Ultrasound Vibration Research Articles

Broad spectrum catalysis using Ca3Sn2S7 Ruddlesden-Popper perovskite under multi-stimulus

Advanced oxidation processes emerged as effective alternatives to traditional approaches. The efficacy of these methods significantly depends on the intrinsic properties of a catalyst material. Semiconductor materials with robust photo absorption alongside inherent polarization emerged as subjects of great interest. In this study, we synthesized two-dimensional Ca3Sn2S7 nanosheets oriented as Ruddlesden-Popper type perovskite structure. The optimal compositions of these nanosheets exhibit excellent physical and optical characteristics while varying Sn ratios significantly impact the properties. Impressively, these compositions boast a wide optical window that spans from the visible to the far infrared region, featuring a narrow bandgap of approximately 0.6 eV. Band potentials in a positive regime make it highly favorable for the oxidation process. The electrochemical analysis further validates high mobility with low resistance in both compositions. The catalytic efficiency of the synthesized nanosheets is evaluated using rhodamine-B. Three energy sources, i.e., visible light, laser, and ultrasound vibrations, decomposed 96 %, 90 %, and 78 %, respectively, in 30 min. Remarkably accelerated degradation rates are achieved under each stimulus, owing to the presence of oxidative optical bands, large surface area, and potential internal polarization within the nanosheets. Preliminary findings strongly indicate the immense potential of this compound in catalytic and photovoltaic applications.

An efficient ultrasound vibration strategy for suppressing intra-bundle pores and regulating pore morphology in carbon fiber-reinforced composites

The competitive resin flow between intra- and inter-bundles, always causes the generation of intra-bundle pores during resin transfer molding (RTM), thereby weakening composite mechanical performance. Accordingly, an ultrasound vibration strategy is originally developed to efficiently suppress and improve the spatial morphology and distribution of intra-bundle pores in RTM manufacturing. The effects of ultrasound vibration on the spatial evolution of intra-bundle pores are systematically investigated, furthermore, the suppression mechanisms of intra-bundle pores are revealed. Additionally, an empirical model that predicts porosity under ultrasound vibration, is established and well validated for the developed ultrasound vibration strategy, which provides a feasible path for effectively manufacturing composites. X-ray micro-computed tomography experiments verify that applying a short period of ultrasound vibration balances the dual-scale flow by regulating the modified capillary number, thereby significantly reducing porosity by up to 59.4 %. Numerical analyses indicate that the acoustic cavitation and acoustic flow induced by the ultrasound vibration, facilitate the collapse and transverse migration of larger bubbles, thereby remarkably suppressing the connected pores and larger pores. In particular, the ultrasound vibration strategy completely removes the pores larger than 300 μm. Besides, the collective effects of vibration, compression, and shear forces contribute to forming near-circular pores, which are beneficial for ensuring the expected mechanical performance of composites.

Focus control of a concave–convex ultrasonic gel lens in the radial direction

Optical image stabilization (OIS) systems maintain the three-dimensional focal position of a lens through mechanical actuation systems. This paper examines an optical lens for OIS that utilizes ultrasound vibration to alter the focal position, not only in the depth direction but also in the radial direction. The lens has a simple structure with no mechanical moving parts and consists of an ultrasound transducer divided into four pieces, a glass disk, and a transparent viscoelastic gel film that functions as a lens. The acoustic radiation force generated by the resonant flexural vibration of the glass disk can alter the surface profile of the gel film, allowing for a variable-focus function. The concave and convex lenses can be interchanged using two resonant vibration modes: the standing-wave mode, in which the vibration loop appears at the center, and the traveling-wave mode, in which the vibration node appears at the center. The positions of ultrasound vibrations on the lens can be controlled in a two-dimensional plane by adjusting the driving amplitudes of each channel, thereby achieving focus control in the radial direction. The focusing characteristics of the lens are evaluated through ray-tracing simulation.

Phosphorus heteroatom doped BiOCl as efficient catalyst for photo-piezocatalytic degradation of organic pollutant and unveiling the mechanism: Experiment and DFT calculation

A novel phosphorus heteroatom doped bismuth oxychloride (P-BiOCl) catalyst was synthesized and the photo-piezocatalytic degradation of rhodamine B dye performances were explored under the ultrasound vibration and light illumination. The P-BiOCl exhibited excellent photo-piezocatalytic degradation activity, such as an ultra-high reaction kinetic rate constant of 0.3961 min−1, efficient degradation efficiency (94.7 % within 8 min) and excellent stability compared to solely piezocatalysis and photocatalysis. More impressively, these outstanding performances of P-BiOCl exceeded pure BiOCl and most other catalytic materials systems. The relevant experimental and density functional theory (DFT) calculation results were exhibited to clarify enhanced photo-piezocatalytic mechanism. The introduction of P heteroatom could reduce the bandgap of BiOCl, modulate electronic structure and charge redistribution, provide novel electron channel to promote electron transfer and restrain charge carriers recombination. Additionally, P-doped could also enhance the adsorption of oxygen and water molecules, promote intrinsic catalytic activity, leading to the increased production of active free radicals ·O2– and ·OH, thus significantly boosting the efficiency of organic pollutant degradation. This work provides a comprehensive understanding of heteroatom doping enhancing photo-piezocatalytic activity and presents a potential new strategy for designing highly efficient catalysts for wastewater treatment.

Ultrasonic vibration assisted directed energy deposition of titanium alloy: Microstructure control, strengthening mechanisms and fatigue crack behavior

Large-scale titanium alloy structural components fabricated using direct energy deposition (DED) technology have broad application prospects. However, the columnar grain structures and inhomogeneous microstructure due to the inherent characteristics of additive manufacturing seriously affects the mechanical properties of components. In this study, high-intensity ultrasound vibration was introduced into the wire-arc DED deposition of TC4-DT titanium alloy. The results showed that ultrasonic vibration assistance (UVA) significantly improves the grain structure (refine prior-β grain size and weaken α texture) of the as-deposited component, without introducing additional porosity. Compared to conventional wire-arc DED deposited components, the yield strength and tensile strength of UVA alloys increased by 22.23 % and 15.06 %, respectively. Furthermore, the difference in α grain structure caused by UVA results in different fatigue crack growth behaviors. The disorder orientation of the α laths enhanced the fatigue crack initiation resistance of the wire-arc DED component with UVA. This study shows the excellent mechanical properties of UVA DED fabricated TC4-DT alloy, paving the way for the design, fabrication, and application of large structural components of titanium alloys.

Ultrasonic aperture-tunable gel lens

Conventional camera modules require mechanical moving parts to move their lenses and to adjust their focal points. This paper examines optically tunable lenses with a focal length and lens aperture that can be controlled using ultrasound vibration and a transparent gel. The lens uses the acoustic radiation force, which induces changes in the lens profile; varifocal convex and concave lenses can be fabricated by adjusting the input signals. The optical characteristics of the lenses were evaluated using ray tracing simulations. The aperture can be controlled with the driving frequency, with higher frequencies leading to a wider range of focal length changes with a lower input voltage.

Numerical Simulation of Rock Vibration Response under Ultrasonic High-Frequency Vibration with High Confining Pressure

As deep oil and gas resources and Carbon Capture and Storage (CCS) are developed, enhancing drilling efficiency in hard rock formations has emerged as a critical technology in oil and gas extraction. The advancement of ultrasonic, high-frequency vibration rock-breaking technology significantly facilitates efficient rock crushing. When subjected to ultrasonic high-frequency vibrations, the rock’s response is a crucial issue in implementing ultrasonic vibration rock crushing technology. This study employed numerical simulation and theoretical deduction methods, utilizing a multi-physics approach that couples solid mechanics with pressure acoustics. It integrated information on common influencing parameters of ultrasonic generators and reservoir rock properties to establish model parameters, analyze simulation results, and perform theoretical deductions. The research investigated the response patterns of different-sized rock samples under high-frequency ultrasound vibration excitation across various frequencies, amplitudes, and confining pressure conditions. Through the development of a three-dimensional model and the application of principles from solid mechanics and elastoplasticity, the study derived equations that describe the resonance frequencies of rock blocks under confining pressure as functions of relevant rock parameters. The findings indicate that ultrasonic vibrations can effectively induce rock displacement. Under excitation frequency sources, the rock exhibits a natural frequency correlated with the rock sample size. When the excitation frequency approximates the natural frequency, the rock resonates. At this point, the rock’s surface displacement is maximal. The rock undergoes tensile stress, leading to stress concentration that facilitates rock damage and fragmentation. Increasing the excitation amplitude enhances rock crushing, as it amplifies the maximum surface displacement under the same frequency excitation. Confining pressure exerts an inhibitory effect on the rock’s vibration response, but it does not alter the resonance frequency of the rock sample, a fact verified by both numerical simulation and theoretical results. Based on the research findings in this paper, it can help to optimize the parameters of ultrasonic vibration rock breaking in field application to achieve the best rock-breaking effect.

Bioactive Nanotherapeutic Ultrasound Contrast Agent for Concurrent Breast Cancer Ultrasound Imaging and Treatment.

Contrast-enhanced ultrasound (CEUS) plays a crucial role in cancer diagnosis. The use of ultrasound contrast agents (UCAs) is inevitable in CEUS. However, current applications of UCAs primarily focus on enhancing imaging quality of ultrasound contrast rather than serving as integrated platforms for both diagnosis and treatment in clinical settings. In this study, a novel UCA, termed NPs-DPPA(C3F8), is innovatively prepared using a combination of nanoprecipitation and ultrasound vibration methods. The DPPA lipid possesses inherent antiangiogenic and antitumor activities, and when combined with C3F8, it functions as a theranostic agent. Notably, the preparation of NPs-DPPA(C3F8) is straightforward, requiring only one hour from raw materials to the final product due to the use of a single material, DPPA. NPs-DPPA(C3F8) exhibits inherent antiangiogenic and biotherapeutic activities, effectively inhibiting triple-negative breast cancer (TNBC) angiogenesis and reducing VEGFA expression both in vitro and in vivo. Clinically, NPs-DPPA(C3F8) enables simultaneous real-time imaging, tumor assessment, and antitumor activity. Additionally, through ultrasound cavitation, NPs-DPPA(C3F8) can overcome the dense vascular walls to increase accumulation at the tumor site and facilitate internalization by tumor cells. The successful preparation of NPs-DPPA(C3F8) offers a novel approach for integrating clinical diagnosis and treatment of TNBC.

Investigation on the micro-cutting mechanism of aluminum matrix composites with ultrasound elliptical vibration

Investigation on the micro-cutting mechanism of aluminum matrix composites with ultrasound elliptical vibration

An ultrasound-assisted resin transfer molding to improve the impregnation and dual-scale flow for carbon fiber reinforced resin composites

The imbalance of the dual-scale flow, i.e., microscopic intra-bundles and macroscopic inter-bundles flow, always generates voids in resin transfer molding (RTM) of composites, substantially weakening the mechanical performance. An ultrasound-assisted strategy to improve the impregnation and to balance dual-scale flow is promising to suppress the voids, while, it has still not been explored. Here, an ultrasound-assisted RTM for carbon fiber reinforced resin composites, realized by a self-developed device, is originally proposed. The influences of ultrasound vibration on the carbon fibers, resins, wettability, and impregnation process are systematically explored. Furthermore, the dual-scale flow, affected by the ultrasound vibration, is optimized. It is identified that the ultrasound vibration effectively reduces the viscosity of the resin and increases the roughness and surface activity of the fibers, hence significantly weakening the delayed impregnation in the intra-bundles, and speeding up the impregnation velocity in the inter-bundles. The reduction of the viscosity and the contact angle synergistically lowers the modified capillary number Ca*, hence balancing the dual-scale flow, while the excessively high impregnation velocity in the inter-bundles detrimentally enlarges Ca*, leading to the imbalance of the dual-scale flow. Accordingly, a critical ultrasound energy input (4 min of ultrasound vibration at the power range of 400–600 W) is figured out to achieve an optimal Ca*, providing a promising approach to suppress the flow-induced voids in composites manufacturing by RTM.

In-situ sonochemical formation of N-graphyne modulated porous g-C3N4 for boosted photocatalysis degradation of pollutants and nitrogen fixation

Herein, Nitrogen-doped graphyne/porous g-C3N4 composites are firstly in-situ synthesized via the ultrasound vibration of CaC2, triazine, and porous g-C3N4 in absolute ethanol. A variety of characterizations are performed to investigate the morphology, microstructure, composition, and electrical/optical features of the obtained composites, such as transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectra, X-ray photoelectron spectroscopy, and so forth. It is found that N-doped graphyne with flexible folds lamellar structure is intimately attached to flake g-C3N4 in the as-prepared composites. An enlargement of 1.68 and 1.44 folds for the photocatalytic degradation of levofloxacin, rhodamine B, Methylene blue, and Tetracycline is realized by N-doped graphyne/g-C3N4 in comparison with that of pristine g-C3N4, respectively. In addition, the highest NH3 production rate attains 1.71 mmol⋅gcat−1⋅h−1 for N-doped graphyne/g-C3N4, which is 5.89 times larger than that of g-C3N4 (0.29 mmol⋅gcat−1⋅h−1). The improved mechanism of photocatalysis including higher photo-response and carrier separation rate is verified by transient photo-current, transient photo-potential, Mott-Schottky plots, Tafel plots, electrochemical impedance spectroscopy, turn-over frequency, photoluminescence spectra, and UV–vis diffuse absorption spectra, etc. Overall, the current study shows that N-doped graphyne synthesized from CaC2 and triazine is a useful decoration to modulate the photocatalytic features of g-C3N4, which can also be widely extended for in-situ modification of other photocatalysts.

Integration of hydrogen evolution and dye removal in flexocatalysis by centrosymmetric semiconductor nanorods

In this work, coupling of the hydrogen (H2) production and dye degradation was first realized in a single flexocatalytic process using cerium oxide nanorods (CeO2 NRs). The flexoelectric polarization in a bending nanorod created an internal electric field, which promoted the separation of the thermal-excited electrons and holes. As a consequence, the H2 evolution rate of the flexocatalysis in dark was twice higher than that of the photocatalysis by the same CeO2 NRs. Moreover, simultaneous dye degradation was realized without reducing the H2 evolution rate, with the degradation constant rate of 0.065 min−1, dye removal efficiency of 89.3%, and H2 generation at 486.4 μmol g−1 h−1. The dual-functional catalytic performance of the CeO2 NRs was benefited from the unique periodic flexoelectric field induced by the ultrasound vibration, which could not be achieved by photocatalysis. This work revealed the important role of flexoelectric effect in overcoming the limitation in photocatalysis, which could be extended to a wide range of semiconductor nanomaterials for designing novel kinds of advanced flexocatalysts.

Characterization of Corrosion-Induced Fracture in Reinforced Concrete Beams Using Electrical Potential, Ultrasound and Low-Frequency Vibration

The paper deals with the non-destructive experimental testing of the reinforced concrete beams under progressive corrosion. A series of experiments using electrical potential, ultrasound and low-frequency vibrations techniques are reported. Electrical potential and natural frequencies were used to characterise and monitor the corrosion process at its initial state. The P-wave velocity measurements were proved to be effective in quantitative assessment of the level of corrosion as it progresses. The possibility of early detection of damage using a proposed damage index and diagnostic framework is promising for possible applications in the non-invasive diagnostics of reinforced concrete elements.

Micro-CT evaluation of the presence of voids in endodontic obturation.

To analyze by micro-CT the presence of voids in lower single-rooted premolar root canal obturations prepared using the single cone and ultrasound vibration technique. Twenty extracted single-rooted lower premolars were selected, and the root canal prepared surgically and chemically. In GROUP 1 - Without Vibration, the canal was obturated with a single cone and bioceramic, without applying vibration. In GROUP 2 - With Vibration, the gutta-percha cone inside the root canal was held with a cotton plier to which ultrasound vibration was applied for 3 periods of 3 seconds each. A micro-CT scanner was used to acquire and reconstruct images for analysis. No significant difference was found between obturation techniques, though there were differences between thirds, with the cervical third having a higher percentage of voids than the middle and apical thirds. The results suggest that the volume of closed, open and total voids does not differ between treatments with and without ultrasound vibration. In the cervical third, the highest volume of voids was related to oval geometry in the teeth evaluated.

Evaluating coal pore structure and gas sorption-diffusion behavior alteration induced by ultrasound stimulation using sorbing tests and matrix diffusion modeling

Coalbed methane development has great significance to ensure the safe and efficient coal mining, clean energy supplementation and carbon emission reduction. Ultrasound stimulation can effectively modify the coal pore/fracture structure and change the gas ad/de-sorption process and diffusion kinetics characteristics, thus altering gas production for coal deformations. This study estimated the pore structure damage and gas sorption-diffusion of coal before and after ultrasound stimulation with gas sorption tests and gas sorption-diffusion modeling. The results show that the maximum nitrogen adsorption capacity increases by 181.2%–218.9% in coal after ultrasound stimulation, and the pore volume and specific surface area of the ultrasound stimulated coals are 1.5–2.0 times and 5.6–7.6 times of those of the raw coals, respectively. Ultrasound stimulation (20 kHz) has a significant modification effect on pores with size of 2∼50 nm. Fractal analysis of pore structure indicates that the pore surface roughness reduces after the ultrasound treatment, and the development of coal pores has become more complex, and the pore heterogeneity has increased with ultrasound stimulation. The sorption tests and gas sorption-diffusion modeling indicate that gas sorption and diffusive transportation increases after the ultrasound treatment, especially in the initial period. In the initial pressure boosting stage (0∼0.5 MPa), the cumulative methane adsorption amount increases by 20.94%, the diffusion coefficient K increases by 17.32%, and the gas adsorption constant b increases by 62.66%, which is attributed to the “pore-forming” and “pore-expanding” effect caused by ultrasound vibration and cavitation. Ultrasonic stimulation technology has a special improvement performance on coal seams with poor matrix gas deliverability, which is beneficial for the life cycle production enhancement of coalbed methane wells.

Agglomerating behavior of in-situ TiB2 particles and strength-ductility synergetic improvement of in-situ TiB2p/7075Al composites through ultrasound vibration

Agglomerates of in-situ particles are the key detrimental defects in particulate reinforced aluminum matrix composites (PRAMCs) by acting as Achilles' heel leading to the premature failure of the materials. Effective methods to disperse/eliminate these agglomerates rely on in-depth understanding of the agglomeration mechanism of the in-situ particles. In this work, the agglomerating behavior of TiB2 particles in Al-Ti-B system was investigated through the thermit reactions between mixed fluorides and molten aluminum. The results indicate that the morphological patterns of TiB2 agglomerates are inherited from the preformed Al3Ti intermedium. The formation of flocculent, shell and flaky TiB2 agglomerates are the results of the diffusing boron atoms continuously reacting with Al3Ti. The in-situ Al-TiB2 was used as a precursor to prepare TiB2p/7075 Al composites. In particular, ultrasound vibration treatment was applied to explore if a locally forced oscillation can deagglomerate the TiB2 agglomerates. Microstructural observations strongly support such speculation. Thanks to the deagglomeration and dispersion of TiB2 particles, both the strength and ductility of the PRAMC have been improved drastically. The fracture surface of the composites was transformed from particle debonding to the dominance of ductile fracture.

Acousto-thermal birefringence of iron(III) chloride using ultrasound flexural standing wave

Abstract Small, thin devices that can realize high-speed light modulation are important in the imaging and sensing technology fields. In this paper, a combination of iron(III) chloride and ultrasound was proposed to modulate the spatial distribution of the iron(III) chloride layer’s refractive index. An ultrasound cell containing an iron(III) chloride layer and two ultrasound transducers was fabricated to investigate the variations in the refractive index under ultrasonication. The maximum change in the material’s birefringence was observed at the center of the cell, indicating that thermal generation caused by the ultrasound vibration induced this phenomenon.

Soft ferroelectret ultrasound receiver for targeted peripheral neuromodulation

Bioelectronic medicine is a rapidly growing field where targeted electrical signals can act as an adjunct or alternative to drugs to treat neurological disorders and diseases via stimulating the peripheral nervous system on demand. However, current existing strategies are limited by external battery requirements, and the injury and inflammation caused by the mechanical mismatch between rigid electrodes and soft nerves. Here we report a wireless, leadless, and battery-free ferroelectret implant, termed NeuroRing, that wraps around the target peripheral nerve and demonstrates high mechanical conformability to dynamic motion nerve tissue. As-fabricated NeuroRing can act as an ultrasound receiver that converts ultrasound vibrations into electrostimulation pulses, thus stimulating the targeted peripheral nerve on demand. This capability is demonstrated by the precise modulation of the sacral splanchnic nerve to treat colitis, providing a framework for future bioelectronic medicines that offer an alternative to non-specific pharmacological approaches.

Suppression of low-frequency ultrasound broadband vibration using star-shaped single-phase metamaterials

In order to suppress the low-frequency ultrasound vibration in the broadband range of 20 kHz–100 kHz, this paper proposes and discusses an acoustic metamaterial with low-frequency ultrasound vibration attenuation properties, which is configured by hybrid arc and sharp-angle convergent star-shaped lattices. The effect of the dispersion relation and the bandgap characteristic for the scatterers in star-shaped are simulated and analyzed. The target bandgap width is extended by optimizing the geometry parameters of arc and sharp-angle convergent lattices. The proposed metamaterial configured by optimized hybrid lattices exhibits remarkable broad bandgap characteristics by bandgap complementarity, and the simulation results verify a 99% vibration attenuation amplitude can be obtained in the frequency of 20 kHz–100 kHz. After the fabrication of the proposed hybrid configurational star-shaped metamaterial by 3D printing technique, the transmission loss experiments are performed, and the experimental results indicate that the fabricated metamaterial has the characteristics of broadband vibration attenuation and an amplitude greater than 85% attenuation for the target frequency. These results demonstrate that the hybrid configurational star-shaped metamaterials can effectively widen the bandgap and realize high efficiency attenuation, which has capability for the vibration attenuation in the application of high-precise equipment.

Effect of ultrasonic vibration on the orientation of C2C12 cells

Control of orientation direction of tissues is important for regenerative medicine techniques. This paper investigates effects of ultrasound vibration on a culture dish on the orientation of myoblast C2C12 cells. A piezoelectric ultrasonic transducer (PZT) was fixed to the bottom of a culture dish. A continuous sinusoidal signal with 10 to 30 Vpp at the resonant frequency of 86kHz was input to the transducer to generate a concentric flexural vibration mode on the bottom surface of the dish. C2C12 cells were cultured on the dish for 2 days under continuous ultrasonic vibration. The ultrasound excitation was then stopped, resulting in the differentiation of the cells into myotube cells through 7 days. The orientation distribution of the cells on the dish was evaluated by spatial Fourier transform in the microscopic images. Compared with the control, the orientation of C2C12 cells was changed significantly under ultrasonication; the concentric pattern of the cell orientation appeared, which corresponds to the concentric vibration mode generated on the bottom of the dish. Larger vibrational amplitude of the dish gave a larger effect on the cell orientation.