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Advancements of virtual reality technology pave the way for developing wearable devices to enable somatosensory sensation, which can bring more comprehensive perception and feedback in the metaverse-based virtual society. Here, we propose augmented tactile-perception and haptic-feedback rings with multimodal sensing and feedback capabilities. This highly integrated ring consists of triboelectric and pyroelectric sensors for tactile and temperature perception, and vibrators and nichrome heaters for vibro- and thermo-haptic feedback. All these components integrated on the ring can be directly driven by a custom wireless platform of low power consumption for wearable/portable scenarios. With voltage integration processing, high-resolution continuous finger motion tracking is achieved via the triboelectric tactile sensor, which also contributes to superior performance in gesture/object recognition with artificial intelligence analysis. By fusing the multimodal sensing and feedback functions, an interactive metaverse platform with cross-space perception capability is successfully achieved, giving people a face-to-face like immersive virtual social experience. Current wearable solutions for Virtual Reality (VR) have limitations of complicated structures and large driven power. Here, the authors report a highly integrated ring consisting of multimodal sensing and feedback units for augmented interactions in metaverse.

Multi-frequency vibrators have advantages in bulk materials processing but their design is usually complicated. This article presents the synthesis of design parameters of a two-frequency inertial vibrator according to the specified power characteristics. Based on the developed mathematical model, the parameters of variable periodic force is derived for two angular velocities 157, 314 rad/s and their ratios 0.5 and 2. In the case of the 0.5 ratio, the instant angular velocity of the resulting force vector is 2.0–3.5 times greater than for ratio 2. A dynamical model of vibrating screen with the synthesized inertial drive is considered. It was found that at the ratio of angular velocities 0.5, the second harmonic of acceleration prevails at 50 Hz, while at the ratio of 2, the first harmonic has a greater amplitude at 25 Hz. For the first variant, the power does not depend on the initial angle between unbalances, and at the second variant, it can vary. The angle of rotation of unbalances affects the trajectory of the centre of mass and the phases of the harmonics but does not affect their amplitude. Due to such dynamical features, the two-motor inertial drive allows the vibrating machines to operate at a wider range of frequencies and amplitudes.

A vibration mechanism with asymmetric vibrations is discussed in the article. The mechanism consists of two stages of vibration blocks with directional vibrations. The asymmetric vibrations nature is estimated by the driving force components magnitude acting in opposite directions. The article deals with the obtaining rational parameters issue of a vibration mechanism with asymmetric vibrations, using the vibration mechanism dynamic factor. The vibration mechanism dynamic factor is numerically equal to the driving force largest component magnitude ratio to the smallest acting in the opposite direction. The work solves the following problems: - obtaining the vibration mechanism dynamic factor maximum value with asymmetric oscillations at the driving force largest component given value; - the conditions determination for reaching its maximum by the dynamic coefficient; - the conditions determination for obtaining the total driving force maximum value of the vibration mechanism with asymmetric vibrations, consisting of several stages of vibrators with directional vibrations.

To examine the influence of piezoelectric ceramic placement on the power generation performance of piezoelectric vibrators, firstly, the strain and output voltage equations of the piezoelectric vibrator were analyzed and derived. Secondly, a piezoelectric cantilever beam model was constructed using SOLIDWORKS modeling software and imported into COMSOL Multiphysics simulation software for simulation. When the Z-axis-specified displacement of the free end of the cantilever beam was 1.8 mm and the piezoelectric ceramics were in different patch positions, the stress–strain and output voltage of the piezoelectric vibrator were simulated and analyzed using this software. The simulation results indicate that when the piezoelectric ceramic is positioned 0 mm from the fixed end, and a 7.5 g mass block is attached to the free end, the maximum output voltage of the piezoelectric vibrator reaches 21.6 V. Finally, an experimental platform was established to test the output characteristics of the piezoelectric vibrator at various patch positions of the piezoelectric ceramic. The experimental results demonstrate that the power generation of the piezoelectric vibrator improves when the piezoelectric ceramic is closer to the fixed end. Specifically, when the ceramic was positioned 0 mm from the fixed end with a 7.5 g mass block at the free end, the maximum output voltage was approximately 15.3 V, accompanied by an output current of 0.057 mA and an output power of 0.8721 mW.

Various vibration mechanisms are used as vibration exciters for the beneficial use of vibration. By the type of drive, vibration mechanisms are divided into mechanical, electromechanical, hydraulic, pneumatic, vacuum-compression, electromagnetic and magnetostrictive. They are designed to excite forced vibrations that provide the required technological effect. Vibrators and vibrating hammers are currently used for vibration drilling of shallow wells in soft rocks, for vibration-rotating drilling in rocky and semi-rock formations, for driving and removing casing pipes and eliminating accidents associated with stuck drilling at the bottom of the well. The structural scheme of the ground hydraulic hammer-pulsator is designed for drilling seismic wells, the striker of which is a two-stage piston. The piston is connected to the atmosphere; the large piston is for studying the influence of the hydraulic hammer-pulsator on the drilling efficiency is equipped with a valve that closes the channels of the large piston in the upper position, and opens - in the lower position. A schematic diagram of a surface hydraulic hammer is shown to study the effect of a hydraulic hammer-pulsator on the drilling efficiency.

Using vibration to consolidate concrete is a standard task when placing normal concrete, and dates back to the early 1900s. Since then, concrete vibrators have been optimized to provide efficient consolidation, which includes an increase in their vibration frequency up to 200 Hz. On the other hand, compared to the concrete of the early 1900s, modern concrete has also been improved by reducing the proportion of water content. Both have been changed, but the vibration energy transfer has not been quantitatively evaluated lately for the updated vibrators and modern concrete. Herein, the attenuation of concrete, assuming a cylindrical wavefront and exponential decay for P-wave propagation, is measured and quantified. As a result, it can be concluded that the attenuation coefficient of modern concrete is distributed from 1 to 3 [m.sup.-1]. The notional power density, the maximum vibration energy imposed by a conventional vibrator, is 100 to 300 W/m (3), excluding the instability of near-field liquefaction. Keywords: attenuation; consolidation; rheology; vibrator.

The widespread use of smartphones and smart wearable devices has created a great demand for vibrators with complex vibration patterns driven by simple circuits. In our previous studies, we observed that a filiform shape-memory alloy (SMA) wire will shrink and then return to its initial length, perfectly synchronizing with a given pulse current. Here, we developed a novel vibrator whose structure allows the micro-vibrations of an SMA wire to be amplified up to a recognizable level without directly touching the wire. The vibrator has the advantage of independently controlling its magnitude and frequency together with a simple driving circuit since it is directly driven by a frequency-modulated pulse current with a controlled duty ratio. We measured the power consumption and the acceleration generated by the vibrator. The results showed that the vibrator consumed only 4–77 milliwatts of power with a quick vibration response within 5 milliseconds, and the acceleration increased significantly in a duty ratio range of around 1%. Furthermore, user evaluations demonstrated that differences in the magnitude and frequency of the generated vibrations were sufficiently recognized when the vibrator was driven by different duty ratios and frequencies, and the vibrator provided various tactile and haptic sensations to users.

Using Brownian vibrators, we investigated the structures and dynamics of quasi-2d granular materials, with packing fractions ( ϕ ) ranging from 0.111 to 0.832. Our observations revealed a remarkable large-scale flocking behavior in hard granular disk systems, encompassing four distinct phases: granular fluid, flocking fluid, poly-crystal, and crystal. Anomalous flocking emerges at ϕ = 0.317, coinciding with a peak in local density fluctuations, and ceased at ϕ = 0.713 as the system transitioned into a poly-crystal state. The poly-crystal and crystal phases resembled equilibrium hard disks, while the granular and flocking fluids differed significantly from equilibrium systems and previous experiments involving uniformly driven spheres. This disparity suggests that collective motion arises from a competition controlled by volume fraction, involving an active force and an effective attractive interaction resulting from inelastic particle collisions. Remarkably, these findings align with recent theoretical research on the flocking motion of spherical active particles without alignment mechanisms. An experimental method is needed to measure the effective interparticle attraction resulting from inelastic collisions for a quantitative study of non-equilibrium systems. In this study, the authors report the large-scale collective motion of non-polar particles and identify the phase transition point between the granular fluid phase and the collective fluid phase.

Shear phonons are collective atomic-layer motions in layered materials that carry critical information about mechanical, thermal and optoelectronic properties. Phonon branches with co-directional atomic-layer motions carry unique information about the global structure and hidden interfaces in layered crystals and heterostructures, but they are not detectable due to the very limited electron–phonon coupling. Here we utilize the propagating feature and mechanical coupling between shear phonons and localized plasmonic cavities to successfully realize direct characterization of ground-state shear phonons down to 4 cm−1 in energy by introducing mechano-Raman spectroscopy (MRS). MRS has the ability to characterize the global crystal structure with more than 108-fold enhancement and to accurately measure subpicometre displacements under ambient conditions with a thermal-noise-free feature. The propagating behaviour and the capacity of MRS to detect optically hidden interfaces are demonstrated. The broad tunability of plasmons makes the MRS technique a robust tool for extensive applications, including global crystal flaw detection, mechanical sensing and the mechanical modulation of light.Mechano-Raman spectroscopy is demonstrated by using interlayer phonons of atomic-layer vibrators to drive synchronous motion of the metallic plasmonic structure that can then be detected. The modulated light scattering brings out the information that cannot be accessed by optical Raman spectroscopy.

The isolation vibration design for a self-synchronous vibrating system is challenging because the realization of the system’s function depends on itself vibrating. We propose a method to solve the problem of vibrating isolation of the vibrating system, which is the realization of the self-balance function of the system from the perspective of self-synchronization. In the current study, a vibrating system with five rigid frames (RFs) driven by four vibrators is proposed to study its synchronization, stability, and self-balance characteristics. Utilizing the average method and Routh–Hurwitz stability criterion, the theoretical conditions of synchronization, stability, and self-balance of the system are obtained, respectively. Based on these three conditions, the stability and self-balance characteristics of the system in the different resonant regions are qualitatively analyzed in numeric, and the reasonable parameters matching principle of the system in realizing the synchronous stable operation with the function of self-balance is defined. A series of numerical simulations and experiments are further given to examine the correctness of the theoretical derivation and the rationality and practicability of the design of the mechanical system. The present work can be applied to the design of a new kind of vibrating machine, in which the working rigid frames can work with their circular motion trajectory, and the isolated rigid frame can remain stationary with around zero amplitude.