Vibration Pulses Research Articles

Sex and caste effects on the vibrational sensitivity in honey bees (Apis mellifera)

In the darkness of their nests, most social insect species communicate relying on chemical, tactile, electrical and mechanical signals. In honeybees, vibrational signals play a role not only in worker communication but also in communication among virgin queens in the process of swarming. Whereas the sensitivity to vibrations has been well studied in worker bees, vibrational sensitivity of queens and drones has never been investigated. We therefore studied the sensitivity to vibrations comparatively in workers, virgin and laying queens and in drones, focusing on the frequency range mainly used by virgin queens (350–500 Hz). Bees were tested behaviorally for responses to pulses of substrate borne vibrations in arenas placed on vibrational exciters. Vibrational amplitudes were measured using (LDV-calibrated) accelerometers. Real stimuli and sham stimuli were presented in a pseudorandom order. The threshold was defined as the lowest tested amplitude at which significantly more behavioral reactions were shown to real stimuli than to sham stimuli. Workers and virgin queens respond to amplitudes down to 0.25 m/s2. The thresholds of laying queens are substantially higher and they respond to minimum amplitudes of 0.55 m/s2. Drones show responses to amplitudes down to 0.6 m/s2. We conclude that sex and caste have effects on vibrational sensitivity in honeybees: virgin queens are significantly more sensitive than laying queens, indicating that a high sensitivity is crucial for survival during the process of swarming; workers are likewise highly sensitive to execute efficient everyday work; drones are significantly the least sensitive.

Quantitative assessments of honeybee colony’s response to an artificial vibrational pulse resulting in non-invasive measurements of colony’s overall mobility and restfulness

In this work we aim to provide a quantitative method allowing the probing of the physiological status of honeybee colonies by providing them with a gentle, short, external artificial vibrational shockwave, and recording their response. The knock is provided by an external electromagnetic shaker attached to the outer wall of a hive, driven by a computer with a 0.1 s long, monochromatic vibration at 340Hz set to an amplitude that occasionally yields a mild response from the bees, recorded by an accelerometer placed in the middle of the central frame of the colony. To avoid habituation, the stimulus is supplied at randomised times, approximately every hour. The method is pioneered with a pilot study on a single colony hosted indoors, then extended onto eight outdoors colonies. The results show that we can quantitatively sense the colony’s overall mobility, independently from another physiological aspect, which is phenomenologically explored. Using this, a colony that is queenless is easily discriminated from the others.

The role of intraspecific variation in bumblebee body size and behavior on buzz pollination of a tropical legume species.

The outcomes of generalized mutualisms rely on partner trait variation. In pollination mutualisms, although less explored, intraspecific variation in pollinator traits can be pivotal for successful pollination. We investigated the role of intraspecific body size and behavioral trait variations of bumblebee Bombus morio on the pollination of a buzz-pollinated legume species, Chamaecrista latistipula. To explore the impact of body size and behavior of B. morio on the pollination of C. latistipula, we observed visits to virgin flowers and quantified the pollen removal and deposition (pollination performance) and fruit and seed production (reproductive fitness). By analyzing video and sound recordings, we measured B. morio body size and behavior on each flower, including bee vibration descriptors. We observed intraspecific behavioral differences among B. morio bumblebees associated with different body sizes. Larger bumblebees had half the handling time and vibrational pulses, less angular displacement within flowers, and larger relative peak amplitudes during vibrations than smaller bumblebees did. Regardless of their large variation in size and behavior, bumblebees were equally effective in removing pollen and pollinating flowers. The high female reproductive fitness was independent of bumblebee body size and behavior, likely due to the interaction between both. On the other hand, larger bumblebees visited flowers for shorter periods, probably promoting higher male reproductive fitness. This study is the first to highlight the large intraspecific variation of bumblebee body size and behavior in buzz-pollinated flowers in the field. Together, body size and behavior effects unexpectedly cancel each other, generating a high buzz pollination efficiency.

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 Novel Time–Frequency Feature Fusion Approach for Robust Fault Detection in a Marine Main Engine

Ensuring operational reliability in machinery requires accurate fault detection. While time-domain vibration pulsation signals are intuitive for pattern recognition and feature extraction, downsampling can reduce analytical complexity, but may result in low-precision data, affecting fault detection performance. To address this, we propose time–frequency feature fusion, combining information from both the time and frequency domains for fault detection. Our approach transforms vibrational pulse data into instantaneous revolutions per minute (RPM) and employs statistical analysis for the time-domain features. For the frequency-domain features, we use the combined method of empirical mode decomposition and independent component analysis (EMD-ICA), along with the Wigner bispectrum method to capture the nonlinear characteristics and phase conjugation. Using a deep neural network (DNN), we classify the anomaly states, demonstrating the effectiveness and versatility of our approach in detecting anomalies and improving diagnostic precision. Compared to using time or frequency features alone, our time–frequency feature fusion model achieves higher accuracy, with 100% accuracy at lower downsampling rates and 96.3% accuracy at a downsampling rate of 100×.

Experimental investigation of a solar evacuated tube collector embedded with a heat pipe using different nanofluids and controlled mechanical exciting pulsations

Numerous studies have been conducted to enhance the thermal performance of evacuated tube solar thermal collectors using various techniques, such as different working fluids, concentrators, and modifications to the absorber design. This work presents a parametric study to improve the thermal performance of a solar-evacuated tube collector embedded with a heat pipe (SETCHP) by utilizing different types of nanofluids and controlled mechanical excitation. The experiment involved six identical SETCHPs operating under the same conditions, with one setup filled with pure acetone as a reference. The second and third setups were filled with (0.5% vol Al2O3)/based acetone and (0.5% vol CuO)/based acetone, respectively. The remaining three setups were modified by imposing controlled mechanical excitation with different frequencies (27–82 Hz) to investigate the effect of vibration on thermal performance. The results demonstrated that the optimal enhancement was achieved with mechanical vibration pulses at 82 Hz, improving efficiency by 91% and 86% with Al2O3/based acetone and CuO/based acetone, respectively. The enhancement percentage of effective heat transfer coefficient (EHTC) and convective heat transfer coefficient (CHTC) varied with solar intensity and vibration, with improvements ranging from 5 to 82% and 3–53%, 26–160% and 5–60%, and 6.5–140% and 6.5–54% for pure acetone, Al2O3, and CuO (0.5% vol) acetone-based nanofluids, respectively.

SkinSense: Efficient vibration-based communications over human body using motion sensors

Recent growth in popularity of mobile and wearable devices has re-ignited the need for reliable and stealthy communication side-channels to enable applications such as secret/PIN sharing, co-location proofs and user authentication. Existing short-range wireless radio technology such as Bluetooth/BLE and NFC, although mature and robust, is prone to eavesdropping, jamming and/or interference, and is not very useful as a covert communication side-channel. This paper designs and implements SkinSense, a vibration-based communication protocol which uses human body/skin as a communication medium to create a low-bandwidth and covert communication channel between user-held mobile and wearable devices. SkinSense employs a novel frequency modulation technique for encoding bits as vibration pulses and a spectrogram-based approach to decode the sensed motion data (corresponding to the encoded vibration pulses) to reconstruct the transmitted bits. SkinSense is comprehensively evaluated for a variety of operational parameters, hardware setups and communication settings by means of data collected from human subject participants. Results from these empirical evaluations demonstrate that SkinSense is able to achieve a stable bandwidth of up to 6.6 bps, with bit error rates below 0.1 in our custom hardware setup, and can be employed as a practical communication side-channel.

Gear Crack Detection Based on Vibration Analysis Techniques and Statistical Process Control Charts (SPCC)

Vibration condition monitoring is a non-devastating technique that can be performed to detect tooth cracks propagating in gear systems. This paper proposes to apply a new methodology using time-domain analysis, frequency-domain analysis, and statistical process control charts (SPCC) for gear crack detection of a 10 DOF dynamic model of spiral bevel gear system (SBGS). The gear mesh stiffness effect used in the model has been studied analytically for different levels of crack faults. Adding Gaussian white noise is discussed as the first step to simulating the initial modeling signals of real-world conditions. Second, time-domain signal analysis was performed to identify periodic vibration pulses as failure components and calculate the statistical standard deviation (STD) feature as a fault-sensitive feature. Third, a fast Fourier transform (FFT) to time signals of the variable gear mesh stiffness was applied to determine the gear mesh frequency and sidebands to detect tooth cracks. Fourth, the SPCC was designed using the Shewhart X-bar chart and an exponentially weighted moving average (EWMA) chart based on the STD feature of the healthy gears. Finally, in the testing stage, the control charts are carried out with simulation signals under faulty conditions to detect the different levels of cracks. The results showed that the EWMA chart outperformed the time domain analysis, frequency domain analysis, and Shewhart X-bar chart in detecting all levels of cracks at an early stage.

Shaking Table Seismic Experimental Investigation of Lightweight Rigid Bodies

This study presents the findings of an extensive shaking table experimental campaign conducted on nine free-standing wooden specimens, aiming at providing insights on the rigid body motion of free-standing objects. The specimens, which differ in slenderness and size, are characterized by impairments in their base surface and most likely in their shapes, which also lead to asymmetric responses. The imperfections of the tested objects are an additional source of uncertainty with respect to the intrinsic chaotic character of the rigid body motion, which is a crucial factor that prevents the reproducibility of the tests and induces discrepancies between specimen responses and those of their ideal models. A contactless measurement strategy is employed to assure unaltered data acquisition. The experimental campaign includes free vibration tests, pulse excitation, and natural ground motions tests; the dynamic responses of the specimens are organized and rearranged, aiming at providing a comprehensive set of data that could be employed for calibrating numerical models accounting for imperfect conditions. The damping properties of the specimens are discussed, providing a novel estimation of the coefficient of restitution based on the free vibration tests. The limits of the ideal simple rigid model are highlighted, and the roles of size factor and aspect ratio are discussed according to the obtained results.

Substrate-borne vibrational signals and stridulatory organs for sexual communication in leafminer, Liriomyza sativae (Diptera: Agromyzidae).

The vegetable leafminer (Liriomyza sativae [Burgess]) is a highly polyphagous pest that threatens vegetables and horticultural plants. Although sexual communication is a key component of the animal behavioral repertoire, the mechanism underlying sexual communication in L. sativae remains to be elucidated. Here, we used laser vibrometry to characterize the vibrational signals emitted by L. sativae during pair formation. By emitting trains of vibrational pulses (male calling) the male initiated communication on the host plant. The female then became immobile and responded to the male calling by emitting replies (female replies), which in turn triggered male replies consisting of a rapid series of chirps and trills. If the female replied, a continuous exchange of male and female replies ensued, representing a duet. In playback trials, a playback signal caused responses from the opposite sex. Moreover, scanning electron microscopy revealed vibration-producing stridulatory organs in both male and female individuals. The files in males were more developed than those in females, and older male specimens had more signs of abrasion. The results provide new insight into the mating biology of L. sativae.

Frog embryos use multiple levels of temporal pattern in risk assessment for vibration-cued escape hatching

Stereotyped signals can be a fast, effective means of communicating danger, but animals assessing predation risk must often use more variable incidental cues. Red eyed-treefrog, Agalychnis callidryas, embryos hatch prematurely to escape from egg predators, cued by vibrations in attacks, but benign rain generates vibrations with overlapping properties. Facing high false-alarm costs, embryos use multiple vibration properties to inform hatching, including temporal pattern elements such as pulse durations and inter-pulse intervals. However, measures of snake and rain vibration as simple pulse-interval patterns are a poor match to embryo behavior. We used vibration playbacks to assess if embryos use a second level of temporal pattern, long gaps within a rhythmic pattern, as indicators of risks. Long vibration-free periods are common during snake attacks but absent from hard rain. Long gaps after a few initial vibrations increase the hatching response to a subsequent vibration series. Moreover, vibration patterns as short as three pulses, separated by long periods of silence, can induce as much hatching as rhythmic pulse series with five times more vibration. Embryos can retain information that increases hatching over at least 45s of silence. This work highlights that embryo behavior is contextually modulated in complex ways. Identical vibration pulses, pulse groups, and periods of silence can be treated as risk cues in some contexts and not in others. Embryos employ a multi-faceted decision-making process to effectively distinguish between risk cues and benign stimuli.

Razvoj metodoloških tehnika i algoritma za dijagnostikovanje savremenih usisnih sistema za motore sa unutrašnjim sagorevanjem

Type Diagnosing and detecting malfunctions in internal combustion engines (ICE) is not an easy task due to their complex design. Timely and high-quality ICE monitoring allows performance to be maintained and prevents breakdowns. Vibration and acoustic analysis is a powerful and informative tool for detecting faults even at an early stage. This article considers a method for determining the main malfunctions of the valvetrain (VT) (tightness of the "valve-seat" interface, thermal gap in the valve drive, valve opening and closing phases) by measuring and analyzing vibroacoustic pulses caused by the operation of individual engine elements. The maximum amplitude and the moment of vibration impulses are used as signal parameters. For the reference signal of the piston, the top dead center (TDC) of the cylinder under study, a vibration pulse from the impact of the piston on an elastic tip placed in the combustion chamber is taken. This technique makes it possible to exclude the external influences and inaccuracies associated with a change in the geometry ICE elements.

Диагностирование газораспределительного механизма на основе контроля виброколебаний его элементов

The operability and efficiency of the engines significantly depend on the periodic diagnostics of their technical condition. Currently, vibration-based damage detection (measurement of vibration characteristics of structures and mechanisms) is a promising area of research activity. The features of monitoring and diagnostics of internal combustion engines using vibroacoustic analysis are considered. In the article a method has been developed for determining the main malfunctions of the gas distribution mechanism (tightness of the valve-seat coupling, thermal gap in the valve actuator, valve opening and closing phases), consisting in measuring and analyzing vibroacoustic pulses caused by the operation of individual engine elements. The maximum amplitude (peak) and the moment of occurrence of vibration pulses are used as signal parameters. A vibration pulse from the impact of the piston on the elastic tip placed in the combustion chamber is taken as the reference signal of the TDC of the piston of the cylinder under study. The speed of rotation of the crankshaft up to 600 min-1 (does not exceed the frequency of scrolling by the starter) does not lead to the appearance of dangerous stresses in any of the elements of the engine and the device. At the same time, the tip made of Bflex plastic, as the most malleable element, can be repeatedly used. To ensure a trouble-free diagnostic process, calculations were carried out using the software – Solid Works Simulation and the finite element method (FEM) built into it. To calculate the stresses, the solver finds the displacements at each node, and then calculates the deformations and the final stress. As a result of the study, the proposed diagnostic method allows to achieve an accuracy of up to 96 %

Vibration-Based Pattern Password Approach for Visually Impaired People

The pattern password method is amongst the most attractive authentication methods and involves drawing a pattern; this is seen as easier than typing a password. However, since people with visual impairments have been increasing their usage of smart devices, this method is inaccessible for them as it requires them to select points on the touch screen. Therefore, this paper exploits the haptic technology by introducing a vibration-based pattern password approach in which the vibration feedback plays an important role. This approach allows visually impaired people to use a pattern password through two developed vibration feedback: pulses, which are counted by the user, and duration, which has to be estimated by the user. In order to make the proposed approach capable to prevent shoulder-surfing attacks, a camouflage pattern approach is applied. An experimental study is conducted to evaluate the proposed approach, the results of which show that the vibration pulses feedback is usable and resistant to shoulder-surfing attacks.

Use of the toolholder with the oriented stiffness for ultrasonic turning

An effective way of processing difficult-to-machine materials is ultrasonic cutting, which is carried out by applying ultrasonic vibrations to the movement of the cutter and contributes to a significant reduction in cutting force and increase processing productivity. The article presents the results of research on the efficiency of using a new device for ultrasonic cutting with an electrostrictive vibrating drive. The source of ultrasonic vibrations is an electrostrictive vibratory drive, which provides oscillations in the range of 10 - 20 kHz with amplitude of 10 - 15 microns. Experimental studies have confirmed the effectiveness of the proposed design of the toolholder to transmit the wave of ultrasonic vibrations almost perpendicular to the axis of the vibratory drive, which allows you to unload the vibrating drive from the cutting force and use vibration pulses only to deform elastic elements by the amplitude of ultrasonic vibrations. The device provides conditions for processing of difficult-to-process materials, allows increasing accuracy of processing of details, to reduce roughness of the processed surfaces and to increase productivity of processing.

Determination of the stages of the injection process for Common Rail injectors using vibration pulses

The study and modeling of the combustion process of diesel engines require knowledge of the injection characteristics. The information on the exact start, duration and end of the injection is required. For Common Rail injectors with electromagnetic control, the beginning and duration of the electronic control pulse are precisely known. The actual start and duration of the injection are not the same as those of the impulse and they are related to the movement of the nozzle needle. The experimental determination of the movement of the nozzle needle requires specially prepared experimental installations and expensive measuring instruments. In addition, the experimental injector must be prepared with design modifications allowing the incorporation of sensors. The article presents a method for determining the start and duration of injection of Common Rail injectors using the registration and analysis of vibration pulses generated in the injector body. The method is based on the fact that the nozzle needle causes vibrations in the injector body when lifting and seating.

Condition-dependent differences in male vibratory pre-copulatory and copulatory courtship in a nuptial gift-giving spider

Condition-dependent secondary sexual traits and signals are often crucial for mate choice decisions. Nuptial gifts, provided by the male to the female during mating, may represent an indicator of male condition, especially if production of the gift is energetically costly. Additionally, other signalling modalities may well play a role in mate choice in such systems. Females of the nursery web spider Pisaura mirabilis preferably mate with males that provide a prey item wrapped in silk. Apart from the nuptial gift, vibrational signals employed during courtship and mating may reveal additional information about male condition. We tested condition-dependence of male vibrational signals of well-fed versus starved males, when in contact with female dragline silk and during mating trials. Our results show that vibrational signals are produced in P. mirabilis, both during pre-copulatory courtship and during copulation. Male courtship signals were condition-dependent: males in good condition initiated signalling earlier and emitted more vibrational pulses than poor-condition males. They were also more likely to be accepted by the female for copulation. We additionally identified vibrational signals during copulation. These signals were different from pre-copulatory courtship vibrations but did not differ between the treatment groups. This study shows that vibrational communication plays an important role before and during copulation in P. mirabilis. It sets the stage for further experiments on spider biotremology associated with nuptial gift giving behaviour.Significance statementMale courtship behaviour can indicate a male’s condition and quality and be subject to female mate choice. Vibrational communication during mating plays a crucial role in many animal species. Spiders are known to be extremely sensitive towards vibrations, and there is evidence that vibratory signals are also used during courtship. Here, we study the nuptial gift-giving spider Pisaura mirabilis in which courtship entails providing a nuptial gift by the male to the female. The gift quality determines on the probability and duration of mating. We investigated the role of vibrational behaviour in this species by standardizing nuptial gifts. Our study demonstrates that vibratory signals comprise information about the male’s condition, that signals are also produced during mating and that courtship and copulatory signals are strikingly different. We suggest that vibrational communication provides important condition-dependent traits for female mate choice in addition to the nuptial gift.

Highly sensitive and flexible pressure sensor based on two-dimensional MoSe2 nanosheets for online wrist pulse monitoring

The advancement of portable and flexible electronics that is integrated with multiple sensing functions has increasingly drawn considerable interest. The fabricated sensors would have the ability to sense multiple deformations like pressing, twisting and trivial vibrations such as pulses of wrist vibrations to mimic human skin. Presently, we implemented an easy, cost-effective and optimized fabrication technique for production of pressure sensors based on MoSe2 nanosheets coated on cellulose paper. The present sensor exhibits an incorporation of large pressure sensitivity of 18.42 kPa−1 in pressure range 0.001–0.5 kPa, 7.28 kPa−1 in pressure range 1–35 kPa and 2.63 kPa−1 in pressure range 40–100 kPa, working in broad pressure range (from 0.001 to 100 kPa) and long-term stability up to 200 deformation cycles at 2 kPa. The sensor showed excellent response towards the detection of vibrations of machines including cellular phone, compressor, etc. Besides, the sensor shows excellent environmental stability and exhibits immune piezo-resistive response to temperature variation.

A 580 nW Dual-Input Energy Harvester IC Using Multi-Task MPPT and a Current Boost Converter for Heterogeneous Source Combining

Herein, we present a multi-energy harvesting interface integrated circuit (IC) that enables the efficient combination of heterogeneous power sources. An electromagnetic vibration energy generator (EVG) and a thermoelectric energy generator (TEG) are the two energy sources, which have quite different internal resistance (tens and kilo-Ohms). To solve the challenge of combining heterogeneous sources, we propose a current boost converter (CBC), which achieves the resistance transformation as well as the source type conversion. The challenge of realizing maximum power point tracking (MPPT) for each source is tackled by using a multi-task MPPT controller, which is efficiently shared between the two sources. To achieve energy harvesting under uncertain and random source conditions, we propose an input ( $V_{\text {IN}}$ )-dependent clock generator (VCG) and a vibration pulse detector (VPD). The VCG tracks the change of source conditions to generate the clock for the MPPT controller. The VPD allows tracking of the random amplitude and frequency changes of the EVG. The energy harvester is fabricated in a 0.18 $\mu \text{m}$ process with a thick top-metal option. Measured results show successful source detection, switching, and MPPT operation. The proposed IC provides an output power of up to 119 $\mu \text{W}$ with an end-to-end peak efficiency of 82% by consuming 582 nW.

Response Analysis of A Heat-absorbing Tower under Near-field Earthquake

In order to better study the impact of near-field vibration pulse effects on high-rise structures, a random point source method and an equivalent velocity pulse superposition method were used to generate 26 multi-environmental near-field vibration samples with pulse effects for 7-degree fortification. Through the finite element modeling and analysis, the vibration type of the light and heat tower structure is obtained, and the seismic response of the heat absorption tower is analyzed by the generated random ground motion, and the mean value and variance of the structure dynamic amplification factor, base shear force and displacement angle are obtained. Coefficient of variation. The results show that the random seismic response of the structure shows an obvious discrete type, the dispersion of the acceleration amplification factor increases with the height of the tower, the displacement response increases with the height of the tower, and the steel structure on the top of the tower has a significant whiplash effect.