Ultrasonic Technology Research Articles

A Miniature PMUT Array for Medical Applications

Abstract Wearable continuous monitoring technology and internal and cerebrovascular imaging are the frontier hot area of current scientific research, which are of great significance to improving human life and health. Ultrasonic imaging can obtain information such as deep tissue structure by transmitting ultrasonic waves into the tissue and detecting echo signals, and ultrasonic imaging technology has the advantages of high imaging depth, high resolution, high safety, fast and convenient, etc. It is one of the important technologies in the medical field such as wearable continuous monitoring technology and internal cardiovascular and cerebrovascular imaging. But miniaturization and low power consumption are necessary conditions for the success of such medical applications. Therefore, the ultrasonic imaging technology using a miniature ultrasonic probe is one of the most promising imaging technologies for this type of medical application. Aiming at the common technical problems of traditional ultrasonic transducers such as large volume, narrow bandwidth, high power consumption, difficulty in preparing two-dimensional arrays, and difficulty in integrating with ICs. In this paper, the electromechanical-acoustic multi-field coupling mechanism and array structure design technology of MEMS high-performance PMUT ultrasonic transducer elements are first studied, and a CMOS-compatible miniature PMUT high-performance array ultrasonic device suitable for this type of medical application is developed. The simulation results of the transducer are given. The measurement of various physical parameters of the transducer sample and the results of its application in the ultrasonic imaging system show that the miniature PMUT linear array ultrasonic sensor we designed is a kind of high performance ultrasonic array sensors that can be widely used in wearable continuous monitoring technology and internal cardiovascular and cerebrovascular imaging.

Defect recognition and classification from ultrasonic phased array total focusing method imaging based on domain adaption

Abstract With the rapid development of China’s economy, the demand for oil and gas resources is continuously increasing, leading to the expansion of the scale of oil and gas long-distance pipelines. Consequently, the risk of safety incidents in oil and gas pipelines is on the rise. Welding defects are identified as one of the significant factors contributing to safety incidents in long-distance oil and gas pipelines. In comparison to traditional conventional ultrasonic detection techniques, which exhibit low efficiency and accuracy, ultrasonic phased array detection technology has the capability to accurately detect welding defects in oil and gas long-distance pipelines. This is particularly true with the development of total focusing method imaging technology, enabling quantitative defect analysis and localization in oil and gas long-distance pipelines.However, in the current scenario, analyzing the types of defects in massive data from long-distance pipelines requires human intervention, leading to low detection efficiency and subjective influence on result analysis. Addressing challenges such as low efficiency in human evaluation of defects in ultrasonic phased array detection, low accuracy in traditional image recognition methods, strong subjectivity in manually extracting features, and the absence of a standardized industrial dataset for ultrasonic phased array detection defects, especially in the case of limited data on ultrasonic phased array detection of welding defects, this study focuses on small sample defects in phased array detection images. The study proposes an improved ResNet50 algorithm through domain adaptation in a deep neural network, trained on a large-scale model data, and then applied to ultrasonic phased array detection data. This approach achieves accurate identification and classification of typical volumetric defects (such as pores) and typical area defects (such as cracks) in the phased array detection of welding defects, laying the foundation for intelligent recognition of defects in long-distance oil and gas pipelines.

Study on ultrasonic lamb wave testing technology of honeycomb sandwich structures

Abstract Honeycomb sandwich composite panels have complex structures, large sizes, many types of defects, and significant sound attenuation, which lead to low efficiency and poor sensitivity of ultrasonic non-destructive testing. In the study, a non-linear ultrasonic lamb wave testing technique for honeycomb sandwich composite panels is proposed. Firstly, the anisotropic propagation characteristics and modal structure of lamb waves in honeycomb sandwich composite panels are analyzed, and the lamb wave modes with non-linear ultrasonic accumulation are excited. Secondly, the data extraction method and imaging algorithm of non-linear ultrasonic lamb wave imaging testing are proposed. Finally, an enhanced imaging algorithm is proposed to improve image quality based on the sliding window algorithm. Based on the comparative analysis of air-coupled ultrasonic testing images and metallographic tests, it can be seen that non-linear ultrasonic lamb wave testing signals can be used to characterize the damage distribution characteristics of honeycomb sandwich composite panels, display debonding and weak debonding defects, and have the advantages of being able to perform on the same side testing and high efficiency, which can be used for non-destructive testing of honeycomb sandwich composite panels.

Laser ultrasonic characterization of grains in titanium alloy by the inversion method

Abstract The polycrystalline materials have been usually described by the average grain size (AGS). This paper provides a nondestructive method for determination of the AGS in titanium alloy from an inversion of experimental ultrasonic attenuation spectrum (UAS). The detailed analyses of the inverse algorithm and sensitivity of UAS to the AGS are presented, and the sensitivity is identified as a criterion for selecting the experimental data of UAS used in inversion. An example of the inverse method and experimental measurement for UAS comparison was given for the titanium alloy specimen with the AGS of 26 μm. The relative error between the AGS determined by the inversion and scanning electron microscope (SEM) observation was found to be about 1.5 %. The provided method demonstrates the feasibility of laser ultrasonic technology used for the non-destructive evaluation of AGS in polycrystalline materials.

Mechanical properties and damage characterization of 310S steel using laser ultrasonic inspection under extreme temperature condition

Abstract To evaluate the mechanical properties of 310S stainless steel under extreme working conditions, and realize the damage characterization function, in this study, the longitudinal wave and Rayleigh wave of materials are measured by the method of coaxial inspection on reverse surface and ipsilateral ectopic inspection, respectively, and surface cracks and internal voids are detected by the scanning laser source technology and transmission scanning detection, respectively. The detection methods are designed based on the energy distribution characteristics of Rayleigh wave and longitudinal waves in laser ultrasound. The laser ultrasonic detection systems coupled with a temperature loading device (high temperature: vacuum chamber; low temperature: refrigerating chamber) developed by the laboratory enable on-site monitoring of laser ultrasonic technology in harsh environments. Experimental results demonstrate that the error in mechanical properties (elastic modulus, shear modulus, Poisson ratio) is less than 5% over a wide temperature range (-180-1000°C). At 1000°C, surface cracks wider than 0.5mm and deeper than 1.9mm as well as internal hole defects larger than 1.0mm can be detected with an error rate below 5%.

The impact of ultrasonic shock surface treatment technology on the microstructure, mechanical and corrosion properties of FeCrMnCuNiSi high-entropy alloy coating via TIG arc melting

The impact of ultrasonic shock surface treatment technology on the microstructure, mechanical and corrosion properties of FeCrMnCuNiSi high-entropy alloy coating via TIG arc melting

Battery state characterization based on a contactless electromagnetic ultrasound testing method

Nondestructive ultrasonic detection technology has been increasingly applied to battery diagnostics. However, currently used ultrasonic transducers must be affixed to the tested battery very tightly through coupling agents, thereby lowering the test efficiency and convenience. In this paper, a contactless electromagnetic ultrasonic testing technology is proposed for characterizing the states of lithium-ion batteries. The relationship between the ultrasonic frequency and wave velocity is analyzed via a finite element model. Meanwhile, the influence of battery boundary characteristics on ultrasonic signals is investigated. Based on the propagation characteristics of ultrasonic guided waves in the battery, contactless electromagnetic acoustic transducers (EMATs) are designed and optimized. Three features, including the time of flight, signal amplitude, and energy integration, are extracted from the received signals to indicate the variation in battery state during charging and discharging cycles. Experimental results demonstrate that the ultrasonic guided wave features obtained from EMATs change consistently and regularly with the charging and discharging states of the battery. The proposed method can be used to analyze the aging of batteries and the inconsistency of electrolyte infiltration inside batteries, which is expected to improve the battery safety.

Enhancement of methane production from anaerobic co-digestion of food waste and dewatered sludge by thermal, ultrasonic and alkaline technologies integrated with protease pretreatment

Pretreatments to improve the efficiency of anaerobic digestion (AD) have gained more attention. The efficiency and mechanism of neutral protease (NP) integrated with other methods remain unclear. This study investigated the efficacy of thermal, alkaline and ultrasonic technologies integrated with NP as the pre-treatments for AD of food waste and dewatered sludge. Results showed the thermal method integrated with NP (TH-NP) was the most effective, achieving a 104.2% improvement in methane production. In this case, TH-NP increased soluble chemical oxygen demand and protein concentrations by 8.6% and 39.8%, respectively. Microbial community analysis indicated that TH-NP promoted the symbiosis between Woesearchaeales and hydrogenotrophic methanogenesis. Furthermore, the PICRUSt2 analysis revealed that TH-NP increased the activities of most enzymes in the acetate and propionate metabolic pathways. In summary, TH-NP is more effective in increasing the AD efficiency compared to other combined pretreatments. This study provides theoretical support for protease-induced pretreatment technology.

Feedback system for reactor process analysis

The article discusses an approach to analyzing processes in industrial reactors using advanced systems with feedback. The authors describe the system preparation and image reconstruction algorithms of ultrasonic tomographs (USTs) that have applications in industry. The research presented in this paper focuses on developing effective strategies for controlling and monitoring chemical reaction processes in reactors. Using advanced data processing techniques, the authors propose systems with feedback that enable accurate analysis and optimization of reactor operating conditions. A key aspect is ultrasonic tomographic imaging, which provides precise data on the state of the process in the reactor. In summary, the paper presents a state-of-the-art approach to analyzing chemical reaction processes in industrial reactors using advanced feedback systems and ultrasonic imaging technologies. The proposed solutions are essential for improving efficiency and process control in the chemical industry.

The behavior and model of methane adsorption on coal by ultrasonic enhancement

Ultrasonic technology can effectively improve the efficiency of coalbed methane (CBM) extraction and holds a broad application prospect. While the influence of the ultrasonic comprehensive effect on CBM output has been extensively studied, there is still a lack of in-depth discussion and detailed analysis of the specific influence of the single effect on methane adsorption. This article conducted an in-depth study of methane adsorption behavior in three different ways: ultrasonic comprehensive effect (UCE), thermal effect (UTE), and mechanical vibration effect (UMVE) by controlling the experimental conditions. The results indicated that CH4 adsorption was significantly inhibited by the UCE, and this inhibition was mainly influenced by the UTE. In contrast, the UMVE somewhat enhanced the adsorption of CH4. The moisture in the coal did not change the above trend. Furthermore, the promotion of CH4 adsorption by UMVE had an immediate effect, occurring only when UMVE was applied. The essence of promoting adsorption is that UMVE acts on the coal matrix and CH4 adsorption phase as an additional load, subsequently resulting in an increase in adsorption equivalent pressure. Based on the above understanding, the equivalent pressure parameter of CH4 adsorption under UMVE was proposed, and a mathematical model for CH4 adsorption under UMVE was constructed. In addition, a CH4 adsorption model under the UCE was established. The research results have certain reference significance for the application of ultrasonic in coalbed methane mining.

Study on Denoising Method of Weld Defect Signal Based on SSA-VMD-WPD

Defects in welds can affect the structural safety and reliability of workpieces. Currently, the method of using phased array ultrasonic inspection technology for non-destructive testing of weld structures with high detection efficiency, good sensitivity, and good visualization of the results is widely used. However, the defective A-scan data collected by the ultrasonic phased array detector inevitably contain noise data, including the test piece material structure noise, equipment noise, and environmental noise, which undoubtedly affects the analysis of the A-scan signal. In addition, when defects are interpreted, the presence of noise also interferes with the process, which affects the accuracy of the interpretation. Therefore, to enhance the accuracy of defect identification based on phased array ultrasonic inspection technology, we must prevent the series of consequences caused by misjudgments. In this study, ultrasonic phased array inspection experiments were carried out, and the specific process flow of ultrasonic phased array inspection of flat plate butt welds was summarized. Utilizing pre-fabricated flat plate butt specimen blocks containing five types of typical defects, defect A-sweep signals based on ultrasonic phased array inspection were obtained. Combining the sparrow optimization algorithm (SSA), variational mode decomposition (VMD), and wavelet packet decomposition (WPD), a defect signal noise reduction method based on parameter optimization was studied. A noise reduction study was carried out using the noise-added simulated signal, and the results indicated that the noise reduction method proposed in this paper had a better noise reduction effect and the proposed method could effectively retain the detailed features of the ultrasonic phased array defective A-scan signal and realize the noise reduction processing of the defective A-scan signal.

Bactericidal effect of ultrasound on glutinous rice during soaking and its influence on physicochemical properties of starch and quality characteristics of sweet dumplings

The soaking process of glutinous rice allows the growth and reproduction of microorganisms, which can easily cause food safety problems. In this work, the effects of different ultrasonic powers (150 W, 300 W, 450 W, and 600 W) on the bactericidal effect of glutinous rice, the physicochemical properties of starch and the quality characteristics of sweet dumplings were studied. Compared with soaking for 0 and 2 h, sonication of glutinous rice after soaking for 4 h was more effective at reducing the number of microorganisms in soaked glutinous rice, and the bactericidal effect increased with increasing ultrasound intensity. After 30 min, the total number of bacteria decreased by 2.04 log CFU/g. Moreover, ultrasonic treatment destroys the grain structure of glutinous rice starch, resulting in the formation of dents and cracks on the starch surface, increasing the amylose content, improving its expansion, reducing its short-range order and relative crystallinity, and altering its gelatinization characteristics. In addition, ultrasonic treatment increased the soup transparency of sweet dumplings from 51.8 % to 63.95 %, reducing their hardness, chewiness and adhesiveness. In summary, ultrasonic treatment can not only effectively kill microorganisms in soaked glutinous rice but also improve the quality of glutinous rice dumplings by changing the physicochemical properties of glutinous rice starch. The results of this study provide theoretical support for the application of ultrasonic technology in glutinous rice food production.

Nondestructive evaluation of debonding in composites using air-coupled coda wave analysis and local defect resonance techniques

Abstract Low acoustic energy conversion efficiency is a major challenge for air-coupled ultrasonic technology. In the determination of the lift-off distance of air-coupled sensors, there is a balance between the acoustic energy attenuation and the difficulty of extracting defect information. In this study, an air-coupled local defect resonance (LDR) technique with coda wave analysis is proposed for the nondestructive evaluation of debonding in composites. A sensor consisting of 19 elements was used to simultaneously excite and receive ultrasonic waves. Air-coupled LDR experiments were conducted on the two types of composite structures. The effects of sensor lift-off distance and coda wave analysis on the performance of the LDR technique were investigated. It was found that the sensor lift-off distance and the coda wave analysis had a significant effect on the defect detection capability of the LDR technique. For composites, the optimal sensor lift-off distance was found to be between 3.5λ and 5.5λ, where λ is the wavelength. Compared to multiple reflection echoes, the coda waves are more suitable for identifying the damage in composites. The proposed non-contact ultrasonic technique effectively reduces the required incident acoustic energy and can be used for efficient detection of debonding in composites.

Model for the Failure Prediction Mechanism of In-Service Pipelines Based on IoT Technology

With the rapid increase in pipeline mileage in China, the accurate prediction of corrosion issues in in-service pipelines has become crucial for ensuring safe pipeline operation. Traditional pipeline leakage monitoring methods are significantly limited by human factors and equipment precision, making it challenging to predict and identify leakage points accurately. Therefore, aligned with the trend of intelligent pipeline development, this study aims to construct a failure pressure prediction mechanism model for corroded pipelines based on IoT technology. This model leverages intelligent sensing and prediction to assess the safety status of corroded pipeline sections. Ultrasonic phased array technology detects specific corrosion points and detailed defect parameters within pipeline sections. The parameters are then utilized in the Simdroid domestic finite element analysis model to simulate the ultimate burst pressure of the pipeline. A single-variable approach is employed to analyze the sensitivity of different parameters to the pipeline’s ultimate burst pressure, with the minimum burst pressure point of multi-point corroded sections selected as the overall segment failure pressure. Finite element simulation data are integrated into a neural network database to predict the pipeline failure pressure. The real-time operational data of the pipeline are monitored using negative-pressure wave sensing. The operational pressure of the corroded points is compared with the algorithm-predicted failure pressure; if the values approach a critical threshold, an alarm is triggered. Moreover, the remote control terminals evaluate the pipeline’s self-rescue time, providing a buffer for pipeline leakage self-rescue. The failure prediction mechanism model for in-service pipelines was applied to the Fujian–Guangdong branch of the West–East Gas Pipeline III to verify its accuracy and feasibility. The research results offer technical support for the maintenance and emergency repair of pipeline leakage scenarios, leveraging intelligent pipeline technology to reduce costs and increase the efficiency of pipeline operations, thereby supporting the sustainable development of China’s oil and gas pipelines with theoretical and technical backing.

Broad bandwidth and excellent thermal stability in BiScO3-PbTiO3 high-temperature ultrasonic transducer for non-destructive testing

High-temperature ultrasonic transducer (HTUT) is essential for non-destructive testing (NDT) in harsh environments. In this paper, a HTUT based on BiScO3-PbTiO3 (BS-PT) piezoelectric ceramics was developed, and the effect of different backing layers on its bandwidth were analyzed. The HTUT demonstrates a broad bandwidth and excellent thermal stability with operation temperature up to 400 °C. By using a 10 mm thick porous alumina backing layer, the HTUT achieves a broad −6 dB bandwidth of 100 %, which is about 4 times superior to the transducer with an air backing layer. The center frequency (fc) of the HTUT remains stable with fluctuations of less than 10 % across the temperature range from room temperature to 400 °C. The HTUT successfully detected simulated defects in pulse-echo mode for NDT over 200 °C. This research not only advances high-temperature ultrasonic transducer technology but also expands the NDT applications in harsh environmental conditions.

Microstructure, joining mechanism, mechanical properties and optimization of inactive solder (Sn9Zn) in low temperature ultrasonic soldering of AlN ceramics and 2024Al

With the development of the electronic packaging industry, there is an increased demand for enhanced strength in DBA substrates. Ultrasonic soldering technology allows low-temperature joining of ceramic-metal materials under ambient air conditions. In this paper, we successfully achieved the joining between AlN ceramics and 2024Al using Sn9Zn solder and ultrasonic soldering technique, while also analyzing the joining mechanism through Comsol software simulations. It was observed that under the appropriate ultrasonic amplitude and frequency, the Sn9Zn solder exhibited complete wetting with both base materials, resulting in reliable joints. Building upon this finding, the conventional Sn9Zn solder was further optimized by adding Sb element. The addition of Sb element led to the formation of Zn4Sb3 phase and β-Sn(Sb) phase with Sb acting as solute. Among them, the generation of β-Sn(Sb) solid solution phase effectively improved the joint strength. The maximum joint strength was achieved at an average value of 75.066 MPa when the Sb content reached 1 wt. %. At this point, the failure occurred within the AlN ceramic base material.

Controlling algal growth using ultrasonic technology and conceptual implementation in the real-life system

ABSTRACT The present work reports a study on the interactive response of algae and other microorganisms coexisting in a natural water body to ultrasonic treatment for effective algal growth inhibition using ultrasonic treatments. The cellular damage caused by treatment was also visualised through SEM imaging. For an ultrasonic exposure of 10–30 min at 30 kHz frequency with ultrasonic power dissipated in the range of 4.2–12.5 W, the reduction in the algal cell density was changed from 37.82 to –52.73% after 7 days of observation period. The gradual decrease in the chlorophyll concentration signified the reduced photosynthetic activity after treatment. The damage created on the cell membrane by ultrasound was evaluated through the increased permeability of electrolytes from the cells and the rise in the conductivity of water. Following the lab-scale experimental studies and interpretation of the results obtained, field trials were carried out at a local natural pond (40*35 sq. metre) for 6 months and secondary clarifier in a local industry (20 m diameter) for 2 months, with some system working based on low power ultrasonic transmitters (power ∼ 25 W/h and frequency 20–40 kHz) and promising improvement in water quality could be observed with 85% and more than 95% algae removal efficiency, respectively.

Evaluating the Stability and Digestibility of Long-Chain Omega-3 Algal Oil Nanoemulsions Prepared with Lecithin and Tween 40 Emulsifiers Using an In Vitro Digestion Model.

The health benefits of long-chain omega-3 polyunsaturated fatty acid (LCn-3PUFA) intake have been well documented. However, currently, the consumption of oily fish (the richest dietary source of LCn-3PUFA) in the UK is far below the recommended level, and the low digestibility of LCn-3PUFA bulk oil-based supplements from triglyceride-based sources significantly impacts their bioavailability. LCn-3PUFA-rich microalgal oil offers a potential alternative for populations who do not consume oily fish, and nanoemulsions have the potential to increase LCn-3PUFA digestibility and bioavailability. The aims of this study were to produce stable algal oil-in-water nanoemulsions with ultrasonic technology to increase DHA digestibility, measured using an in vitro digestion model. A nanoemulsion of LCn-3PUFA algal oil was developed with 6% w/w emulsifiers: lecithin (LE) or an equal ratio of Tween 40 (3%) and lecithin (LTN) (3%), 50% w/w, algal oil and 44% w/w water using rotor-stator and ultrasound homogenization. The in vitro digestion experiments were conducted with a gastric and duodenal digestion model. The results showed the creation of nanoemulsions of LCn-3PUFA algal oils offers potentially significant increases in the bioavailability of DHA in the human body. The increase in digestibility can be attributed to the smaller particle size of the nanoemulsions, which allows for higher absorption in the digestive system. This showed that the creation of nanoemulsions of LCn-3PUFA algal oils offers a potentially significant increase in the bioavailability of DHA in the human body. The LE and LTN nanoemulsions had average droplet sizes of 0.340 ± 0.00 µm and 0.267 ± 0.00 µm, respectively, but the algal oil mix (sample created with same the components as the LTN nanoemulsion, hand mixed, not processed by rotor-stator and ultrasound homogenization) had an average droplet size of 73.6 ± 6.98 µm. The LTN algal oil nanoemulsion was stable in the gastric and duodenal phases without detectable destabilization; however, the LE nanoemulsion showed signs of oil phase separation in the gastric phase. Under the same conditions, the amount of DHA digested from the LTN nanoemulsion was 47.34 ± 3.14 mg/g, compared to 16.53 ± 0.45 mg/g from the algal oil mix, showing DHA digestibility from the LTN nanoemulsion was 2.86 times higher. The findings of this study contribute to the insight of in vitro DHA digestion under different conditions. The stability of the LTN nanoemulsion throughout digestion suggests it could be a promising delivery system for LCn-3PUFAs, such as DHA, in various food and pharmaceutical applications.

Effects of different decaffeination methods on caffeine contents, physicochemical, and sensory properties of coffee

Abstract Coffee consumption could provide various benefits for human health, but also could contribute to several health problems. The growing trend of coffee consumption has created a rising demand for decaffeinated coffee that is safe for consumers with low caffeine tolerance. Decaffeination process, however, can result in the alteration of several properties of coffee which affect overall coffee taste. This review discussed current decaffeination methods such as water decaffeination, solvent decaffeination, supercritical decaffeination, and biodecaffeination which includes their mechanisms, benefits, and drawbacks as well as their effect in the physicochemical and sensory characteristics of coffee. Solvent decaffeination has showed potential improvements in the future such as the incorporation of membrane and ultrasonic technology. In addition, the mathematical model for caffeine diffusion has been arranged according to Fick’s second law of diffusion, based upon spherical and rectangular coordinates with several assumptions. Further research should be aimed to maintain the properties of coffee after decaffeination process. Furthermore, utilizing new solvents that are safe and non-toxic will potentially be favorable research in the development of decaffeination methods in the future.

Fatigue Strength Improvement of Laser-Directed Energy Deposition 316L Stainless Steel with In Situ Ultrasonic Rolling by Preliminary Investigation.

In this study, to improve the fatigue strength of the LDED (laser-directed energy deposition) 316L stainless steel, an in situ ultrasonic rolling technology is developed to assist the laser-directed energy deposition process (LDED-UR). The microstructural characteristics and fatigue behavior are comprehensively discussed. The results show that the average size of pores of the LDED-UR alloy is about 10.2 μm, which is much smaller than that of the LDED alloy (34.1 μm). Meanwhile, the density of the LDED alloy is also enhanced from 98.26% to 99.27% via the in situ ultrasonic rolling. With the application of the in situ ultrasonic rolling, the grains are transformed into fully equiaxed grains, and their average grain size is greatly reduced from 84.56 μm to 26.93 μm. The fatigue limit of the LDED-UR alloy is increased by 29% from 210 MPa (LDED alloy) to 270 MPa, which can be ascribed to the decreased porosity and the fine grains. In particular, the crack initiation site of the LDED alloy is located at the surfaces, while it is nucleated from the sub-surface for the LDED-UR alloy. This is mainly attributed to the compression residual stress induced by the in situ ultrasonic rolling. This research offers a valuable understanding of the failure mechanisms in additively manufactured metals, guiding the development of effective strategies to improve their fatigue threshold under severe operating conditions.