency control of transmission machinery under different disturbances, an automatic frequency control system of transmission machinery based on back-propagation (BP) neural network algorithm is designed. The gradient descent method and Newton method are combined to optimize the BP neural network. Aiming at the periodicity and trend of the actual mechanical vibration frequency time series, the first order backward difference is processed by the difference method, and the autoregressive sequence is derived to obtain the control model. The experimental results show that the system can realize the automatic control of transmission mechanical frequency with small error under different types of interference, and the control effect is ideal.

Excitation of Josephson Currents by Aerogel Vibrations in Superfluid <sup>3</sup>He

The problem of mechanical vibrations of an aerogel attached to an elastic wire in superfluid3He is solved for the case, where the aerogel is also in a superfluid state. The hydrodynamic boundary conditions at the aerogel surface formulated in this work allow one to explain the anomalously rapid increase in the frequency of mechanical vibrations of the system on cooling. The found relation between the phase jump at the aerogel boundary and the superfluid current flowing across the boundary suggests the Josephson character of such current.

Computational simulation of applying mechanical vibration to mesenchymal stem cell for mechanical modulation toward bone tissue engineering.

Evaluation of cell response to mechanical stimuli at in vitro conditions is known as one of the important issues for modulating cell behavior. Mechanical stimuli, including mechanical vibration and oscillatory fluid flow, act as important biophysical signals for the mechanical modulation of stem cells. In the present study, mesenchymal stem cell (MSC) consists of cytoplasm, nucleus, actin, and microtubule. Also, integrin and primary cilium were considered as mechanoreceptors. In this study, the combined effect of vibration and oscillatory fluid flow on the cell and its components were investigated using numerical modeling. The results of the FEM and FSI model showed that the cell response (stress and strain values) at the frequency of mechanical vibration has the highest value. The achieved results on shear stress caused by the fluid flow on the cell showed that the cell experiences shear stress in the range of . Mechanoreceptors that bind separately to the cell surface, can be highly stimulated by hydrodynamic pressure and, therefore, can play a role in the mechanical modulation of MSCs at in vitro conditions. The results of this research can be effective in future studies to optimize the conditions of mechanical stimuli applied to the cell culture medium and to determine the mechanisms involved in mechanotransduction.

Microstructure and performance enhancement of the TiN/Fe-based cladding layer induced by mechanical vibration assisted underwater wet laser cladding

It is challenging to obtain the underwater wet laser cladding layer with excellent properties while maintaining formability. In this paper, the method of using synchronous mechanical vibration assisted in the underwater wet laser cladding process of TiN/Fe-based cladding layer was introduced. The effect of mechanical vibration frequency on the dilution rate, microstructure, corrosion resistance, tribo-corrosion behavior of the cladding layer was studied. The result displayed that with increase of mechanical vibration frequency, the dilution effect of the substrate was obviously weakened and the phase changed from ferrite to ferrite and austenite, and TiN particles were evenly distributed. In addition, the grain size of the cladding layer showed a tendency to decrease first and then increase. When the mechanical vibration frequency was 400 Hz, the grain refinement phenomenon was the most obvious and the average grain size was 8.39 μm. Based on the effect of dispersion strengthening and fine grain strengthening, the microhardness and wear resistance of the cladding layer assisted at 400 Hz were improved, and the wear rate was 1.17 × 10−15m3N−1 m−1. While the cladding layer assisted at 400 Hz exhibited better corrosion resistance by forming a dense passivation film. In addition, the mechanism of mechanical vibration on microstructure evolution and performance enhancement of the cladding layer was also analyzed. This study provided the theoretical support for the formability of the underwater laser wet cladding assisted by mechanical vibration.

Effect of mechanical vibration on heat and mass transfer performance of pool boiling process in porous media: a literature review

Pool boiling in porous media has been applied in various thermal management systems by using latent heat and increasing the heat transfer area and thermal conduction path to improve the heat transfer performance. In mechanical equipment, vibration is an inevitable problem due to reasons such as engine operation and high-speed relative motion between transmission system components, which causes the system components to be affected by vibration forces or vibration accelerations. This study focuses on a review of published articles about the effects of mechanical vibration on the characteristics of boiling process in porous media by two aspects: heat transfer performance and bubble dynamics. Heat transfer coefficient (HTC) and critical heat flux are two main parameters used to measure the boiling heat transfer characteristics of porous media. For bubble dynamics investigations, properties such as migration, fragment, coalescence, departure diameter and frequency are the focus of research attention. Different mechanical vibration parameters, i.e., direction, frequency, and amplitude, will have different effects on the above characteristics. It is worth mentioning that the greatest influence occurs under resonance conditions, and this has been verified through experimental and simulation calculations. This review highlights the importance of considering mechanical vibrations in the design and optimization of porous media systems for efficient heat transfer applications. Further research is warranted to explore the detailed mechanisms and optimize the vibration parameters for enhanced heat transfer performance in thermal management systems using porous media.

Excitation of Josephson Currents by Aerogel Vibrations in Superfluid 3He

The problem of mechanical vibrations of an aerogel attached to an elastic wire in superfluid 3He is solved for the case, where the aerogel is also in a superfluid state. The hydrodynamic boundary conditions at the aerogel surface formulated in this work allow one to explain the anomalously rapid increase in the frequency of mechanical vibrations of the system on cooling. The found relation between the phase jump at the aerogel boundary and the superfluid current flowing across the boundary suggests the Josephson character of such current.

Effect of Whole-body Vibration frequency on muscle tensile state during graded plantar flexor isometric contractions

BackgroundAcute physiological and biomechanical alterations have been reported following whole-body vibration (WBV). Stiffening of muscles has only been anecdotally reported in response to WBV. Accordingly, this study investigated active plantar flexor muscle stiffness in response to a single WBV bout at four mechanical vibration frequencies. MethodsThirteen healthy adults (37.1 ± 14.4 years old) randomly received WBV in 4 different frequencies (6, 12, 24, and 0 Hz control) for 5 min. Shear wave speed (SWS) in longitudinal and transverse projections, architecture, and electric muscle activity were recorded in the medial gastrocnemius (MG) and soleus (SOL) muscle during graded plantar flexor contraction. Subjective rating of perceived muscle stiffness was assessed via Likert-scale. ResultsSWS of the MG at rest was enhanced in response to 5 min of 24 Hz WBV (p = 0.025), while a small reduction in SOL SWS was found during contraction (p = 0.005) in the longitudinal view. Subjective stiffness rating was increased following 12 Hz intervention. After 24 Hz WBV, pennation angle for MG was decreased (p = 0.011) during contraction. As a secondary finding, plantar flexor strength was significantly increased with each visit, which, however, did not affect the study's main outcome because of balanced sequence allocation. ConclusionSWS effects were solely limited to 24 Hz mechanical vibration and in the longitudinal projection. The observed effects are compatible with an interpretation by post-activation potentiation, warm-up, and force-distribution within the triceps surae muscles following 5 min WBV. The outcome may suggest SWS as a useful tool for assessing acute changes in muscle stiffness.

Effect of doping on vibration frequency of graphene nanoribbons

Graphene has excellent mechanical properties and vibration frequency is an important mechanical property. In this paper, the effects of doping elements and doping concentrations on the vibration characteristics of graphene nanoribbons were investigated by molecular dynamics simulation. The vibration characteristics are influenced by the doping element, depending on the bond structural difference in bond structure between doping atoms and carbon atoms. The vibration frequencies of Nitrogen (N)-doped and Nitrogen–Nitrogen (N–N)-doped graphene nanoribbons are slightly lower than those of pure graphene nanoribbons. However, the vibration frequencies of Sulfur (S)/Phosphorus (P)-doped and Sulfur–Sulfur (S–S)/Phosphorus–Phosphorus (P–P)-doped graphene nanoribbons are significantly lower than those of pure graphene nanoribbons. In addition, with the increase of S (P) doping concentration, the vibration frequency of monolayer graphene nanoribbons decreases gradually.

Study of coupled waves of cylinder walls and internal liquid based on cylindrical shell theory and wave equation

In the present study, we focus on coupled waves of cylinder walls and an internal liquid, one of the important issues in various fluid machinery including nuclear reactors. The main objective of this study is to propose a novel method to predict coupled wave frequencies based on the cylindrical shell theory and wave equation with the consideration of the fluid added mass. First, we introduce the fluid added mass to consider the effects of the liquid mass. Second, we discuss the vibration behavior of cylinder walls and sound propagation of an internal liquid separately to describe the coupled wave theoretically. In this discussion, we derive dispersion relations of the cylinder walls and internal liquid based on the Flügge’s cylindrical shell theory and wave equation in the cylindrical coordinates, respectively. To validate our proposed theory, we conduct an experiment on the coupled waves using a SUS304 pipe as a cylinder and water as an internal liquid. As a result of frequency analysis based on the power spectral density (PSD), we confirm that the coupled waves occur without any external vibration sources, and the vibration modes and the most prominent vibration mode vary with the flow rate of the internal water. Also, theoretical values of coupled wave frequencies consistently agree with experimental values. This result demonstrates that coupled wave frequencies can be predicted correctly using dispersion relations of cylinder walls and an internal liquid derived based on the cylindrical shell theory and wave equation with the consideration of the fluid added mass. The prediction of coupled wave frequencies for liquid-filled structures by our proposed method leads to the prevention of significant levels of vibrations and noises by making a difference between coupled wave frequencies and mechanical vibration frequencies.

Effects of mechanical vibration on bone – a critical review

The benefits of reduced treatment time and comfort for patients undergoing corrective dental treatment with devices gave rise to the creation and modification of long-standing treatment protocols. One of the protocols used for these purposes is mechanical vibration. Objective: This review aimed to study the effects of mechanical vibration on bone. Methods: Portal Capes (periodicos.capes.gov.br) database was searched using the keywords “vibration” and “bone” with no date limit. Based on the title and abstract, the first 50 relevant studies were retrieved. The measured frequencies were between 4 and 150 Hz. Regarding exposure time and the number of applications, the variation is so wide that the average or median would not represent a realistic sample pattern. Results: In the retrieved studies, 41 reported improvements in bone conditions. Research studies show that a reproducible protocol is being applied in most studies on the effects of mechanical vibration on bone tissue. Conclusion: There is stimulation of bone biology, regardless of species, in the sense of osteogenesis in individuals exposed to high frequency mechanical vibration. To improve research protocols on the effects of vibrations on the body, more studies are needed.

Auditory clicks elicit equivalent temporal frequency perception to tactile pulses: A cross-modal psychophysical study.

Both hearing and touch are sensitive to the frequency of mechanical oscillations—sound waves and tactile vibrations, respectively. The mounting evidence of parallels in temporal frequency processing between the two sensory systems led us to directly address the question of perceptual frequency equivalence between touch and hearing using stimuli of simple and more complex temporal features. In a cross-modal psychophysical paradigm, subjects compared the perceived frequency of pulsatile mechanical vibrations to that elicited by pulsatile acoustic (click) trains, and vice versa. Non-invasive pulsatile stimulation designed to excite a fixed population of afferents was used to induce desired temporal spike trains at frequencies spanning flutter up to vibratory hum (>50 Hz). The cross-modal perceived frequency for regular test pulse trains of either modality was a close match to the presented stimulus physical frequency up to 100 Hz. We then tested whether the recently discovered “burst gap” temporal code for frequency, that is shared by the two senses, renders an equivalent cross-modal frequency perception. When subjects compared trains comprising pairs of pulses (bursts) in one modality against regular trains in the other, the cross-sensory equivalent perceptual frequency best corresponded to the silent interval between the successive bursts in both auditory and tactile test stimuli. These findings suggest that identical acoustic and vibrotactile pulse trains, regardless of pattern, elicit equivalent frequencies, and imply analogous temporal frequency computation strategies in both modalities. This perceptual correspondence raises the possibility of employing a cross-modal comparison as a robust standard to overcome the prevailing methodological limitations in psychophysical investigations and strongly encourages cross-modal approaches for transmitting sensory information such as translating pitch into a similar pattern of vibration on the skin.

On the Efficiency Enhancement of an Actively Tunable MEMS Energy Harvesting Device

In this paper, we propose an active control method to adjust the resonance frequency of a capacitive energy harvester. To this end, the resonance frequency of the harvester is tuned using an electrostatic force, which is actively controlled by a voltage source. The spring softening effect of the electrostatic force is used to accommodate the dominant frequency of the ambient mechanical vibration within the bandwidth of the resonance region. A single degree of freedom is considered, and the nonlinear equation of motion is numerically integrated over time. Using a conventional proportional–integral–derivative (PID) control mechanism, the results demonstrated that our controller could shift the resonance frequency leftward on the frequency domain and, as a result, improve the efficiency of the energy harvester, provided that the excitation frequency is lower than the resonance frequency of the energy harvester. Application of the PID controller in the resonance zone resulted in pull-in instability, adversely affecting the harvester’s performance. To tackle this problem, we embedded a saturation mechanism in the path of the control signal to prevent a sudden change in motion amplitude. Outside the pull-in band, the saturation of the control signal resulted in the reduction of harvested power compared to the non-saturated signal; this is a promising improvement in the design and analysis of energy harvesting devices.

Tactile Low Frequency Vibration in Dementia Management: A Scoping Review.

The prevalence of dementia is increasing with the ever-growing population of older adults. Non-pharmacological, music-based interventions, including sensory stimulation, were reported by the Lancet Commission in 2020 to be the first-choice approach for managing the behavioural and psychological symptoms of dementia. Low frequency sinusoidal vibration interventions, related to music interventions through their core characteristics, may offer relief for these symptoms. Despite increasing attention on the effectiveness of auditory music interventions and music therapy for managing dementia, this has not included low frequency vibration. This scoping review, following the JBI methodology guidelines, was conducted to investigate participants’ responses to both sound and mechanical vibration, the characteristics of the delivered interventions, methodological challenges, and the specifics of the research experiments reported. An extensive search was conducted in BMC, CINAHL, Cochrane Central Register of Controlled Trials, EMBASE, ERIC, MEDLINE (OvidSP), Pedro, ProQuest Central, PsycINFO, Scopus, and Web of Science. Current Controlled Trials, Clinical Trials, and Google Scholar were also searched as well as a hand search in relevant journals. Studies on adults with all types of dementia, investigating tactile low frequency sound or mechanical vibration in any context were considered. Data from eight full-length studies (three RCTs, two quasi-experimental, two case reports, and one qualitative) were extracted using the data extraction table developed by the authors and were included in the analysis and critical appraisal. Issues in quality related to, for example, control groups and blinding. Few studies addressed participants’ subjective responses to the interventions. Reporting on the intervention characteristics was unclear. It appeared more frequent sessions led to better outcomes and home-based interventions potentially addressing the issue of access and feasibility. Future research should include neuroimaging to measure and confirm the hypothesised mechanism of cerebral coherence. Standardised reporting of intervention characteristics is also needed to ensure replicability of the experiments. Higher quality research is needed to investigate the impact and effect of low frequency vibration for the symptoms of dementia and compare outcomes in meta-syntheses.

Harmonic Scalpel versus Electrocautery: An Experience of Modified Radical Mastectomy at Tertiary Care Teaching Hospital

Background: The harmonic scalpel, commonly used in laparoscopic surgery, now has promise for MRM dissection. The harmonic scalpel's high frequency mechanical vibrations cut and coagulate intraoperatively at the same time, generating less heat injury than electrocautery.
 Objective: To compare the outcome of modified radical mastectomy using harmonic scalpel versus electrocautery at tertiary care teaching hospital.
 Methodology: The randomized controlled trial was conducted from 12th September 2018 11th March 2019 at Department of Surgery, Liaquat University of Medical and Health Science, Jamshoro. A total of 128 patients with infiltrating ductal carcinoma undergoing modified radical mastectomy, 20 to 50 years of age were included. Chronic Hepatitis, diabetes, and neo-adjuvant treatment patients were excluded. Modified radical mastectomy employing harmonic scalpel for Group A and electrocautery for Group B. Postoperative problems such as seroma development, postoperative hematoma, marginal necrosis, lymphedema, and wound infection were also observed.
 Results: The mean age of women in group A was 39.81 ± 6.73 years and in group B was 39.45 ± 6.60 years. Mean duration of disease was 5.41 ± 1.91 months. The frequency of seroma formation in harmonic scalpel group as 7.81% vs 26.56% in electrocautery group, p=0.005), frequency of pain is 53.13% vs 68.75% respectively, p=0.070, frequency of hematoma is 1.56% vs 17.19% respectively, p=0.002), frequency of marginal necrosis was 0.0% vs 7.81% respectively, p=0.023), lymphedema 3.13% vs 14.06% respectively, p=0.027) and wound infection 17.19% vs 35.94% respectively, p=0.016.
 Conclusion: This research indicated that harmonic scalpel is superior to electrocautery in modified radical mastectomy.

Multipoint monitoring of amplitude, frequency, and phase of vibrations using concatenated modal interferometers

Concatenated modal interferometers-based multipoint monitoring system for detection of amplitude, frequency, and phase of mechanical vibrations is proposed and demonstrated. The sensor probes are fabricated using identical photonic crystal fiber (PCF) sections and integrated along a single fiber channel to act as a compact and efficient sensing system. Each identical probe acts as a modal interferometer to generate a stable interference spectrum over the source spectrum. In the presence of an external dynamic field about each probe, the probes respond independently, producing a resultant signal superposition of each interferometer response signal. By analyzing the resultant signals using computational techniques, the vibration parameters applied to each interferometer are realized. The sensing system has an operation range of 1 Hz-1 kHz with a sensitivity of 51.5 pm/V. Such a sensing system would find wide applications at industrial, infrastructural, and medical fronts for monitoring various dynamic physical phenomena.

High speed time-of-flight displacement measurement based on dual-comb electronically controlled optical sampling.

We demonstrate a direct time-of-flight approach that utilizes dual-comb electronically controlled optical sampling (ECOPS) to measure small displacements. ECOPS is enabled by electrically controlling the repetition rate of one laser via an intracavity electric-optical modulator (EOM). The acquisition rate is set by the EOM modulation frequency, which is much higher than commonly used asynchronous optical sampling (ASOPS). In a proof-of-principle experiment, an 80-kHz acquisition rate is obtained with a pair of ∼105 MHz repetition rate Er-fiber lasers. At an average time of 30 ms, a measurement precision evaluated with Allan deviation reaches 26.1 nm for a 40-µm static displacement. In a dynamic measurement, a 500-Hz sinusoidal vibration with 15 µm amplitude has also been identified. The high-precision and high-speed displacement measurement technique can be potentially used in 3D surface profilometry of microelectronic step-structures and real-time monitoring of high frequency mechanical vibrations, etc.

The Investigation of Forward and Backward Brillouin Scattering in High-Q Chalcogenide Microspheres

Traditional optomechanical research is rarely studied in compound glass, especially chalcogenide glass. In this paper, the forward and backward Stimulated Brillouin Scattering (SBS) is demonstrated for the first time in a chalcogenide glass microsphere resonator. A high-purity chalcogenide glass microsphere with a high quality (<i>Q</i>) factor of 2.1 &#x00D7; 10⁷ is investigated using a 1550 nm tunable laser. In the experiment, the resulting mechanical vibration frequencies caused by forward and backward SBS are measured at 80 MHz and 7.8 GHz, respectively. The triply resonant Stimulated Brillouin scattering process greatly enhances the light&#x2013;acoustic interactions, enabling the threshold power to be 344 &#x03BC;W. The work demonstrated in the chalcogenide microresonator is important for the potential applications of chalcogenide glass, which has higher nonlinearity and low absorptions at mid-infrared band.