bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficiency analysis of laser ultrasonic longitudinal wave detection based on the constraint effect
Authors: Guo Xing , Chen Youxing , Xun Yanqin , Wang Zhaoba , Li Ya 
Published: October 2024

Abstract
Laser ultrasound is a non-destructive inspection technique, but its application in internal defect detection and state characterization is limited by its weak body wave displacement induced by thermo-elastic mechanism. In this paper, the influence of the constraint layer on the directivity of laser induced ultrasonic force source and the excitation efficiency of longitudinal wave is analyzed by finite element modeling with transparent glass as the constraint layer. With the optimization of the parameters of the confinement layer, the longitudinal waves with energy comparable to that of the free surface ablation mechanism can be excited under the thermoelastic mechanism, which greatly improves the efficiency of the longitudinal wave of laser ultrasonic. Applying the above research results to the detection of internal defects, the imaging results of the internal defects are obvious and the location defects are accurate.
Study on the influence of typical turbulent flow field on the metering performance of cross four channel ultrasonic flowmeter
Authors: Zhou Chang , Xing Chao , Meng Tao , Wang Yiwen , Shi Huichao 
Published: October 2024

Abstract
In this paper, influence of typical turbulent flow field on a multi-channel ultrasonic flowmeter was studied. Experimental sample of the cross four-channel ultrasonic flowmeter were designed and processed, and CFD simulation models of flowmeter and right-handed spoiler, gate valve and velocity profile spoiler were established. Through simulation, the turbulent flow field behind typical spoilers such as right-handed spoiler, gate valve and velocity profile spoiler, and the influence of turbulent flow field on the metering performance of the cross four-channel ultrasonic flowmeter were studied. On this basis, the CFD simulation results and the real flow experiment results were compared and analyzed, and the reliability of the CFD simulation analysis results was verified, which provides the research basis for improving flowmeter performance.
Research on 3D Reconstruction of Paleontological Fossils Based on Photoacoustic Microscopy
Authors: Sun Mengyu , Zhong Yuanxin , Qin Zhengwang , Liu Zheng , Gao Chunming , Gong Yanli 
Published: October 2024

Abstract
The focus on three-dimensional morphological analysis of endogenous trace fossils has emerged as a prominent aspect in the study of palaeobiological fossils. Photoacoustic imaging technology, renowned for its deep penetration, high resolution and non-destructiveness, holds considerable promise in exploring fossil morphology. In this work, a solid-coupling-based photoacoustic microscopic imaging system was developed, leveraging this technology to investigate small-scale physical fossils. The proposed system enabled layered imaging of various fossil specimens, achieving a lateral resolution exceeds 35 μm and an axial resolution superior to 8.8815 μm. The three-dimensional reconstruction results were obtained through image processing algorithms. This system was proved to be efficient to imaging the small-scale physical fossils.
Simulation study of Rayleigh wave inspection of subsurface white etching crack in bearing rollers
Authors: Wu Chenchen , Zhu Qi , Su Zhan , Xu Duo , Zhang Haiyan 
Published: October 2024

Abstract
Rolling bearings are widely used in wind energy and electric vehicle industries. One of the premature failure mode due to the contact fatigue is White Etching Crack (WEC) in the subsurface. WEC occurs preferentially in the Hertzian contact region of bearings, preferentially around multi-phase inclusions containing aluminium, manganese, and sulfur. The formation process undergoes intense plastic deformation and recrystallization. Most of WECs are 100~300 μm below the contact surface in a butterfly shape. Its principal axis is 30°~50° to the rolling direction. Since the sample preparation is difficult, this simulation study enables to better understand the interaction between WEC and ultrasonic waves for a better measurement system design. Rayleigh surface wave penetrates to a depth of about an order of magnitude of one wavelength. Its energy is concentrated near the surface containing rich WEC information. The Rayleigh wave propagation process is first analyzed based on the grain scale model established. Then the immersion inspection of WEC is simulated based on the finite element method at 15 MHz in order to compromise between the detection accuracy and defect depth. Finally, by analyzing the time and frequency domain information of the scattered signals, the quantitative relationships between crack characteristics (depth, length and tilt angle) and those of Rayleigh waves (amplitude and attenuation) can be obtained. This study paves the way for the quantitatively characterization of WEC in bearing rollers with surface integrity evaluation possibility at early stage.
Ultrasonic evaluation of wire arc additively manufactured parts with heterogeneous microstructure
Authors: Cai X , Canturri C , Shandro R , Aishwarya  , Zhai W , Dupont B , Callejon A , Fan Z 
Published: October 2024

Abstract
In Wire Arc Additive Manufacturing (WAAM) components manufactured by gas metal arc welding strategy, periodically alternating patterns of fine- and coarse-grained microstructures develop along the building direction, depending on the temperature evolution. Ultrasonic non-destructive evaluation relies on the scattering of waves from defects. In the material microstructure, ultrasound waves are also scattered at the grain boundaries as grain noise. The work presents a study on the influence of heterogeneous microstructure in WAAM on defect detectability during ultrasonic inspections. The study used a 2D finite element model to simulate ultrasound wave propagation in the material microstructure represented by a surface element from electron backscatter diffraction scans. Side-drilled holes were introduced in the material as defects. Phased array was used to perform full matrix capture and obtain ultrasound image through total focusing method, with dynamic focusing capability to inspect the heterogeneous microstructure. The study analysed the defect echoes and noises using the signal-to-noise ratio (SNR) to assess its defect detectability. While defects were well detected, the SNR values differ by 10% for defects at various positions along the building and transverse directions in the heterogeneous microstructure.
Quality Evaluation of Argan Oil as a Food Product Using Ultrasonic Characterization
Authors: Ettahiri Mohamed , Hamine Adil , Ouacha El Houssaine , Mesbah Hicham , Tafkirte Mounir 
Published: October 2024

Abstract
Start This study focuses on evaluating the quality of food-grade argan oil, an essential component of Moroccan cuisine, using experimental ultrasonic characterization. Variations in ultrasonic velocity and attenuation with temperature were exploited as significant parameters for quality control of argan oil. The results reveal an inverse correlation between ultrasonic velocity and temperature, providing a unique model for the studied samples of argan oil. The measurements also show that the acoustic attenuation of argan oil decreases with temperature, while it increases with the volumetric fractions of sunflower oil added to argan oil. The data collected during this experimental study demonstrate that the velocity of the mixture of argan oil and sunflower oil increases with rising temperature. It was observed that both ultrasonic parameters of this mixture are challenging to detect by ultrasound. Ensuring the reproducibility of measurements under the same conditions, reference graphs are established to detect adulteration, especially when considering blends of argan oil with sunflower oil.
Adaptive total focusing method for ultrasonic full-matrix imaging of anisotropic CFRP laminates
Authors: Yu Zhenyang , Jin Haoran , Chen Jian 
Published: October 2024

Abstract
The application of total focusing method (TFM) for imaging of Carbon fiber reinforced plastics (CFRP) with ultrasonic phased array is particularly challenging due to the layered structure and anisotropy of CFRP. To improve the TFM imaging performance, the precise knowledge of complex ultrasonic paths in anisotropic CFRP laminates should be obtained for accurate calculation of time of flights (TOFs), which makes the inspection process complicated and time-consuming. In this work, an adaptive TFM is developed for full-matrix imaging of CFRP laminates using ultrasonic phased array. Based on the acquired full matrix data, the elastic constants, including C
11, C
22, C
55, and C
13, can be directly derived using TOFs of A-scan signals. Based on the measured elastic constants, group velocity profiles of quasi-pressure (QP) wave were then calculated for different stacking sequences, from which the TOFs were corrected. To verify the effectiveness of proposed method, simulations and experiments are demonstrated on the CFRP laminates with different stacking sequences. As a representative example, the delamination defects are showcased. Compared with isotropic TFM, the SNR of proposed method is increased by 10.2-18.0 dB. The simulated and experimental results agreed well with each other, indicating that the feasibility of proposed method in full matrix imaging of anisotropic CFRPs.
Subsurface defect detection of high-temperatured components with laser induced surface wave
Authors: Zeng YK , Qiu SY , Li FH , Chen J 
Published: October 2024

Abstract
Subsurface defects are detrimental to the safety and integrity of critical components in various fields, particularly for those used in high-temperature environments. For this reason, a reliable non-destructive evaluation (NDE) method for in-situ inspection of subsurface defects of high-temperatured components is highly desired. Laser ultrasonic technique offers a promising potential to accommodate the demands in virtue of non-contact generation and detection of ultrasonic waves. In this work, laser ultrasosnic inspection of subsurface defects in high-temperatured components is proposed, which exploits the modal conversion of surface longitudinal wave to Rayleigh wave. The modal conversion was firstly investigated with finite element simulation, from which the phenomenon of modal conversion can be readily identified. Thereafter, an experimental setup is built to verify the feasibility and effectiveness of proposed method. Notably, a delay-and-sum method based on a scanning procedure is conducted to coherently increase the detection sensitivity of subsurface defects, since the surface longitudinal wave rapidly vanishes with propagation distance., and the temperature-dependant velocity variation can be adaptively compensated. This work provides a viable route for in-situ inspection of subsurface defects in high-temperatured components where conventional ultrasonic method fails, and it would find potential applications in broad fields, such as coating quality evaluation in fabrication, bearing assessment under load, and in-situ monitoring for additive manufacturing.
Sparse-TFM imaging in frequency domain based on amplitude-squared parameter
Authors: Li Xiao , Luo Zhongbing , Shi Siqi , Jin Shijie 
Published: October 2024

Abstract
The total focusing method (TFM) implemented in time domain has high complexity, limiting its large-scale engineering applications. In contrast, the frequency-domain TFM based on phase shift migration (PSM) is helpful to improve imaging efficiency. On this basis, partial data can be abandoned for imaging to save computing costs and shorten processing time without reducing imaging quality. In this paper, an adaptive sparse-TFM in the frequency domain is proposed by selecting desired signals from full matrix capture (FMC) data. The amplitude-squared parameter for all the received signals corresponding to each transmitting element is taken as the relevant weight, and sparse arrays are constructed adaptively according to the descending order of numerical values. Simulated and experimental results indicate that the proposed method has stable imaging quality under different sparsity ratios, rapidly improving imaging efficiency with good resolution for defect detection.
The hydrodynamic noise suppression of the towed array by the combination of the flow and sustained release
Authors: Yong-Wei Liu , Rong-Jun Kang , Chun-ting Gu 
Published: October 2024

Abstract
This paper proposes a jet flow release method based on fish mucus to reduce the flow noise of the towed array. This method aims to alleviate the adverse effects of turbulent fluctuating pressure on the self-noise of a towed array at high speeds and address the problem of target signal masking caused by flow noise. A circular jet nozzle is installed at the front end of the towed array to spray mucus backward, reducing the turbulent fluctuating pressure on the surface of the towed array and improving the signal-to-noise ratio. Large eddy simulation using Fluent and finite element calculation of the acoustic field using Actran are employed to obtain flow and acoustic field results, respectively. The research findings demonstrate that after spraying mucus through the jet nozzle, the model’s viscous drag is reduced, and the excitation on the surface is significantly decreased, leading to a noticeable reduction in the self-noise sound pressure level in the frequency range of 150–2000 Hz.
Iterative processing of the noise coherence matrix to determine the acoustic properties of the water area
Authors: Dmitriev K V 
Published: October 2024

Abstract
An expression is given for the coherence matrix of the acoustic field produced by random sources in an inhomogeneous medium in the Born approximation. An iterative algorithm is proposed to determine the wave number inside the inhomogeneity based on this expression. The reconstruction results are analyzed for the cases of precise input data, data with interference, and incomplete data.
Self correction technique for amplitude and phase errors of underwater acoustic arrays based on variable decibel Bayesian inference
Authors: Zhao Ounan , Wang Qing , Chen Xiaosen , Wang Fangyong , Du Shuanping 
Published: October 2024

Abstract
Direction of arrival (DOA) estimation of underwater targets is an important research direction in the field of underwater acoustic array signal processing. Due to factors such as assembly errors and component aging, amplitude and phase errors between each channel of the array are common, resulting in distortion of the array flow pattern matrix. At the same time, the non-uniform distribution of noise intensity at the positions of each array element further increases the difficulty of DOA for underwater targets. Based on the characteristics of sparse spatial distribution of underwater targets, this paper uses the flexibility of hyperparametric modeling to construct an array observation signal graph model. On this basis, the effects of amplitude and phase errors and non-uniform noise on the array model are added, and a comprehensive observation model with clear distribution types of amplitude and phase errors, signals, and noise is established. The variational Bayesian inference theory is used to obtain closed solutions of various variables and parameters, so as to achieve joint estimation of target azimuth and error parameters. Simulation results and sea trial data processing results show that the algorithm can achieve amplitude and phase error self correction while completing DOA estimation in the absence of prior information on the number of sources.
Study on high-order-mode oscillation and migration characteristics of single bubble in the ultrasonic field
Authors: Huang Xiao , Niu Guang-Yun , Ren Chun-Zhu , Luo Xiao 
Published: October 2024

Abstract
Investigating the motion characteristics of cavitation bubbles in an ultrasonic field is important for industries such as ultrasonic cleaning and ultrasonic therapy. This paper investigated the oscillation and migration characteristics of a single cavitation bubble in a 20 kHz ultrasonic field. Peristaltic pump syringe injection tests were performed at different locations in a 20 kHz ultrasonic field, and a high-speed camera was used to observe the bubble motion characteristics. The bubble was found to resonate with the ultrasonic waves at a higher order mode, changing from spherical shape to honeycomb and golf ball shapes. Also, we found that the ultrasonic waves may prevent the buoyancy of the bubble. Through revealing the motion characteristics of the bubble in the ultrasonic field, we may control the bubble motion by ultrasonic, and strengthen the bubble cavitation effect.
Efficient numerical simulation method for nonlinear guided wave in frequency domain
Authors: Sun Chaoyu , Song Ailing , Xiang Yanxun 
Published: October 2024

Abstract
Nonlinear ultrasonic guided wave has attracted increasing attention for its ultra-sensitive to detect the incipient damages in service material by analyzing the amplitude of second harmonic wave. However, the mainstream method of simulating the second harmonic generation (SHG) in nonlinear material is using finite element method with time-domain solver, which is extremely time-consuming and can hardly simulate the huge and complex structures. In this paper, we propose a flexible finite element method based on frequency solver to simulate the SHG. The primary wave field, the second harmonic wave field and the static component field are separately set. This method is realized in Comsol Multiphysics software, the case of the SHG in plate indicates that the calculation efficiency has been significantly improved in compare with the time domain solver, whereas the results of time-domain solver and frequency domain solver have good agreement with each other. This method can be easily applied in the SHG analysis in huge and complex structures. Moreover, the primary wave field, the second harmonic wave field and the static component field can be respectively presented in the post-processing to help provide more information about physical insight of SHG.
On the cutoff, reappearance, and persistence of subsonic leaky A0 Lamb waves
Authors: Viggen E M , Arnestad H K 
Published: October 2024

Abstract

Subsonic leaky A0 Lamb waves, whose phase speeds are lower than the fluid’s sound speed, exhibit several peculiar behaviours. In this work, we investigate three such behaviours: Cutoff, where the A0 branch cuts off at some point in the subsonic domain, reappearance, where the cut-off A0 branch reappears at lower frequencies, and persistence, where the A0 branch is never cut off at all. From the literature, we take the case of a 1 mm thick aluminium plate immersed in air of varying density. We then analyse its exact leaky A0 wave solutions by means of a sound radiation model that takes energy conservation into account. This analysis explains these peculiar behaviours by connecting them with the conditions that allow sound-radiating subsonic leaky A0 Lamb waves.
Influence of polyethylene pipe butt fusion welding in ultrasonic non-destructive testing
Authors: An Bingwen , Li Ziqi , Li Feiran , Fang Xuefeng , Jiang Xueping , Leng Tao , Wu Xianmei 
Published: October 2024

Abstract
Butt fusion welding is a commonly used manufacturing method for polyethylene pipes. To investigate the influence of butt fusion welding on oblique ultrasonic wave in ultrasonic non-destructive testing, a numerical simulation model was established for polyethylene pipe with welding joints. Wave propagation in the polyethylene pipe was analysed, which showed that there exist longitudinal and shear waves propagating and their mode conversion. Detection signals of pipes with different defects and different acoustic attenuations were calculated. The special structure of welding joint was then modelled. Results show that the signal response declines with acoustic attenuation coefficient. Butt welding joints, especially the inner joints, would affect waves propagation. Finally, the welding process of polyethylene pipes was also simulated. The influence of cooling time was discussed, which indicated that insufficient cooling time would cause thermal residual stress and then alter the ultrasonic signal.
An exact analytical solution for coupled vibration analysis of a piezoelectric resonator
Authors: Ding Wenxiang , Li Liangtian , Wei Sheng , Bao Danyang , Zhou Hui , Sun Guodong 
Published: October 2024

Abstract
Piezoelectric resonators are widely used as the active components in devices such as sensors, actuators, communication filters, and micro/nano-electro-mechanical systems (MEMS / NEMS). Due to the piezoelectric effect, Poisson’s ratio, and its finite dimension, the thickness and lateral vibration modes in a piezoelectric resonator are inevitably coupled. In this paper, an exact analytical model for coupled vibration analysis of a piezoceramic disk is developed based on a new superstition method. The free vibrations are decomposed into thickness and lateral directions in a new form of Fourier-Bessel series and then they are superimposed to satisfy the boundary conditions. To verify the validity of the analytical model proposed here, numerical simulations are performed using COMSOL Multiphysics. An excellent agreement is observed. This analytical model can be applied to the design and optimization of piezoelectric devices.
Enhancing Alaskan wildfire prediction and carbon flux estimation: a two-stage deep learning approach within a process-based model
Authors: Seo Hocheol , Kim Yeonjoo 
Published: October 2024

Abstract
Wildfires in boreal forests release substantial amounts of carbon into the atmosphere. However, current land-surface models are limited in their representation of fire processes, including their ignition and spread. This study thus developed FireDL, a novel data-driven machine-learning model for the prediction of natural wildfires, and combined it with a land-surface model to better understand the impact of fire on carbon fluxes. FireDL has a two-stage deep learning structure that sequentially combines a long short-term memory (LSTM) algorithm and an artificial neural network (ANN). Preliminary random forest analysis identified fire duration as an important factor in predicting the burned area. Thus, in FireDL, the LSTM algorithm was employed to predict fire occurrence and duration, utilizing lightning, vegetation, and climate datasets. Subsequently, the ANN predicted the total burned area using the LTSM-derived fire duration predictions and climate datasets as input. FireDL produced a robust performance in predicting large fires (>10 000 ha), achieving a correlation coefficient of 0.72. The daily-scaled burned area predictions derived from FireDL were integrated into the Community Land Model version 5—Biogeochemistry (CLM5-BGC) to produce CLM5-BGC-FireDL. This integration considerably improved carbon emission estimations. Notably, the total net ecosystem exchange (NEE) estimated using CLM5-BGC-FireDL in 2019, the year with the highest recorded burned area during our study, was twice that estimated using the standard CLM5-BGC. Discrepancies in the NEE can significantly influence atmospheric CO2 levels, highlighting the importance of our fire prediction model in forecasting the burned area and carbon emissions. The use of FireDL with future climate scenarios is thus anticipated to yield valuable insights into ecosystem management and climate change mitigation strategies.