Vibration Patterns Research Articles

Differentiated tactile effects of vibration modal superposition considering the time course

Several theoretical studies on modal superposition methods to achieve tactile differentiation have been reported. However, there is still a lack of in-depth analysis and understanding of the regularity of the superposition of vibration modes and the resulting differences in tactile sensation. The touch beam vibrations are no longer in the form of standing waves after the modal superposition. The vibration points on the touch beam will present a periodic motion over time, instead of simply moving harmonically. The vibration response of the touch beam at high frequency, gave subjects a dramatically different tactile perception from that of a single inherent mode. Therefore, this paper reshapes the modal superposition theory of the haptic feedback technique to classify the vibration modes generated by the modal superposition of touch beams showing differences in tactile sensations considering the time course. The analysis and tactile texture prediction theories are improved compared to previous studies. The tactile sensation generated by the vibration patterns of left-right sway were found in the touch beam. Finally, the correctness of the tactile differentiation achieved by the modal superposition method was demonstrated by psychophysical assessment for different finger conditions.

Application of Generative Autoencoders in the Detection of Anomalies in Hypercompressors

Hypercompressors are essential assets that compress high-flow-rates of ethylene to pressures between 100~350 MPa in the LDPE industry. They are sources of essential risks and costs. This work proposes an unsupervised and univariate monitoring method for detecting anomalies in hypercompressors through data collected from an online monitoring system in an actual installation. A variational autoencoder learns the process of generating shapelets associated with vibrational patterns. A combination of matrix profile algorithms automatically selects the training data set. A β-VAE composed of MLP layers is trained and applied on the input space so that a voting operation and a box-cox transformation on the absolute residual errors between the inputs and outputs lead to the upper outlier detection threshold, obtained by the Tukey fence method. The model detected suspicious vibration patterns classified a priori as potential anomalies.

Methods of vibration field control using actuator array for improving the panel speaker sound

The panel speaker occupies a small volume, so it has significant merit potential in application to modern machines and devices in the age of Internet-of-Things. However, the severe fluctuation in the radiated sound spectrum due to the multi-modal vibration behaviour of finite panels has been an inherent problem. The application of damping can reduce the resonance effect, but the frequency range is limited to a narrow band. Actively, the actuator array can control the vibration field of the plate. The vibration rendering for the desired vibration pattern or the elimination of some modes is possible by controlling the modal contribution or the boundary impedance in the frequency range of interest. An inverse formulation, which is analogous to the acoustic field rendering problems, should be solved to determine the actuators' control gain for achieving the desired response. In this presentation, several methods for active array control of the vibration field for panel speakers are compared: vibration field rendering using the modal approach, direct inverse technique fulfilling the desired sound radiation, boundary impedance control using traveling wave, and sparse actuator array allocation method. Their merits and demerits are discussed regarding the future potential in various applications.

Effect of oxidation temperature on Raman spectra of graphite samples

The recent work investigates the relationship between the characteristics of the Raman spectra and the oxidation temperature of thermal-treated graphite samples in air at various temperatures ranging from 200°Cto 800 °C. Our findings indicate that thermal oxidation of graphite in air leads to the enhancement of the 2D vibration pattern while reducing the intensity of the D vibration pattern. Moreover, we report that chemical reduction begins at 550 °C. Furthermore, our results demonstrate that thermal oxidation causes a decrease in the disorder within the samples.

Enzyme-triggered approach to reduce water bodies' contamination using peroxidase-immobilized ZnO/SnO2/alginate nanocomposite

Enzyme immobilization on solid support offers advantages over free enzymes by overcoming characteristic limitations. To synthesize new stable and hyperactive nano-biocatalysts (co-precipitation method), ginger peroxidase (GP) was surface immobilized (adsorption) on ZnO/SnO2 and ZnO/SnO2/SA nanocomposite with immobilization efficacy of 94 % and 99 %, respectively. Thereafter, catalytic and biochemical characteristics of free and immobilized GP were investigated by deploying various techniques, i.e., FTIR, PXRD, SEM, and PL. Diffraction peaks emerged at 2θ values of 26°, 33°, 37°, 51°, 31°, 34°, 36°, 56°, indicating the formation of SnO2 and ZnO. The OH stretching of the H2O molecules was attributed to broad peaks between 3200 and 3500 cm−1, whereas ZnO/SnO2 spikes occurred in the 1626–1637 cm−1 range. SnO stretching mode and ZnO terminal vibrational patterns have been verified at corresponding wavelengths of 625 cm−1 and 560 cm−1. Enzyme entrapment onto substrate was verified via interactions between GP and ZnO/SnO2/SA as corroborated by signals beneath 1100 cm−1. GP-immobilized fractions were optimally active at pH 5, 50 °C, and retained maximum activity after storage of 4 weeks at −4 °C. Kinetic parameters were determined by using a Lineweaver-Burk plot and Vmax for free GP, ZnO/SnO2/GP and ZnO/SnO2/SA/GP with guaiacol as a substrate, were found to be 322.58, 49.01 and 11.45 (μM/min) respectively. A decrease in values of Vmax and KM indicates strong adsorption of peroxidase on support and maximum affinity between nano support and enzyme, respectively. For environmental remediation, free ginger peroxidase (GP), ZnO/SnO2/GP and ZnO/SnO2/SA/GP fractions effectively eradicated highly intricate dye. Multiple scavengers had a significant impact on the depletion of the dye. In conclusion, ZnO/SnO2 and ZnO/SnO2/SA nanostructures comprise an ecologically acceptable and intriguing carrier for enzyme immobilization.

Transverse vortex-induced vibration of two elliptic cylinders in tandem: Effects of spacing

Renewable energy converters, such as bio-inspired fluttering foils, are gaining popularity due to their eco-friendly properties. However, the system with multiple objects has received scant attention. Here, we analyze how spacing influences the transverse (one-degree-of-freedom) vortex-induced vibration of two tandem identical elliptic cylinders at a constant Reynolds number by employing a wide range of reduced velocities (Ur∈[2,14]) and space ratios (L∗∈[2,6]). The incompressible Navier–Stokes equations are solved using the overset mesh method in the OpenFOAM® library. The findings indicate that the wake structure goes through eight distinct wake modes, as well as two gap flow patterns (reattachment and co-shedding). Vibrational responses, force parameters, and flow patterns determine three spacing configurations. At a small spacing (L∗=2), the upstream cylinder (UC) has the traditional lock-in (the frequency ratio fy/fn≃0.95–1.05) at the reduced velocity (Ur≃7), and the downstream cylinder (DC) has a narrow lock-in region around Ur≃9. However, the UC has a wide soft-lock-in (the synchronization region of fy/fn≃1.15) at high reduced velocities (Ur≃8–10). Here, the transverse vibrations of both cylinders, but especially the DC, reach relatively high amplitudes. At a moderate spacing (L∗=3), the UC bears a lock-in zone analogous to a single cylinder with the same mass ratio, while the DC shows a vast soft-lock-in zone (Ur≃8–14). At a large spacing (L∗=4, 5, and 6), the amplitude of the DC is often larger than that of a single cylinder when it is in the lock-in region. The DC exhibits a peak in amplitude at Ur = 7 and a wake-galloping region for Ur > 12.

The effects of vocal tract constrictions on aerodynamic measures in a synthetic vocal fold model.

According to nonlinear source-filter theory, as the strength of the coupling between the source and filter increases, typically by a decrease in the vocal tract cross-sectional area, the resultant increase in the inertance of the vocal tract yields an increase in the interactions between acoustic pressures within the vocal tract and the changing glottal airflow and/or the vibratory pattern of the vocal folds as noted in Titze [(2008). J. Acoust. Soc. Am. 123(4), 1902-1915]. The purpose of the current research was to examine the effects of parametric vocal tract constrictions mimicking epilaryngeal tube and lip narrowing on aerodynamic measures in a dynamic self-oscillating physical model of the vocal folds and vocal tract. Multilayered silicone vocal fold models were created based on Murray and Thomson [(2011). J. Visualized Exp. 58, e3498] and Murray and Thomson [(2012). J. Acoust. Soc. Am. 132(5), 3428-3438] and mounted to a simple synthetic trachea and supraglottal vocal tract model. Four constriction cross-sectional areas were examined at two locations (i.e., at the epilarynx and lip regions). Phonation threshold pressure and flow were measured at phonation onset and offset using four M5-CONV vocal fold models. Results indicated that both constriction magnitude and location are relevant factors in determining glottal aerodynamics. In general, a narrow epilarynx tube or lip constriction resulted in the lowest onset pressures and airflows while the no vocal tract condition resulted in the highest onset pressures and airflows.

Effects of Cognitive Load on Vocal Fold Vibratory Patterns in Bilingual Speakers of Low and High German

Effects of Cognitive Load on Vocal Fold Vibratory Patterns in Bilingual Speakers of Low and High German

Influence of coal-measure kaolinite with different types on the preparation of kaolinite nanotube

Coal-measure kaolinite with different types were selected to explore the influence of raw mineral on the preparation of intercalation compounds and kaolinite nanotubes. Types of coal-measure kaolinite were feldspar-pseudomorph kaolinite (HSS), worm-like kaolinite (XY), brain striatum kaolinite (CBM), mica-pseudomorph kaolinite (CBM) and crypto crystalline kaolinite (HW and HY), respectively. And the average crystal size of coal-measure kaolinite after grinding of HSS, XY, CBM, HW and HY were 2.60 μm, 6.81 μm, 3.28 μm, 0.52 μm and 0.32 μm, respectively. Characterization methods of XRD, FTIR and SEM were utilized to reveal the change in the crystal structure of kaolinite before and after intercalation reactions, the vibrational pattern of the chemical bond and the surface morphology characteristics of raw minerals and kaolinite nanotubes. Results showed that intercalation effects were significantly different among the selected coal-measure kaolinite, and the intercalation rates of intercalation compound of HSS-KD, XY-KD, CBM-KD, HW-KD and HY-KD were 80.71%, 83.33%, 82.99%, 55.13% and 65.23%, respectively. That is to say, Intercalation rates of feldspar-pseudomorph kaolinite, worm-like kaolinite, brain striatum kaolinite and mica-pseudomorph kaolinite were significantly higher than those of crypto crystalline coal-measure kaolinite which were reflected from intercalation compound of coal-measure kaolinite/dimethyl sulfoxide. Furthermore, the intercalation rates of the precursor intercalation compounds affect the intercalation effect of macromolecular intercalation agents and the yield of kaolinite nanotubes. According to the SEM patterns of kaolinite nanotubes, yield of kaolinite nanotube of HSS, XY, CBM, HW and HY were 80%, 88%, 72%, 28% and 35%, respectively. It could be concluded that yield of kaolinite nanotube of coarse crystalline coal-measure kaolinite was higher than that of crypto crystalline coal-measure kaolinite.

The Numerical Study for the Effect of Stiffness Matching on Wheel–Rail Curve Squeal Noise

This study delves into the phenomenon of high-frequency squeal noise occurring as trains traverse small-radius curved tracks and investigates the factors influencing wheel–rail curve squeal noise, particularly focusing on stiffness matching. To achieve this, we initially construct a finite element model of the wheel–rail friction system using finite element software ABAQUS 2022, validating its accuracy against Coulomb’s friction law. Subsequently, we employ complex eigenvalue analysis to extract the complex eigenvalues and vibration modes of the wheel–rail system, enabling us to study the positions and vibrational patterns associated with squeal noise by analyzing the amplitudes of unstable modes. Finally, we assess the impact of wheel–rail stiffness matching on curve squeal noise, using wheel–rail material stiffness and rail support stiffness as key variables. The outcomes of this study reveal the following insights: (1) Unstable modes closely align with the resonant frequency and mode shape of the wheel and rail. (2) Curve squeal noise primarily emanates from vibrations at the rim, railhead, and rail foot. (3) Wheel and rail stiffness significantly affect squeal noise, with a significant deviation in the elastic modulus between rail and wheel increasing the likelihood of squeal noise, while an optimal ratio of about 1.2 is observed. (4) Rail support stiffness plays a discernible role in controlling curve squeal noise. Theoretically, maintaining an appropriate support stiffness level can minimize the negative damping ratio of unstable modes, providing a viable avenue for curve squeal noise control.

Mechanical vibration patterns elicit behavioral transitions and habituation in crawling Drosophila larvae.

How animals respond to repeatedly applied stimuli, and how animals respond to mechanical stimuli in particular, are important questions in behavioral neuroscience. We study adaptation to repeated mechanical agitation using the Drosophila larva. Vertical vibration stimuli elicit a discrete set of responses in crawling larvae: continuation, pause, turn, and reversal. Through high-throughput larva tracking, we characterize how the likelihood of each response depends on vibration intensity and on the timing of repeated vibration pulses. By examining transitions between behavioral states at the population and individual levels, we investigate how the animals habituate to the stimulus patterns. We identify time constants associated with desensitization to prolonged vibration, with re-sensitization during removal of a stimulus, and additional layers of habituation that operate in the overall response. Known memory-deficient mutants exhibit distinct behavior profiles and habituation time constants. An analogous simple electrical circuit suggests possible neural and molecular processes behind adaptive behavior.

A Somatosensory Computation That Unifies Limbs and Tools.

It is often claimed that tools are embodied by their user, but whether the brain actually repurposes its body-based computations to perform similar tasks with tools is not known. A fundamental computation for localizing touch on the body is trilateration. Here, the location of touch on a limb is computed by integrating estimates of the distance between sensory input and its boundaries (e.g., elbow and wrist of the forearm). As evidence of this computational mechanism, tactile localization on a limb is most precise near its boundaries and lowest in the middle. Here, we show that the brain repurposes trilateration to localize touch on a tool, despite large differences in initial sensory input compared with touch on the body. In a large sample of participants, we found that localizing touch on a tool produced the signature of trilateration, with highest precision close to the base and tip of the tool. A computational model of trilateration provided a good fit to the observed localization behavior. To further demonstrate the computational plausibility of repurposing trilateration, we implemented it in a three-layer neural network that was based on principles of probabilistic population coding. This network determined hit location in tool-centered coordinates by using a tool's unique pattern of vibrations when contacting an object. Simulations demonstrated the expected signature of trilateration, in line with the behavioral patterns. Our results have important implications for how trilateration may be implemented by somatosensory neural populations. We conclude that trilateration is likely a fundamental spatial computation that unifies limbs and tools.

Intelligent Vibration Monitoring System for Smart Industry Utilizing Optical Fiber Sensor Combined with Machine Learning

In this paper, we proposed and experimentally demonstrated the association of a fiber Bragg Grating (FBG) sensing system with You Only Look Once V7 (YOLO V7) to identify the vibration signal of a faulty machine. In the experiment, the YOLO V7 network architecture consists of a backbone, three detection heads (Headx3), a path aggregation network (PAN), and a feature pyramid network (FPN). The proposed architecture has an FBG sensor and the FBG interrogator employed for collecting sensing vibration signals or vibration data when degradation or fault occurs. An FBG interrogator collects vibration data independently, and then the YOLO V7 object detection algorithm is the recognition architecture of the vibration pattern of the signal. Thus, the proposed vibration recognition or detection is an assurance for detecting vibration signals that can support monitoring the machine’s health. Moreover, this research is promising for ensuring a high accuracy detection of faulty signals rate in industrial equipment monitoring and offers a robust system, resulting in remarkable accuracy with an overall model accuracy of 99.7%. The result shows that the model can identify the faulty signal more accurately and effectively detect the faulty vibration signal using the detection algorithm.

Vocal Fold Vibration of the Whistle Register Observed by High-Speed Digital Imaging

Singers use a whistle register to sing at a fundamental frequency above 1000Hz. In previous studies, vocal fold vibrations with or without complete closure and partial vocal fold vibrations were observed depending on the subject. However, the production mechanism of the whistle register is not yet clearly understood because of the limitations of the imaging device for the glottis and subjects. This study aims to examine vocal fold vibrations in a whistle register. The dynamic behavior of the glottis was recorded for six singers (four females and two males) using a high-speed digital imaging device with a frame rate above 10,000fps. Audio signals were recorded simultaneously. The data were analyzed in the form of topography, glottal area waveforms, spectrograms, and phonovibrography to examine spatiotemporal patterns of glottal motion. The vibratory motion of the vocal folds was classified into six patterns. The first pattern was the entire vocal fold vibration with complete closure during the closed phase. The second to fifth was the entire vocal fold vibration without complete closure, where a gap was observed for the full length of the vocal folds for the second, at the posterior part of the glottis for the third, at the anterior for the fourth, and at both ends for the fifth. In the sixth pattern, the vocal folds vibrated partially. Our results support the previous findings on the vibration of the vocal folds. In addition, we identified novel vibratory patterns in the vocal folds. We conclude that the production of the whistle register is not just an extension of the falsetto register to the higher fundamental-frequency region; rather, the production mechanism of the whistle register appeared to be diverse as a means of vocalization.

Finite element-based diffraction correction for piezoelectric transducers accounting for diffraction at transmission, propagation, and reception.

Existing diffraction correction models for ultrasonic transmit-receive measurement systems rely on simplifying assumptions with respect to the boundary conditions at the transmitter or receiver. Common simplifications include approximating the sound field radiated by a piezoelectric transducer using a baffled piston model and assuming that the receiver's electrical response is proportional to the spatially averaged free-field pressure over its front surface. In many applications, such simplifications may be adequate, but their validity and accuracy need to be evaluated and quantified. Here, a diffraction correction model utilizing the full set of electrical and mechanical boundary conditions at the transmitter and receiver is presented, avoiding these simplifications. The model is based on finite element modeling of coaxially aligned piezoelectric transducers in a fluid medium. Comparison is made with existing models for an example case of cylindrical piezoelectric ceramic disk transducers operating in air at 50-300 kHz and 0.03-2 m apart, relevant for, e.g., sound velocity and absorption measurements in fluids and ultrasonic gas flow metering. In the near-field, errors introduced by the simplifications are up to 3 dB and 47° for the first radial resonance. Generally, such errors are application-specific and depend on distance, frequency, transducer construction, vibration pattern, and medium properties.

Objective tools in pediatric voice therapy: A path to improved outcomes

This is an invited presentation in the Special Session titled, “Voice therapy: objective measurement science and clinical efficacy.” Pediatric dysphonia (hoarseness) is a common condition with prevalence estimates ranging from 1.4% to 23.9%. Dysphonia can be detrimental to children both psychologically and academically; hence, early identification and restoration of optimal vocal health is critical. Direct visualization of vocal fold vibratory patterns is fundamental for appropriate diagnosis and treatment of vocal fold pathology. Thus, evaluation of vocal fold structure and cycle-to-cycle vibratory motion through techniques of direct visualization of the vocal fold is essential for clinical assessment and measurement of treatment outcomes. This session will discuss the most recent advances in objective voice assessment and measurement of voice therapy outcomes in children. The focus will be on discussing an innovative approach that leverages high-speed videoendoscopy and a cutting-edge custom developed laser projection system for quantitative evaluation of lesion size and comprehensive evaluation of opening and closing phase dynamics of the glottal cycle before and after voice therapy in children with vocal fold nodules.

Voice quality and its effects on university students' listening effort in a virtual seminar room

A teacher’s poor voice quality may increase listening effort in pupils, but it is unclear whether this effect persists in adult listeners. Thus, the goal of this study is to examine the impact of vocal hoarseness on university students' listening effort in a virtual seminar room. An audio-visual immersive virtual reality environment is utilized to simulate a typical seminar room with common background sounds and fellow students represented as wooden mannequins. Participants wear a head-mounted display and are equipped with two controllers to engage in a dual-task paradigm. The primary task is to listen to a virtual professor reading short texts and retain relevant content information to be recalled later. The texts are presented either in a normal or an imitated hoarse voice. In parallel, participants perform a secondary task which is responding to tactile vibration patterns via the controllers. It is hypothesized that listening to the hoarse voice induces listening effort, resulting in more cognitive resources needed for primary task performance while secondary task performance is hindered. Results are presented and discussed in light of students’ cognitive performance and listening challenges in higher education learning environments.

Investigating the Haptic Perception of Directional Information Within a Handle.

This paper studies the perception of 2-dimensional directional cues presented on a hand-held tangible interface that resembles a cylindrical handle. The tangible interface is designed to be comfortably held with one hand and houses five custom electromagnetic actuators composed of coils as stators and magnets as movers. We carried out a human subjects experiment enrolling 24 participants, analysing the recognition rate of directional cues using the actuators either to vibrate or tap in sequence across the user's palm. Results show an impact of the positioning/holding of the handle, the mode of stimulation, and the directional indication sent via the handle. There was also a correlation between the score and the confidence of the participants, showing that participants are more confident when recognising vibration patterns. Overall, results supported the potential of the haptic handle to provide accurate guidance, with recognition rates higher than 70 % in all conditions and higher than 75 % in the precane and power wheelchair configurations.

Methodology for the Acoustic Analysis of Acoustic Guitar Top Plates Designs by Additive Manufacturing

Nowadays, tools such as Additive Manufacturing (AM) contribute directly to an increase in the value of Industrial Design through the development of new products focused on customization. Specifically, the acoustic guitar is a good example of this, because it is a complex product to study due to the great variety of possible designs depending on the materials and the way they are obtained, which has repercussions on the final sound of the instrument. Due to the above, this paper develops a methodology for the study of the acoustic response depending on the design of an acoustic guitar using AM with Polylactic Acid (PLA) material. The methodology is divided into two types of tests: an acoustic test to capture the frequencies emitted by transmitting a sweep of frequencies across the audible spectrum to the soundboard, and another to visualize the vibrational patterns at five specific harmonic frequencies of the guitar by analyzing the movement of the soundboard and the influence of the bracing. This second test includes the PLA designed top with a reinforcement structure in its soundboard and a case in order to compare this design with a wooden guitar of the same size whose top has no reinforcement at all. From the tests carried out, it can be seen that the acoustics recorded by a top made of PLA can provide a good acoustic response compared to a wooden guitar, giving the possibility to create customized guitars according to the musician's tastes.

VibWall : Smartphone’s Vibration Challenge-response for Wall Crack Detection

As the building ages, the wall structure may become deteriorated (e.g., wall cracks, discontinuities, and corrosion) due to the variation of the environment (i.e., temperature and humidity). Moreover, these wall cracks, discontinuities, and corrosion will affect the living comfort and coziness. As such, the wall health diagnostic becomes crucial for the safety and comfort of modern buildings. However, the existing wall health detection techniques (e.g., UWB radars, acoustic sensing, and sensor embedding techniques) are high-cost, not ubiquitous, and not robust to the variation of the environment. In this article, we propose VibWall , a system that can use the smartphone’s sensors (i.e., accelerometer, gyroscope, and vibrator) to detect the wall’s structural health. Specifically, the wall cracks can be detected for living safety, comfort, and coziness. Our key idea is that the smartphone’s vibration is absorbed, reflected, and propagated disparately based on the physical structure of the wall. To be specific, we employ a novel challenge-response scheme, where the challenge is a sequence of heterogeneous vibration patterns from the smartphone’s vibrator, and the responses to these vibrations are sensed by the smartphone’s gyroscope and accelerometer sensors. Then, the machine learning-based classifier (e.g., random forest classifier) will be used to discriminate between the healthy wall and the wall with cracks, discontinuities, or corrosion based on these responses. Our experimental results show good performance on the wall’s structural health detection with the wall specimen and real-world walls.