Different Frequencies Of Vibration Research Articles

Sound-to-Touch Crossmodal Pitch Matching for Short Sounds.

This article explores how to relate sound and touch in terms of their spectral characteristics based on crossmodal congruence. The context is the audio-to-tactile conversion of short sounds frequently used for user experience improvement across various applications. For each short sound, a single-frequency amplitude-modulated vibration is synthesized so that their intensive and temporal characteristics are very similar. It leaves the vibration frequency, which determines the tactile pitch, as the only variable. Each sound is paired with many vibrations of different frequencies. The congruence between sound and vibration is evaluated for 175 pairs (25 sounds × 7 vibration frequencies). This dataset is employed to estimate a functional relationship from the sound loudness spectrum of sound to the most harmonious vibration frequency. Finally, this sound-to-touch crossmodal pitch mapping function is evaluated using cross-validation. To our knowledge, this is the first attempt to find general rules for spectral matching between sound and touch.

Comparative Effects of Percussion Theragun Versus Physical Activity in Non-Specific Neck Pain in Young Adults – A Randomized Clinical Tr

Background: The percussion theragun uses fast oscillatory back and forth movements to produce vibrations of different frequencies. Handheld percussive massage treatment has acquired fame as of late, for both remedial use and in sports practice. Physical activity is any movement that uses energy that improves strength, flexibility. With both the possible treatment options, the study raises the question of which of the two produces better results in subjects with Non-specific neck pain in terms of reduction of pain and increase in range. The objective of this study was to assess and compare the therapeutic effects of the percussion theragun with physical activity for the treatment of non-specific neck pain. Method and Measures: The study was conducted on 36 subjects with non-specific neck pain who were given 3 consecutive sessions (in a span of 3 days) of intervention. Through randomized method subjects were divided into the percussion theragun group (group A) and conventional physical activity group (group B). Outcome measures such as VAS (visual analogue scale) and Neck range of motion were assessed Results: The nonspecific neck pain participants in Group A and Group B showed significant improvement in extension, right lateral flexion, left lateral flexion neck ROM and reduction in VAS after exposed to the respective intervention. However, the Group A showed a significant improvement in VAS and ROM when compared with Group B. Conclusion: The current study provided the evidence to prove that the protocols used in this study show significant reduction in pain and range of motion in subjects with non-specific neck pain in both the groups. The percussion theragun group showed significantly greater improvement than the physical activity group.

AN INNOVATIVE DEVICE FOR TMJ VIBRATION ANALYSIS

Temporomandibular joint (TMJ) sounds are an important sign of temporomandibular disorder. Vibrations of different frequencies have been linked to certain types of disorders of the TMJ. Commercially available instrumentsemployed to record the vibrations of the TMJ are expensive and impractical to purchase in a clinical setup or for educational purposes. This article describes the development of a novel, innovative and inexpensive device using a pair of accelerometers, microphones and smartphones along with a developed software for the purpose of recording and analysing the recorded data from the TMJ.

Analysis of the Impact of Vibrations on a Micro-Hydraulic Valve Using a Modified Induction Algorithm

This paper addresses the impact of mechanical vibrations of different frequencies on a particular type of valve. It has been shown that a neural network can be used to compress measurement data and determine the frequency range that is most important in describing the impact of mechanical vibrations on a micro-hydraulic overflow valve. Later, induction decision trees were used for the generated areas, determining key measurement points. The most important areas of dependence are determined using inductive decision trees in induction. The entropy measure is used to determine the most significant attribute. A modified induction algorithm was used for the comprehensive analyses. The analysis carried out in the paper identified the intervals in which the flow rate plays a decisive role for the entire amplitude and frequency spectrum. An analysis was performed for the 200…900 [Hz] frequency interval of the external driving force, with a harmonic step of 10 [Hz]. The analysis was performed while considering these main valve parameters: the pressure of the overflow valve opening p = 10 [MPa]; flow rate in the valve: 0.6, 0.8 and 1 [dm3/min]; stiffness of valve spring c = 7.49 [N/mm]. Plots were presented and for each plot, the most important four intervals were determined. They are hierarchically ordered in the interval range of the whole frequency spectrum range: (coefficient IV)—the most important; (coefficient III)—important; (coefficient II)—less important; (coefficient I)—least important. A test rig and the results of a study on the effect of mechanical vibration on changes in the amplitude-frequency spectrum of pressure pulsations of a micro-hydraulic system, in which a micro-hydraulic relief valve was subjected to mechanical vibration, are presented.

Flow Dynamics and Acoustics from Glottal Vibrations at Different Frequencies

Glottal vibration is fundamental to breathing-related disorders and respiratory sound generation. However, responses of the flow and acoustics to glottal vibrations of different frequencies are unclear. The objective of this study is to numerically evaluate the influences of glottal vibration frequencies on inspiratory airflow dynamics and flow-induced sound signals; this is different from normal phonation that is driven by controlled expiratory flows. A computational model was developed that comprised an image-based mouth–throat–lung model and a dynamic glottis expanding/contracting following a sinusoidal waveform. Large Eddy simulations were used to solve the temporal and spatial flow evolutions, and pressure signals were analyzed using different transform algorithms (wavelet, Hilbert, Fourier, etc.). Results show that glottal vibrations significantly altered the flows in the glottis and trachea, especially at high frequencies. With increasing vibration frequencies, the vortices decreased in scale and moved from the main flow to the walls. Phase shifts occurred between the glottis motion and glottal flow rates for all frequencies considered. Due to this phase shift, the pressure forces resisted the glottal motion in the first half of contraction/expansion and assisted the glottal motion in the second half of contraction/expansion. The magnitude of the glottal flow fluctuation was approximately linear with the vibration frequency (~f0), while the normal pressure force increased nonlinearly with the frequency (~f01.85). Instantaneous pressure signals were irregular at low vibration frequencies (10 and 20 Hz) but became more regular with increasing frequencies in the pressure profile, periodicity, and wavelet-transformed parameters. The acoustic characteristics specific to the glottal vibration frequency were explored in temporal and frequency domains, which may be used individually or as a combination in diagnosing vocal fold dysfunction, snoring, sleep apnea, or other breathing-related diseases.

Effect of Ultrasonic Vibration Frequency on Ni-Based Alloy Cladding Layer

In order to maximize the performance of the nickel-based cladding layer without adding a reinforcing phase, ultrasonic vibrations of different frequencies are assisted in the laser cladding process. The morphology of the cladding layer was analyzed by a metallographic microscope, the microstructure of the cladding layer was analyzed by SEM, the element segregation of the cladding layer was analyzed by EDS energy spectrum, and the microhardness of the cladding layer was tested by a microhardness tester. Hardness and friction-wear performance of the cladding layer were tested using a friction and wear tester. The test results show that the appropriate ultrasonic frequency can obviously refine the microstructure of the cladding layer, the hardness and wear resistance of the cladding layer have been significantly improved due to the refinement of the structure, and it has a good fine grain for the cladding layer. The strengthening effect maximizes the performance of the cladding layer.

Investigation of the Relationship between Vibration Signals Due to Oil Impurity and Cavitation Bubbles in Hydraulic Pumps

Although hydraulic pumps are frequently used in daily life, improper use due to oil analysis or oil contamination is ignored. There is no instantaneous inspection; instead, the oil is changed periodically at certain times, whether it is contaminated or not. Hydraulic systems operate based on Pascal’s law, which states that the fluid will distribute the pressure equally to every point in a closed area. The fluid oil taken from an oil reservoir is moved into the pump by engine power. During this movement, as it passes through different pressure areas and different sections, undesirable events such as viscosity change and gas formation occur in the hydraulic oil. These formations collide with the outer walls and cause cavitation with respect to unwanted oil impurities. This cavitation causes unwanted vibration signals to occur in the normal working order of the system. As a result of cavitation, the particles that affect the lubricity and fluidity of the oil in the oil are mixed into the liquid and circulate freely. At the connection points, the blockage caused by the liquid in the pump cylinder block or the valve plate and the collisions of particles is effective. As a result, it creates vibrations of different frequencies. The frequency and amplitudes of these vibrations differ according to the degree of oil contamination. A method has been developed to find the degree of contamination of the oil circulating in the pump by looking at the amplitude and frequency of these vibrations measured from the motor body. There exist standards about the pollution of hydraulic fluid. With these standards, the maximum number of particles allowed for a given pollution level is defined. This topic is discussed in the conclusion to this study. This method has also been proven experimentally. Error and vibration analysis studies on pumps using a different approach are available in the literature. In these studies, pressure variation, total energy transmission, or artificial intelligence models were used to detect anomalies in the pump. In this study, the impurity rate of the oil was set at five different levels and the operating regime of the pump at each level was investigated experimentally. Rayleigh–Plesset and Zwart–Gerber–Belamri models, which are the most common cavitation models, were used to explain the bubble formation in the moving oil and the relationship of these bubbles with vibration. Frequency components were examined by the Discrete Fast Fourier Analysis method, where the operation of the pump was affected by the increase in oil impurity.

Monitoring the technical condition of the main mine hoist

Introduction. Ensuring the safe operation of skip and cage hoisting installations is one of the most important tasks of theoretical and experimental research in the field of mining mechanics. To achieve this goal, predictive (proactive) maintenance is required. It consists in performing the necessary repair actions to reduce the rate of development or prevent malfunctions identified on the basis of information about the actual technical condition of the equipment. Proactive maintenance is based on monitoring the technical condition of an object, it is the most effective in terms of preventing failures and the least expensive. Methods of research. The most important physical and mechanical properties of the components of hoisting equipment from the point of view of the reliability of their functioning are the endurance of critical parts and metal structures. To implement the monitoring system, sensors are needed to obtain the most reliable information for predicting changes in the physical and mechanical properties of loaded elements. The task of assessing the technical state from the stresses acting in the material is complicated by the cyclical nature of the load. The disadvantage of the widely used method for determining stresses by measuring the deformation with a tensometer with subsequent calculation is that the stresses are obtained indirectly with inevitable errors. An error arising from the impossibility of taking into account the actual nature of the loading is added to the error associated with calculating values from analytical dependencies. Results. In the monitoring system, it is advisable to use integral-type film strain gauges, which make it possible to predict the destruction of a part by detecting microcracks on its surface. Conclusion. The load on the monitoring objects is the result of the addition of vibrations of different frequencies and amplitudes, and integral-type film strain gauges will make it possible to obtain the most reliable information about the state of critical parts of mechanisms and metal structures.

Research of the impact of vibration on the efficiency of dissemination of loose plant products from the motor vehicle bodies

The object of research is the process of unloading bulk crop products from the bodies of dump trucks, the subject of the study is the dependence of the energy consumption of unloading on the properties of products when exposed to vibration. This dependence is understood as a change in the properties of bulk products, such as internal friction and the angle of repose, in the direction of decreasing, providing a decrease in the angle of lift of the body. One of the most problematic areas is the lack of objective information on the dependence of the required lifting angles of the dump truck body when unloading fine-grained crop products when exposed to vibrations. There is also insufficient information on the dependence of these angles on vibration frequency for each of the products. In the course of the study, an experimental method was used to determine the angles of natural bevel for different crops without and under the influence of vibrations of different frequencies on the reference area. The proposed development makes it possible to quantitatively assess the degree of influence of vibrations, their frequencies and time of impact on the frictional properties of bulk crop products. The degree of reduction of internal friction in these products and the maximum angles of lifting the body required for its unloading were experimentally determined, and numerical data were obtained on their reduction under the influence of vibrations. The results obtained allow to consider it an effective tool for obtaining objective information about the effect of vibrations on the characteristics of internal friction of bulk crop products. This made it possible to determine the degree of influence of the lift angle of the dump truck body during unloading and to reduce energy costs. In contrast to the existing ones, the proposed development makes it possible to differentiate these angles depending on the frequency and time of exposure to vibration, as well as on a specific product. Certain parameters make it possible to regulate them to achieve minimum energy consumption.

Numerical and Experimental Study on the Influence of Low Frequency Vibration on Strains of Single Point Incremental Forming

Single point incremental forming (SPIF) is a decent potential procedure appropriate for small batch production. In addition to that, the formability of the material is expanded compared to the other sheet metal forming processes. Meanwhile, the more advanced SPIF process requires perfect comprehension of the material deformation technique. In this paper, the equipment of vibration - sheet metal forming was designed. Finite element model was used to demonstrate and analyze the effect of different frequencies of vibration on the strain distribution in single point incremental forming process. The results show that specific vibration parameters can decrease strain. Moreover, an experimental vibration system using single point incremental forming was designed. The numerical model is primarily supported by test results conclusions from a simple cone of Al1050 aluminum alloy.

Sensitivity Enhancement of Electrochemical Biosensor for Point of Care (POC) Applications: Vi Antigen Detection as a Case Study

A novel approach for signal enhancement of electrochemical biosensors by incorporating mechanical vibrations has been developed. We report the electrochemical study of the ferricyanide and ferrocyanide a redox couple, at room temperature (∼25 °C), under the effect of mechanical vibrations of different frequencies applied to the sensor, for sensitivity enhancement. The experimental results showed a sensitivity enhancement of ∼332% (from to ) at 88.75 Hz of vibration. This novel approach of signal sensitivity enhancement is also validated with antibody immobilization-based Vi antigen detection for typhoid assessment. The sensitivity enhancement up to ∼15% is achieved for Vi antigen detection under the mechanical vibration of 120 Hz. The sensor is fabricated using microfabrication technology. The vibration-assisted ultrasensitive biosensing platform is also prototyped as a portable and Internet of Thing (IoT) enabled device, suitable for point-of-care applications. Detailed features of the prototype along with the test results are elaborated in the paper.

Evaluation of Road Service Performance Based on Human Perception of Vibration While Driving Vehicle

Road surface monitoring is a significant issue in providing smooth road infrastructure for vehicles, and the key to road condition monitoring is to detect road potholes that affect driving comfort and transportation safety. This paper presents a simple, efficient, and accurate way to evaluate road service performance based on the acquisition of road vibration data by vibration sensors installed in vehicles. Inspired by the discrete fast Fourier transform, the vibration acceleration is processed, and the RMS value of vibration acceleration at 1/2 octave is calculated, after which the road vibration level is calculated. The vibration level is optimized according to the human body’s sensitivity to different frequencies of vibration, resulting in road service performance indicators that can reflect the human body’s real feelings. According to the road service performance index values on the road grading, combined with GPS data on the electronic map color block labeling, the results obtained for the road condition warning, road maintenance, driver route selection have an important significance.

Non-contact low-frequency vibration rapid measurement based on hue-height mapping

A non-contact vibration measurement system based on camera-projector system and hue-height mapping is proposed. The CCD camera acquires the color deformed fringes with red (R) green (G) blue (B) channels, which is modulated by a vibrating loudspeaker, with the aim to demodulate the information of vibrations. In order to avoid the crosstalk between RGB channels, the sampling frames from RGB space are converted to hue (H) saturation (S) intensity (I) space. By using hue information, height value of each pixel point at different sampling frames can be restored, so as to obtain the vibration curve of the loudspeaker. The experiments compare the vibrations of different frequencies at several Hertz, and different amplitudes lower than millimeter degree. The results show that this optical image system can detect low-frequency vibrations with high accurate amplitudes, and meet the basic industrial measurement requirements.

Numerical Simulation of Temperature and Fluid Fields in Solidification Process of Ferritic Stainless Steel under Vibration Conditions

A three-dimensional model of a circular casting mold with a vibrating nucleus generator was established, and the characteristics of temperature and flow fields during the solidification process of ferritic stainless steel Cr17 in the casting mold were analyzed using finite element and finite difference methods. A standard k-ε turbulent current model was adopted to simulate the temperature field, and a standard k-ε model in Reynolds-averaged Navier–Stokes equations (RANS) was employed to deal with the flow field. The temperature field diffuses outward with a positive temperature gradient. Low degrees of undercooling can prevent solidified shells from forming rapidly on the surface of the nucleus generator. The temperature perpendicular to the direction of vibration is lower than that in the direction of vibration. The flow field exhibits a heart-shaped distribution and spreads gradually outward. The uniform distribution of grains can be achieved at three different frequencies of vibration. The results show that the degree of undercooling affects the distribution of the temperature field while the frequency of vibration affects the flow field significantly. Under the conditions of undercooling of 540 K and vibration frequency of 1000 Hz, the region perpendicular to the vibration direction of the nucleus generator is the optimum area for equiaxed crystal formation.

Development of Absorbed Blasting Vibration Energy Index for the Evaluation of Human Comfort in Multistorey Buildings

There have been civil disputes and complaints regarding the negative effects of blasting vibration on buildings around the blasting site. By considering the effect of blasting vibration on a human body as a process of energy transfer and conversion, the human body absorbed blasting vibration energy (ABVE) index has been developed for comfort evaluation. Using dynamic monitoring and theoretical analysis, the elevation amplification effect and selective amplification effect on different frequency components of the ABVE have been investigated. The elevation amplification factor and selective amplification coefficients on different frequency components of the ABVE index for a typical 4-storey brick and concrete building have been determined. Based on the results, the magnitude and frequency components of the ABVE index in different parts especially in different storeys for the typical building have been determined. According to the characteristics of human body’s response to vibrations of different frequencies, the frequency-based weighting method of ABVE index has been simplified. By calculating the combined effect of vibrations from all directions, the total human body ABVE and its frequency components at different floors of the building can be determined accurately. This can be used to evaluate the human body comfort against blasting vibration at different floors.

Good vibrations: Global processing can increase the pleasantness of touch.

Visual-tactile carry-over effects of global/local processing (attention to the whole, versus the details) have been reported under active touch conditions. We investigated whether carry-over effects of global/local processing also occur for passive touch and whether global/local processing has differential effects on affective and discriminative aspects of touch. Participants completed two tactile tasks involving pleasantness rating and discrimination of a set of tactile vibrations before and after completing a version of the Navon task that encouraged a focus on the global (n = 30), local (n = 30), or both (n = 30) features of a series of visual stimuli. In line with previous research suggesting a link between global processing and positive emotion, global processing increased pleasantness ratings of high-frequency (but not low-frequency) tactile vibrations. Local processing did not improve the ability to discriminate between vibrations of different frequencies, however. There was some evidence of a tactile-visual carry-over effect; prior local processing of tactile vibrations reduced global precedence during the Navon task in the control group. We have shown carry-over effects of global versus local processing on passive touch perception. These findings provide further evidence suggesting that a common perceptual mechanism determines processing level across modalities and show for the first time that prior global processing affects the pleasantness of touch.

Spectral analysis of absorption characteristics of particulate dampers to mitigate building vibration

Particulate medium can act as efficient damper for building internal and external vibrations. Mechanical properties of the particulate material, their shape and size distributions determine the vibration absorption characteristics of these dampers. It has been shown that an unconsolidated particulate damper act as a bandpass filter for vibration frequencies of mechanical vibrations transmitted through them. The particulate dampers can also have frequency bandgap structure, where transmitted mechanical vibration of a particular frequency is strongly attenuated by absorption and scattering. The samples of non-consolidated uniform fused-silica spherical particulates are subjected to mechanical vibrations of different frequencies and intensities to determine their absorption characteristics as a function of frequency, intensity, and direction of propagation. The effects of a particulate diameter and layer thickness on absorption characteristics are determined experimentally, at low and at high frequency ranges encountered in building vibration. The goal of this investigation is to find the required absorption characteristics for particulate damper for applications to mitigate building vibration.

Effects of laser interaction with living human tissues

With the help of a highly sensitive laser device with the wavelength λ = 0.808 pm, which is optimal for deep penetration of the radiation into biological tissues, the effects associated with the appearance of uncontrolled human infrasonic vibrations of different frequencies were investigated. It was established that the observed fluctuations are associated with the vascular system which is characterized by its own respiratory movements, occurring synchronously with the movements of the respiratory muscles, the operation of the heart muscle, and the effect of compression ischemia. The effect of “enlightenment” of a tissue is observed with stopping of blood flow in vessels by applying a tourniquet on the wrist.

Impact of the halogenated substituent on electronic and charge transport properties of organic semiconductors: A theoretical study

The electronic and charge transport properties of the derivatives based on tetracene with aryl and halogenated aryl substituents have been investigated theoretically. This kind of functionalization is demonstrated to have a significant effect to stabilize the molecular orbital, densify the molecular packing, enhance the electronic coupling, and further lead to a high mobility, though it would also cause some increases in the reorganization energy. The packing modes of FPPT and PPT crystals are analyzed in details and effective coupling projected areas are put forward to understand the intermolecular interactions. Interestingly, FPPT is found to have a well-ordered packing as well as the improved hole mobility of 4.67cm2V−1s−1. In addition, the contributions of different frequencies of vibration to the total reorganization energies are also discussed with the normal mode analysis. This study clarifies the halogenated substituent effect on transport properties and provides the guide for molecular design of novel functional materials.

Masking of thresholds for the perception of fore-and-aft vibration of seat backrests

The detection of a vibration may be reduced by the presence of another vibration: a phenomenon known as ‘masking’. This study investigated how the detection of one frequency of vibration is influenced by vibration at another frequency. With nine subjects, thresholds for detecting fore-and-aft backrest vibration were determined (for 4, 8, 16, and 31.5-Hz sinusoidal vibration) in the presence of a masker vibration (4-Hz random vibration, 1/3-octave bandwidth at six intensities). The masker vibration increased thresholds for perceiving vibration at each frequency by an amount that reduced with increasing difference between the frequency of the sinusoidal vibration and the frequency of the masker vibration. The 4-Hz random vibration almost completely masked 4-Hz sinusoidal vibration, partially masked 8- and 16-Hz vibration, and only slightly masked 31.5-Hz vibration. The findings might be explained by the involvement of different sensory systems and different body locations in the detection of different frequencies of vibration.