12,258 results on '"SPEED of sound"'
Search Results
2. An Underwater Velocity-Independent DOA Estimation Method Based on Cascaded Neural Network.
- Author
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Yuan, Sihan, Ning, Gengxin, and Lin, Yushen
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SPEED of sound , *BLIND source separation , *CASCADE connections , *VELOCITY - Abstract
The underwater environment introduces uncertainty into the acoustic velocity, which affects the performance of traditional direction of arrival (DOA) estimation methods. This research proposes a cascaded neural network based underwater DOA estimate approach to address this issue. In this method, the cascade neural network is composed of a velocity regressor and a velocity classifier. To determine the estimated value of acoustic velocity, the velocity classifier first breaks down the input data into distinct velocity domains. It then regulates the velocity regression process. Then, the array steering matrix predicted by the blind source separation algorithm is utilized to determine the angle, and the acoustic velocity is modiffed by the cascaded neural network. Eventually, it is possible to derive the DOA estimation value under the calculated acoustic velocity. The suggested method has a high estimation accuracy especially when the acousitc velocity is unknown, as shown by the simulation results. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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3. Acoustic Wave Velocities in Bridge Steels and the Effects on Ultrasonic Testing.
- Author
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Washer, Glenn, Agbede, Joshua, Yadav, Kalpana, Connor, Robert, and Turnbull, Ryan
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SPEED of sound , *HEAD waves , *SHEAR waves , *MANUFACTURING processes , *ULTRASONIC welding - Abstract
Ultrasonic testing is utilized to ensure weld quality during the fabrication of steel bridges by identifying discontinuities that are classified as either acceptable or rejectable. The classification of a discontinuity can be affected by differences in the acoustic properties of the material under test and the reference standard used for calibration. Differences in wave velocity affect the refracted angle and amplitude of refracted shear waves. As a result, indications can be missed or incorrectly classified, or incorrectly located in the material. The objective of this research study was to characterize the acoustic wave velocities in a sample of contemporary steels to better understand the range over which velocities may vary for common steels. To address this objective, a series of velocity measurements have been conducted for shear waves propagating through different directions in steel plates of different strengths and reported manufacturing processes. The study also examines the loss of signal amplitude that results from changes in the refracted angle of shear waves used for the inspection of welds. Beam splitting that may occur in anisotropic materials and the potential impact on signal amplitudes is also presented. It was shown in the research that relatively small differences in velocity between the material under test and the reference standard cause a loss of sensitivity of the test. Data presented in the paper documents wave velocity and anisotropic ratios for a population of contemporary bridge steels used for the fabrication of steel bridges and an assessment of how velocity differences affect the amplitude of reflected shear waves. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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4. Integration of attention mechanism and CNN-BiGRU for TDOA/FDOA collaborative mobile underwater multi-scene localization algorithm.
- Author
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Peng, Duo, Liu, Ming Shuo, and Xie, Kun
- Subjects
CONVOLUTIONAL neural networks ,SPEED of sound ,OCEAN waves ,RADIATION sources ,LEAST squares - Abstract
The aim of this study is to address the issue of TDOA/FDOA measurement accuracy in complex underwater environments, which is affected by multipath effects and variations in water sound velocity induced by the challenging nature of the underwater environment. To this end, a novel cooperative localisation algorithm has been developed, integrating the attention mechanism and convolutional neural network-bidirectional gated recurrent unit (CNN-BiGRU) with TDOA/FDOA and two-step weighted least squares (ImTSWLS). This algorithm is designed to enhance the accuracy of TDOA/FDOA measurements in complex underwater environments. The algorithm initially makes use of the considerable capacity of a convolutional neural network (CNN) to extract profound spatial and frequency domain characteristics from multimodal data. These features are of paramount importance for the characterisation of underwater signal propagation, particularly in complex environments. Subsequently, through the use of a bidirectional gated recurrent unit (BiGRU), the algorithm is able to effectively capture long-term dependencies in time series data. This enables a more comprehensive analysis and understanding of the changing pattern of signals over time. Furthermore, the incorporation of an attention mechanism within the algorithm enables the model to focus more on the signal features that have a significant impact on localisation, while simultaneously suppressing the interference of extraneous information. This further enhances the efficiency of identifying and utilising the key signal features. ImTSWLS is employed to resolve the position and velocity data following the acquisition of the predicted TDOA/FDOA, thereby enabling the accurate estimation of the position and velocity of the mobile radiation source. The algorithm was subjected to a series of tests in a variety of simulated underwater environments, including different sea states, target motion speeds and base station configurations. The experimental results demonstrate that the algorithm exhibits a deviation of only 2.88 m/s in velocity estimation and 2.58 m in position estimation when the noise level is 20 dB. The algorithm presented in this paper demonstrates superior performance in both position and velocity estimation compared to other algorithms. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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5. Study of Anisotropic Compact Star Model in Modified Gravity Using Finch–Skea Geometry.
- Author
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Shahzad, M. R., Amjad, M., Essa, Y. M. Abo, El-Rashidy, K., Rasheed, Faisal, Hakami, Khalil Hadi, Emadifar, Homan, and Malik, Adnan
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ANALYTIC geometry , *SPEED of sound , *REDSHIFT , *GRAVITY , *EQUATIONS - Abstract
In this work, we construct a new model of compact stars in the presence of anisotropic matter in the Rastall theory of gravity. For this, we considered the anisotropic matter content when formulating the Rastall field equations. Secondly, the Tolman–Oppenheimer–Volkoff (TOV) equation in the context of Rastall theory is formulated. We apply the Finch–Skea ansatz in the static and spherically symmetric geometry to obtain the analytic solution of the derived field equations in the Rastall theory of gravity. We match the internal solution to the corresponding external Schwarzschild space‐time in order to determine the values of the unknown constants involved in the Rastall field equations due to the Finch–Skea ansatz. The resulting model is applied to a few prominent compact stars in order to verify its physical viability. Energy conditions, the TOV equation, stability analysis via sound speeds (radial and transverse in this case), equation of state parameters, mass function, compactness, and surface redshift are some of the analytical expressions that are examined in this inquiry. In order to verify the physical acceptance of the obtained results, we provided a graphical analysis of some necessary analytical expressions. Also, the numerical values of some physical parameters are calculated and are presented in the tabular form to observe the Buchdahl limit and some other important criterion. We note that our model is well consistent with the physical requirements. [ABSTRACT FROM AUTHOR] more...
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- 2024
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6. Resonance-State Temperature Compensation Method for Ultrasonic Resonance Wind Speed and Direction Sensors.
- Author
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Zeng, Xiangbao, Yuan, Yupeng, Jiang, Zhuoya, Wang, Lu, Long, Shuai, and Yu, Hua
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WIND speed measurement , *SPEED of sound , *TEMPERATURE sensors , *RESONANCE , *ULTRASONICS - Abstract
To achieve high-precision wind speed and direction measurements in complex environments, a resonance-state temperature compensation method is proposed based on an ultrasonic resonance principle. This method effectively addresses the issue of sound velocity compensation errors caused by the temperature difference between the internal and external environments when using an internal temperature sensor for temperature compensation. By utilizing an adaptive resonance-state tracking model, the resonance frequency shift issues under varying conditions such as altitude, pressure, and temperature are mitigated. This approach ensures that the resonance frequency is strongly correlated with temperature, enabling temperature compensation through resonance frequency alone, without the need for a temperature sensor. The experimental results indicate that the resonance frequency variation rate with temperature for the resonance-state temperature-compensated ultrasonic resonance wind speed and direction sensor is approximately 0.08 kHz/°C. The wind speed measurement accuracy is ±0.3 m/s (≤15 m/s)/±2.3% (15 m/s~50 m/s), which is superior to the measurement accuracy of traditional ultrasonic wind speed and direction sensors (±0.5 m/s (≤15 m/s)/±4% (15 m/s~50 m/s)). The consistency of wind speed measurement is ≤±0.3%, representing an improvement of approximately 3% compared to ultrasonic resonance wind speed and direction sensors without resonance-state temperature compensation. [ABSTRACT FROM AUTHOR] more...
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- 2024
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7. Sound Speed Prediction Equations for Seafloor Sediments in Offshore Area Southeast of Hainan Island.
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Tian, Yuhang, Lu, Licheng, Zhai, Yufeng, Zhang, Yingwei, Chen, Zhong, Yan, Wen, and Wan, Kuiyuan
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GRAIN size ,SENSITIVITY analysis ,STATISTICAL correlation ,SEDIMENTS ,EQUATIONS ,SPEED of sound - Abstract
In this study, single- and double-parameter empirical equations were produced, and the influences of physical properties on sound speed were assessed, based on the measured data of seafloor sediments obtained in an area near southeastern Hainan Island. The correlation coefficients of the single-parameter empirical equations were found to be greater than 0.65, while those of the double-parameter empirical equations were found to be greater than 0.72, indicating that the double-parameter empirical equations have an advantage in predicting sound speed. According to the sensitivity analysis, mean grain size is the best predictor for sediment sound speed. Furthermore, the empirical equations constructed in this study are a significant addition to sound speed prediction equations and have important application potential in predicting sound speed in the studied area near southeastern Hainan Island. [ABSTRACT FROM AUTHOR] more...
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- 2024
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8. Unveiling the spatial-temporal dynamics: Diffusion-based learning of conditional distribution for range-dependent ocean sound speed field forecasting.
- Author
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Gao, Ce, Cheng, Lei, Zhang, Ting, and Li, Jianlong
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MACHINE learning , *SPEED of sound , *KRIGING , *UNDERWATER acoustic communication , *ACOUSTIC field , *RECURRENT neural networks - Abstract
Environment-aware underwater acoustic detection and communications demand precise forecasting of the sound speed field (SSF) both temporally and spatially. Toward this goal, recent machine learning models, such as recurrent neural networks and Gaussian process regressions, have outperformed classical autoregressive models. However, from the unified theoretical perspective of conditional distribution learning, there is still significant room for improvement, as existing works have not fully learned the conditional distribution of future SSFs given past SSFs. To address these limitations, in this paper, we leverage the use of diffusion models, the foundation of recent successful deep generative models, such as DALL-E 2 and SORA, to learn the conditional distribution even under limited training data, through careful neural architecture and training strategy design. Our experiments, conducted on real-life South China Sea datasets, confirm that our proposed model outperforms the state-of-the-art baselines in forecasting range-dependent SSFs and the associated underwater transmission losses. Additionally, our model provides reliable confidence intervals that quantify the uncertainties of predictions. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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9. A baseline decomposition ultra-short baseline localization algorithm for arbitrary array structures.
- Author
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Da, Lianglong, Liu, Baoheng, Zou, Sichen, and Zhang, Xiaochuan
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SPEED of sound , *LEAST squares , *MARINE engineering , *SYSTEMS theory , *COORDINATE transformations - Abstract
With the rapid development of the marine economy, hydroacoustic positioning technology plays an increasingly important role in marine engineering. The ultra-short baseline (USBL) hydroacoustic positioning system has the advantages of small size, simple operation, and flexible use, and has been widely used. Aiming at the existing USBL acoustic positioning algorithm with low positioning accuracy and complex calculation, a baseline decomposition localization algorithm with arbitrary array structure is proposed. The algorithm is based on the theory of coordinate system transformation, establishes positioning observation equations for each baseline in the base array, and adopts the least squares method to obtain positioning results by selecting different combinations of baselines. The systematic errors of different positioning models themselves are simulated, and then the effects of the three parameter errors, namely, time delay, element coordinates, and sound speed, on the positioning results are analyzed, respectively. Finally, the simulation results and sea trial data show that, compared with the existing algorithms, this algorithm not only simplifies the complicated computation process, but also improves the positioning accuracy and robustness, and has a better application effect. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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10. A Chebyshev collocation method for directly solving two-dimensional ocean acoustic propagation in linearly varying seabed.
- Author
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Ma, Xian, Wang, Yongxian, Zhu, Xiaoqian, Zhou, Xiaolan, Tu, Houwang, Xu, Guojun, Gao, Dongbao, and Zhou, Hefeng
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SPEED of sound , *INHOMOGENEOUS materials , *ACOUSTIC field , *ACOUSTIC models , *APPROXIMATION error - Abstract
It is one of the most concerning problems in hydroacoustics to find a method that can calculate the acoustic propagation accurately and adapt to the variation of the seabed. Currently, the one-dimensional spectral method has been employed to address the simplified ocean acoustic propagation model successfully. However, due to the model's application limitations and approximation error, it poses challenges when attempting to solve real-world ocean acoustic fields. Hence, there is a crucial need to develop a direct solution method for the two-dimensional Helmholtz equation of ocean acoustic propagation, without relying on a simplified model. In previous work, we achieved successful solutions for the two-dimensional Helmholtz equation within a rectangular domain, utilizing a collocation-type spectral method. Taking into account the fluctuations in the actual seabed, we introduce a Chebyshev collocation spectral method to directly tackle the two-dimensional ocean acoustic propagation problem, which could solve the case of a seabed with linear variation, sound velocity variation and inhomogeneous medium situation. After comparative verification, the calculation result of the two-dimensional spectral method is more accurate than traditional mature models such as Kraken and COUPLE. By eliminating model constraints and enlarging the solution range, this spectral method holds immense potential in real marine environments. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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11. A Polyvinyl Alcohol (PVA)-Based Phantom for Prostate Cancer Detection Using Multiparametric Ultrasound: A Validation Study.
- Author
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Jawli, Adel, Nabi, Ghulam, and Huang, Zhihong
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SONAR , *DOPPLER ultrasonography , *POLYVINYL alcohol , *YOUNG'S modulus , *SPEED of sound - Abstract
Multiparametric ultrasound (mpUS) enhances prostate cancer (PCa) diagnosis by using multiple imaging modalities. Tissue-mimicking materials (TMM) phantoms, favoured over animal models for ethical and consistency reasons, were created using polyvinyl alcohol (PVA) with varying molecular weights (Mw). Methods: Four PVA samples, varying in Mw with constant concertation, were mixed with glycerol, silicon carbide (SiC), and aluminium oxide (Al2O3). Phantoms with varying depth and inclusion sizes were created and tested using shear-wave elastography (SWE). An mpUS phantom was developed to mimic prostate tissue, including isoechoic and hypoechoic inclusions and vessels. The phantom was scanned using supersonic ultrasound, strain elastography, and Doppler ultrasound. Validation was performed using radical prostatectomy data and shear-wave elastography. Results: The acoustic properties varied with enhancers like glycerol and Al2O3. Low Mw PVA samples had a speed of sound ranging from 1547.50 ± 2 to 1553.70 ± 2.2 m/s and attenuation of 0.61 ± 0.062 to 0.63 ± 0.05 dB/cm/MHz. High Mw PVA samples ranged from 1555 ± 2.82 to 1566 ± 4.5 m/s and 0.71 ± 0.02 to 0.73 ± 0.046 dB/cm/MHz. Young's modulus ranged from 11 ± 2 to 82.3 ± 0.5 kPa across 1 to 10 freeze-thaw cycles. Inclusion size, depth, and interaction statistically affect the SWE measurements with p-value = 0.056327, p-value = 8.0039 × 10−8, and p-value = 0.057089, respectively. SWE showed isoechoic inclusions, prostate tissue, and surrounding tissue only. The Doppler velocity was measured in three different inner diameters. Conclusion: PVA mixed with enhancer materials creates an mpUS phantom with properties that mimic normal and abnormal prostate tissue, blood vessels, and soft tissue, facilitating advanced diagnostic training and validation. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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12. Healing Environment in Pediatric Cancer Centers by Utilizing Positive Distractions.
- Author
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Alhsainat, Aseel and Günçe, Kağan
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SPEED of sound , *EMPLOYEE benefits , *CHILDHOOD cancer , *INTERIOR decoration , *AMBIENCE (Environment) - Abstract
In recent years, a broader perspective has viewed the use of therapeutic environments in healthcare, transforming the hospital's environment into an energizing atmosphere that benefits both employees and patients. Scientists found that exposure to natural elements like nature scenes, sunlight, art, calming colors, and soothing sounds significantly sped up healing and created a more relaxed hospital environment. This research emphasized the importance of healthcare settings' interior design in promoting patient well-being through beneficial distractions. The motivation for this investigation came from the need to develop an understanding of positive distractions in the cancer care environment and showed how this understanding could be used to enhance the space experience to promote health and well-being. This research adopted a mixed-methods approach. First, a qualitative method using a critical review of the literature was used to effectively present, analyze, and synthesize literature from diverse sources, followed by a quasi-experimental research method. This research is intended to focus on the attributes of positive distraction as one of the psychosocially and psychologically supportive healthcare design aspects that evoke positive feelings in children's cancer center experiences. [ABSTRACT FROM AUTHOR] more...
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- 2024
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13. Experimental Investigation of Steel-Borne Acoustic Pulses for Fault Pinpointing in Pipe-Type Cable Systems: A Scaled-Down Model Approach.
- Author
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Moutassem, Zaki, Li, Gang, and Zhu, Weidong
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FAULT location (Engineering) , *CARBON steel , *SPEED of sound , *THERMAL expansion , *POWER transmission - Abstract
Pipe-type cable systems, including high-pressure fluid-filled (HPFF) and high-pressure gas-filled cables, are widely used for underground high-voltage transmission. These systems consist of insulated conductor cables within steel pipes, filled with pressurized fluids or gases for insulation and cooling. Despite their reliability, faults can occur due to insulation degradation, thermal expansion, and environmental factors. As many circuits exceed their 40-year design life, efficient fault localization becomes crucial. Fault location involves prelocation and pinpointing. Therefore, a novel pinpointing approach for pipe-type cable systems is proposed, utilizing accelerometers mounted on a steel pipe to capture fault-induced acoustic signals and employing the time difference of arrival method to accurately pinpoint the location of the fault. The experimental investigations utilized a scaled-down HPFF pipe-type cable system setup, featuring a carbon steel pipe, high-frequency accelerometers, and both mechanical and capacitive discharge methods for generating acoustic pulses. The tests evaluated the propagation velocity, attenuation, and pinpointing accuracy with the pipe in various embedment conditions. The experimental results demonstrated accurate fault pinpointing in the centimeter range, even when the pipe was fully embedded, with the acoustic pulse velocities aligning closely with the theoretical values. These experimental investigation findings highlight the potential of this novel acoustic pinpointing technique to improve fault localization in underground systems, enhance grid reliability, and reduce outage duration. Further research is recommended to validate this approach in full-scale systems. [ABSTRACT FROM AUTHOR] more...
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- 2024
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14. Study and Analysis of the Thunder Source Location Error Based on Acoustic Ray-Tracing.
- Author
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Guo, Jinyuan, Wang, Caixia, Xu, Jia, Jia, Song, Yang, Hui, Sun, Zhuling, and Wang, Xiaobao
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SPEED of sound , *EARTH temperature , *TEMPERATURE distribution , *SOUND waves , *ERROR analysis in mathematics , *ACOUSTIC wave propagation - Abstract
Error analysis and estimation of thunder source location results is a prerequisite for obtaining accurate location results of thunder sources, which is of great significance for a deeper understanding of the physical process of lightning channel discharges. Most of the thunder source location algorithms are based on the simplified model of the straight-line propagation of acoustic waves to determine the location of the thunder source; however, the acoustic wave is affected by the inhomogeneity of the atmosphere medium in the propagation process and its acoustic ray will be bent. Temperature and humidity are the main factors affecting the vertical distribution of the velocity of sound in the atmosphere, therefore, it is necessary to study the changes in location errors under the models of uniform vertical distribution of temperature only and uniform vertical distribution of humidity only. This paper focuses on the theory of acoustic ray-tracing in neglecting the presence of the wind and the acoustic attenuation and the theoretical derivation of the location error of thunder source inversion for the three models is carried out by using MATLAB R2019b programming. Then, simulation analysis and comparative study on the variation law of thunder source location error with the height of the source, ground temperature, ground humidity, and array position under the three models are carried out. The results of the study show that the maximum location error can be obtained from the straight-line propagation model, the location error obtained from the model of uniform vertical distribution of temperature only is the second, and the location error obtained from the model of uniform vertical distribution of humidity only is the least and can be negligible compared to the first two models. In the trend of error variation, the variation of location error with temperature and humidity is relatively flat in the first two models; however, the variation of location error with the height of the thunder source is more drastic, which can be more than 80%. The location error obtained from the array inversion closer to the thunder source increases linearly with the height of the thunder source, the location error obtained from the more distant array inversion shows a fast-decreasing trend at the height of the thunder source from 500 to 3500 m, and a flat trend above 3500 m. The location error varies relatively smoothly with the height of the thunder source, the ground temperature, and the ground humidity in the model of uniform vertical distribution of humidity only. In addition, the position of the array also has an important effect on lightning location. The further the horizontal distance from the source, the greater the location error will be obtained in the first two models, and when the thunder source is at a low height and detected at a long distance, the location error will be very large, so relevant data should be modified in actual observation. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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15. An internal variable model of macroscopic twin boundary dynamics.
- Author
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Berezovski, Arkadi
- Subjects
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TWIN boundaries , *CONTINUUM mechanics , *VELOCITY , *SPEED of sound - Abstract
Depending on whether the experiments are quasi-static or fast dynamics, the measured twin boundary velocity values range from zero to the material's sound speed. The twin boundary velocity is not yet predicted theoretically in the continuum mechanics framework. The extension of continual description is provided in the paper by means of internal variables. It is shown that a diffusional slow motion of twin boundaries can be represented using a single internal variable. The dual internal variable technique is employed for the description of the fast dynamics of twin boundaries. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
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16. Cross-Layer Routing Protocol Based on Channel Quality for Underwater Acoustic Communication Networks.
- Author
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He, Jinghua, Tian, Jie, Pu, Zhanqing, Wang, Wei, and Huang, Haining
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UNDERWATER acoustic communication ,MACHINE learning ,TELECOMMUNICATION systems ,BIT error rate ,SPEED of sound - Abstract
Due to the physical characteristics of acoustic channels, the performance of underwater acoustic communication networks (UACNs) is more susceptible to the impacts of multipath and Doppler effects. Channel quality can serve as a measure of the reliability of underwater communication links. A cross-layer routing protocol based on channel quality (CLCQ) is proposed to improve the overall network performance and resource utilization. First, the BELLHOP ray model is used to calculate the channel impulse response combined with the winter sound speed profile data of a specific sea area. Then, the channel impulse response is integrated into the communication system to evaluate the channel quality between nodes based on the bit error rate (BER). Finally, during the selection of the next hop node, a reinforcement learning algorithm is employed to facilitate cross-layer interaction within the protocol stack. The optimal relay node is determined by the channel quality index (BER) from the physical layer, the buffer state from the data link layer, and the node residual energy. To enhance the algorithm's convergence speed, a forwarding candidate set selection method is proposed which takes into account node depth, residual energy, and buffer state. Simulation results show that the packet delivery rate (PDR) of the CLCQ is significantly higher than that of Q-Learning-Based Energy-Efficient and Lifetime-Extended Adaptive Routing (QELAR) and Geographic and Opportunistic Routing (GEDAR). [ABSTRACT FROM AUTHOR] more...
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- 2024
- Full Text
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17. Data-Driven Analysis of Ocean Fronts' Impact on Acoustic Propagation: Process Understanding and Machine Learning Applications, Focusing on the Kuroshio Extension Front.
- Author
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Xu, Weishuai, Zhang, Lei, Li, Ming, Ma, Xiaodong, and Li, Maolin
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FRONTS (Meteorology) ,SPEED of sound ,UNDERWATER acoustic communication ,UNDERWATER acoustics ,MACHINE learning - Abstract
Ocean fronts, widespread across the global ocean, cause abrupt shifts in physical properties such as temperature, salinity, and sound speed, significantly affecting underwater acoustic communication and detection. While past research has concentrated on qualitative analysis and small-scale research on ocean front sections, a comprehensive analysis of ocean fronts' characteristics and their impact on underwater acoustics is lacking. This study employs high-resolution reanalysis data and in situ observations to accurately identify ocean fronts, sound speed structures, and acoustic propagation features from over six hundred thousand Kuroshio Extension Front (KEF) sections. Utilizing marine big data statistics and machine learning evaluation metrics such as out-of-bag (OOB) error and Shapley values, this study quantitatively assesses the variations in sound speed structures across the KEF and their effects on acoustic propagation shifts. This study's key findings reveal that differences in sound speed structure are significantly correlated with KEF strength, with the channel axis depth and conjugate depth increasing with front strength, while the thermocline intensity and depth excess decrease. Acoustic propagation features in the KEF environment exhibit notable seasonal variations. [ABSTRACT FROM AUTHOR] more...
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- 2024
- Full Text
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18. A Laterally Excited Bulk Acoustic Wave Resonator Based on LiNbO 3 with Arc-Shaped Electrodes.
- Author
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Liu, Jieyu, Liu, Wenjuan, Wen, Zhiwei, Zeng, Min, and Sun, Chengliang
- Subjects
ACOUSTIC resonators ,INTERDIGITAL transducers ,SPEED of sound ,MODE shapes ,PIEZOELECTRIC materials - Abstract
High frequency and large bandwidth are growing trends in communication radio-frequency devices. The LiNbO
3 thin film material is expected to become the preferred piezoelectric material for high coupling resonators in the 5G frequency band due to its ultra-high piezoelectric coefficient and low loss characteristics. The main mode of laterally excited bulk acoustic wave resonators (XBAR) have an ultra-high sound velocity, which enables high-frequency applications. However, the interference of spurious modes is one of the main reasons hindering the widespread application of XBAR. In this paper, a Z-cut LiNbO3 thin film-based XBAR with arc-shaped electrodes is presented. We investigate the electric field distribution of the XBAR, while the irregular boundary of the arc-shaped electrodes affects the electric field between the existing interdigital transducers (IDTs). The mode shapes and impedance response of the XBAR with arc-shaped electrodes and the XBARs with traditional IDTs are compared in this work. The fabricated XBAR on a 350 nm Z-cut LiNbO3 thin film with arc-shaped electrodes operating at over 5 GHz achieves a high effective electromechanical coupling coefficient of 29.8% and the spurious modes are well suppressed. This work promotes an XBAR with an optimized electrode design to further achieve the desired performance. [ABSTRACT FROM AUTHOR] more...- Published
- 2024
- Full Text
- View/download PDF
19. Fundamental influence of irreversible stress–strain properties in solids on the validity of the ramp loading method.
- Author
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Shen, Jingxiang and Kang, Wei
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PROPERTIES of matter ,PHASE transitions ,LONGITUDINAL waves ,MOLECULAR dynamics ,SPEED of sound - Abstract
The widely used quasi-isentropic ramp loading technique relies heavily on back-calculation methods that convert the measured free-surface velocity profiles to the stress–density states inside the compressed sample. Existing back-calculation methods are based on one-dimensional isentropic hydrodynamic equations, which assume a well-defined functional relationship P(ρ) between the longitudinal stress and density throughout the entire flow field. However, this kind of idealized stress–density relation does not hold in general, because of the complexities introduced by structural phase transitions and/or elastic–plastic response. How and to what extent these standard back-calculation methods may be affected by such inherent complexities is still an unsettled question. Here, we present a close examination using large-scale molecular dynamics (MD) simulations that include the detailed physics of the irreversibly compressed solid samples. We back-calculate the stress–density relation from the MD-simulated rear surface velocity profiles and compare it directly against the stress–density trajectories measured from the MD simulation itself. Deviations exist in the cases studied here, and these turn out to be related to the irreversibility between compression and release. Rarefaction and compression waves are observed to propagate with different sound velocities in some parts of the flow field, violating the basic assumption of isentropic hydrodynamic models and thus leading to systematic back-calculation errors. In particular, the step-like feature of the P(ρ) curve corresponding to phase transition may be completely missed owing to these errors. This kind of mismatch between inherent properties of matter and the basic assumptions of isentropic hydrodynamics has a fundamental influence on how the ramp loading method can be applied. [ABSTRACT FROM AUTHOR] more...
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- 2024
- Full Text
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20. Review of Research Progress on Acoustic Test Equipment for Hydrate-Bearing Sediments.
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Sun, Shihui, Zhang, Xiaohan, and Zhou, Yunjian
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SPEED of sound ,TEST systems ,ATTENUATION coefficients ,SOUND waves ,ACOUSTIC devices - Abstract
When acoustic waves propagate through hydrate samples, they carry extensive information related to their physical and mechanical properties. These details are comprehensively reflected in acoustic parameters such as velocity, attenuation coefficient, waveform, frequency, spectrum, and amplitude variations. Based on these parameters, it is possible to invert the physical and mechanical indicators and microstructural characteristics of hydrate samples, thereby addressing a series of issues in hydrate development engineering. This study first provides an overview of the current applications and prospects of acoustic testing in hydrate development. Subsequently, it systematically elaborates on the progress in research on acoustic testing systems for hydrate samples, including the principles of acoustic testing, ship-borne hydrate core acoustic detection systems, laboratory hydrate sample acoustic testing systems, and resonance column experimental systems. Based on this foundation, this study further discusses the development trends and challenges of acoustic testing equipment for hydrate-bearing sediments. [ABSTRACT FROM AUTHOR] more...
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- 2024
- Full Text
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21. High quality and sensitivity phononic crystal channel drop filter to detect ethyl lactate in mixtures of ethyl lactate and 2-butoxy ethanol.
- Author
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Omrani, Ehsan Mehdizadeh and Nazari, Fakhroddin
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POLYMETHYLMETHACRYLATE , *PHONONIC crystals , *CRYSTAL resonators , *FOOD additives , *SPEED of sound - Abstract
This paper introduces a new sensing approach utilizing a solid-solid phononic crystal (PnC) channel drop filter structure for the detection of varying molar fractions of Ethyl lactate within a mixture of Ethyl lactate and 2-butoxy ethanol. The sensor features a two-dimensional PnC constructed from poly methyl methacrylate as the background material, incorporating a regular arrangement of circular Tungsten columns. The design integrates a bus waveguide linked to two interconnected ring resonators, which are coupled to a drop waveguide. Each ring resonator is equipped with three strategically positioned pillars near the coupling region, allowing for the accommodation of varying concentrations of Ethyl lactate. The sensor's performance is significantly influenced by the ring resonators and the integrated pillars. It identifies specific resonance frequencies that shift in response to changes in Ethyl lactate concentrations within the resonators. The transmission resonance frequency exhibits valuable sensitivity to these concentration variations, reflecting the unique sound velocities and mass densities associated with each level of Ethyl lactate. The effectiveness of the proposed sensor is validated through coupled mode theory, demonstrating a close match with the device's observed behavior. The measured frequency range spans from 1.972 MHz to 1.979 MHz with a step size of 1 Hz. Notably, the sensor displays considerable characteristics, including an average quality factor of 90,613, an average sensitivity of 3816 Hz, an average figure of merit of 172, an average signal-to-noise ratio of 137, an average resolution of 22 Hz, an average damping ratio of 0.56 × 10− 5, and an average limit of detection of 34 × 10− 5. These results underscore the potential of the channel drop filter for the accurate detection of Ethyl lactate concentrations with high quality factor and sensitivity. The sensor can effectively identify variations in Ethyl lactate levels, which are prevalent in various applications, including pharmaceuticals and food additives. [ABSTRACT FROM AUTHOR] more...
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- 2024
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22. Atomic-scale visualization of defect-induced localized vibrations in GaN.
- Author
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Jiang, Hailing, Wang, Tao, Zhang, Zhenyu, Liu, Fang, Shi, Ruochen, Sheng, Bowen, Sheng, Shanshan, Ge, Weikun, Wang, Ping, Shen, Bo, Sun, Bo, Gao, Peng, Lindsay, Lucas, and Wang, Xinqiang
- Subjects
SCANNING transmission electron microscopy ,BAND gaps ,AB-initio calculations ,SPEED of sound ,THERMAL conductivity ,ELECTRON energy loss spectroscopy - Abstract
Phonon engineering is crucial for thermal management in GaN-based power devices, where phonon-defect interactions limit performance. However, detecting nanoscale phonon transport constrained by III-nitride defects is challenging due to limited spatial resolution. Here, we used advanced scanning transmission electron microscopy and electron energy loss spectroscopy to examine vibrational modes in a prismatic stacking fault in GaN. By comparing experimental results with ab initio calculations, we identified three types of defect-derived modes: localized defect modes, a confined bulk mode, and a fully extended mode. Additionally, the PSF exhibits a smaller phonon energy gap and lower acoustic sound speeds than defect-free GaN, suggesting reduced thermal conductivity. Our study elucidates the vibrational behavior of a GaN defect via advanced characterization methods and highlights properties that may affect thermal behavior. Authors identify three types of defect-derived phonon modes in GaN, including localized defect modes, a confined bulk mode, and a fully extended mode. The defects exhibit a smaller phonon energy gap and lower sound speeds, indicating reduced thermal conductivity. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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23. Competing Phases of Iron at Earth's Core Conditions From Deep‐Learning‐Aided ab‐initio Simulations.
- Author
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Li, Zhi and Scandolo, Sandro
- Subjects
- *
EARTH'S core , *FRICTION velocity , *SPEED of sound , *BODY centered cubic structure , *SEISMIC wave velocity - Abstract
The properties and relative stability of different structures of iron at the extreme conditions of pressure and temperature of relevance for the Earth's core were determined with ab‐initio atomistic simulations aided by a machine‐learning force‐field. We find that the body‐centered cubic (bcc) structure is mechanically stable at core temperatures, but its free energy is marginally higher than those of the hexagonal close‐packed and face‐centered cubic structures. The bcc structure is the only structure whose shear sound velocity matches seismic data. The small free‐energy difference between competing structures suggests that the role of impurities could be crucial in stabilizing the bcc structure in the inner core. Plain Language Summary: Determining the crystal structure and the elastic properties of the compound that forms the Earth's solid inner core is crucial to interpret seismic data. We know that the inner core is predominantly composed of iron, but laboratory‐based experiments and theoretical modeling haven't yet been able to constrain the crystal structure and the properties of pure Fe at the conditions of pressure and temperature found in the inner core. We have recently developed a deep‐learning‐aided atomistic simulation method that is able to determine Gibbs free energies of solids with quantum‐chemical accuracy (a few meV/atom). We find that although body‐centered cubic Fe is energetically slightly less favored than the hexagonal close‐packed form, the shear wave velocity of bcc Fe matches seismic data much better than all other crystal structures, suggesting that bcc is a strong candidate for the crystal structure of Fe in the Earth's inner core and could be stabilized by the presence of light elements in the core. Key Points: The body‐centered cubic structure of iron is mechanically stable at inner core conditionsThe hexagonal close‐packed structure is more stable, but small free energy differences could allow impurities to reverse this stabilityThe observed low shear velocity in the Earth's inner core is likely to be caused by the presence of the body‐centered cubic phase [ABSTRACT FROM AUTHOR] more...
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- 2024
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24. Acoustic black hole effect enhanced micro-manipulator.
- Author
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Yin, Qiu, Song, Haoyong, Wang, Zhaolong, Ma, Zhichao, and Zhang, Wenming
- Subjects
ACOUSTIC radiation force ,SPEED of sound ,FLEXIBLE electronics ,FLOW velocity ,CUSTOM design - Abstract
Microparticle manipulation is a critical concern across various fields including microfabrication, flexible electronics and tissue engineering. Acoustic-activated sharp structures have been designed as simple and flexible tools to manipulate microparticles with their good compatibility, fast response, and broad tunability. However, there still lacks rational acoustic-structure design for effective energy concentration at the acoustic-activated sharp structures for microparticle manipulation. Here, we present the acoustic black hole (ABH) effect as enhancement for the acoustic micro-manipulator. It provides great reliability, simplicity and ease of use, supporting custom design of high-throughput patterning modes. Moreover, compared to commonly used configurations, such as cylindrical or conical microneedles, those microneedles with ABH profile exhibit superior acoustic energy focusing at the tip and induce stronger acoustofluidic effects. The average acoustic flow velocity induced by the ABH microneedle is 154 times greater than that of the conical one and 45 times greater than that of the cylindrical microneedle. Besides, the average acoustic radiation force (ARF) produced by the ABH microneedle against acrylic microparticles is about 319 times greater than that of the cylindrical one and 16 times greater than that of the conical one. These results indicate that ABH design significantly enhances microparticle manipulation. We demonstrate this concept with ABH effect enhanced microparticle manipulation and study the parameters influencing its performance including operating frequency, operating voltage and particle diameter. Furthermore, considering the flexibility of this system, we employ it for various patterning and high-throughput microparticle manipulation. This work paves the way for controllable microparticle manipulation, holding great potential for applications in microfabrication and biomedicine. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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25. Mechanochemically responsive polymer enables shockwave visualization.
- Author
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Centellas, Polette J., Mehringer, Kyle D., Bowman, Andrew L., Evans, Katherine M., Vagholkar, Parth, Thornell, Travis L., Huang, Liping, Morgan, Sarah E., Soles, Christopher L., Simon, Yoan C., and Chan, Edwin P. more...
- Subjects
SPEED of sound ,DEFORMATIONS (Mechanics) ,STRAIN rate ,SOUND waves ,SPACE robotics - Abstract
Understanding the physical and chemical response of materials to impulsive deformation is crucial for applications ranging from soft robotic locomotion to space exploration to seismology. However, investigating material properties at extreme strain rates remains challenging due to temporal and spatial resolution limitations. Combining high-strain-rate testing with mechanochemistry encodes the molecular-level deformation within the material itself, thus enabling the direct quantification of the material response. Here, we demonstrate a mechanophore-functionalized block copolymer that self-reports energy dissipation mechanisms, such as bond rupture and acoustic wave dissipation, in response to high-strain-rate impacts. A microprojectile accelerated towards the polymer permanently deforms the material at a shallow depth. At intersonic velocities, the polymer reports significant subsurface energy absorption due to shockwave attenuation, a mechanism traditionally considered negligible compared to plasticity and not well explored in polymers. The acoustic wave velocity of the material is directly recovered from the mechanochemically-activated subsurface volume recorded in the material, which is validated by simulations, theory, and acoustic measurements. This integration of mechanochemistry with microballistic testing enables characterization of high-strain-rate mechanical properties and elucidates important insights applicable to nanomaterials, particle-reinforced composites, and biocompatible polymers. Understanding how materials respond to impacts at extreme strain rates is crucial, yet current approaches present significant challenges. Here, the authors report the use of a mechanophore-functionalized block copolymer to encode and report energy dissipation mechanisms in response to impacts. [ABSTRACT FROM AUTHOR] more...
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- 2024
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26. How Well Can Sound Tomograms Characterize Inner-Trunk Defects in Beech Trees from a Burned Plot?
- Author
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Musat, Elena C.
- Subjects
- *
MANUFACTURING processes , *SPEED of sound , *WOOD , *WOOD quality , *FOREST fires - Abstract
In recent years, forest fires have become increasingly common, but also more damaging phenomena. These aspects are reflected in significant economic losses that affect the quality and quantity of wood volumes that can be used for industrial processing. For this reason, knowing the quality of the wood is important, especially in fire-affected trees. Because visual analyses cannot always reflect the quality of the wood inside the trunk, the present research aimed to evaluate the extent to which modern techniques based on the transfer of sounds can identify internal wood defects. In this sense, 42 tomograms made from beech trees affected by a litter fire were compared with the relative resistances of the wood to drilling and with the real condition of the wood inside the trunk, as made visible through the growth cores taken with a Pressler drill. From the cumulative interpretation of the results, it was found that the trees affected by the fire have serious defects, which lead to the downgrading of the wood and are not reproduced by the tomograph to their true extent. Conversely, sound transfer speeds through wood are influenced by the presence of beech red heartwood, which leads to an increase in sound transfer speeds through wood, and that can alter the accuracy of the tomogram. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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27. Sound velocity measurement based on laser-induced micro-flyers.
- Author
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He, Z., Fang, Z., Huang, X., Xie, Z., Ye, J., Dong, J., Shu, H., Wang, P., Jia, G., Zhang, F., Xiong, J., Cheng, B., Tu, Y., Zhang, J., and Fu, S.
- Subjects
- *
VELOCIMETRY , *SOUND measurement , *VELOCITY measurements , *TRAFFIC safety , *VELOCITY , *EQUATIONS of state , *SPEED of sound - Abstract
The measurement of high-pressure sound velocity in solid materials is crucial for developing constitutive equations and equations of state for materials in extreme stress–strain rate conditions. In this study, we propose a novel method for high-pressure sound velocity measurement using laser-induced micro-flyer technology. By optimizing laser driving conditions and target structure design, we measure high-pressure sound velocity using the "reverse-impact geometry" approach. The well-established Photon Doppler Velocimetry system allows for high-precision, single-shot measurements of both flyer velocity and particle velocity histories. A systematic error analysis shows that the longitudinal sound velocity of aluminum obtained in this experiment is consistent with data from traditional devices, such as gas guns, within the error margin. Finally, we analyze the potential application value of this method in laser technology as well as high-pressure dynamic responses of materials, and conclude the current shortcomings and possible improvements of this method. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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28. Sound transmission loss analysis of double-walled sandwich functionally graded carbon nanotube-reinforced composite magneto-electro-elastic plates under thermal environment.
- Author
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Farahmand-Azar, Bahman, Pourmoosavi, Ghazaleh, and Talatahari, Siamak
- Subjects
- *
SHEAR (Mechanics) , *SANDWICH construction (Materials) , *HAMILTON'S principle function , *TRANSMISSION of sound , *SPEED of sound , *DOUBLE walled carbon nanotubes , *COMPOSITE plates - Abstract
Sandwich structures with functionally graded (FG) cores have gained interest in vibroacoustic applications. This article considers the vibroacoustic properties of double-walled sandwich magneto-electro-elastic (MEE) plates with a functionally graded carbon nanotube-reinforced composite (FG-CNTRC) core layer in a thermal environment. A coupled multiphysics model is developed based on third-order shear deformation theory (TSDT) and acoustic-structure interaction. Special attention is paid to the transmission loss of this arrangement for simply supported and clamped boundaries for four different kinds of CNT distributions, namely, UD, FG-V, FG-O, and FG-X. Sound velocity potential, normal velocity continuity conditions, and Hamilton's principle are used to generate the coupled vibroacoustic equations, which are then solved using the Galerkin method. The effects of boundary conditions, CNT distributions, cavity depth, multiphysics coupling fields, and temperature on the STL are comprehensively studied. The results provide guidelines for tailoring the dynamic response of these materials to achieve enhanced acoustic insulation performance. It enhances fundamental understanding and enables the engineering design of multilayered composite panels with optimized vibration and noise control capabilities. [ABSTRACT FROM AUTHOR] more...
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- 2024
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- View/download PDF
29. Non-Invasive Characterization of Different Saccharomyces Suspensions with Ultrasound.
- Author
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Geier, Dominik, Mailänder, Markus, Whitehead, Iain, and Becker, Thomas
- Subjects
- *
SPEED of sound , *ATTENUATION coefficients , *BIOLOGICAL monitoring , *ULTRASONIC measurement , *FERMENTATION products industry - Abstract
In fermentation processes, changes in yeast cell count and substrate concentration are indicators of yeast performance. Therefore, monitoring the composition of the biological suspension, particularly the dispersed solid phase (i.e., yeast cells) and the continuous liquid phase (i.e., medium), is a prerequisite to ensure favorable process conditions. However, the available monitoring methods are often invasive or restricted by detection limits, sampling requirements, or susceptibility to masking effects from interfering signals. In contrast, ultrasound measurements are non-invasive and provide real-time data. In this study, the suitability to characterize the dispersed and the liquid phase of yeast suspensions with ultrasound was investigated. The ultrasound signals collected from three commercially available Saccharomyces yeast were evaluated and compared. For all three yeasts, the attenuation coefficient and speed of sound increased linearly with increasing yeast concentrations (0.0–1.0 wt%) and cell counts (R2 > 0.95). Further characterization of the dispersed phase revealed that cell diameter and volume density influence the attenuation of the ultrasound signal, whereas changes in the speed of sound were partially attributed to compositional variations in the liquid phase. This demonstrates the ability of ultrasound to monitor industrial fermentations and the feasibility of developing targeted control strategies. [ABSTRACT FROM AUTHOR] more...
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- 2024
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30. Towards the Optimization of Polyurethane Aerogel Properties by Densification: Exploring the Structure–Properties Relationship.
- Author
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Merillas, Beatriz, García‐González, Carlos A., Álvarez‐Arenas, Tomás Enrique Gómez, and Rodríguez‐Pérez, Miguel Ángel
- Subjects
- *
SPEED of sound , *THERMAL insulation , *SOUNDPROOFING , *HEAT transfer , *AEROGELS - Abstract
The aerogel performance for industrial uses can be tailored using several chemical and physical strategies. The effects of a controlled densification on polyurethane aerogels are herein studied by analyzing their textural, mechanical, sound, optical, and thermal insulating properties. The produced aerogels are uniaxially compressed to different strains (30%–80%) analyzing the consequent changes in the structures and, therefore, final properties. As expected, their mechanical stiffness can be significantly increased by compression (until 55‐fold higher elastic modulus for 80%‐strain), while the light transmittance does not noticeably worsen until it is compressed more than 60%. Additionally, the modifications produced in the heat transfer contributions are analyzed, obtaining the optimum balance between density increase and pore size reduction. The minimum thermal conductivity (14.5%‐reduction) is obtained by compressing the aerogel to 50%‐strain, where the increment in the solid conduction is surpassed by the reduction of the radiative and gas contributions. This strategy avoids tedious chemical modifications in the synthesis procedure to control the final structure of the aerogels, leading to the possibility of carefully adapting their structure and properties through a simple method such as densification. Thus, it allows to obtain aerogels for current and on‐demand applications, which is one of the main challenges in the field. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
31. A Non-Destructive Measurement Approach for the Internal Temperature of Shiitake Mushroom Sticks Based on a Data–Physics Hybrid-Driven Model.
- Author
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Zhang, Xin, Zeng, Xinwen, Wei, Yibo, Zheng, Wengang, and Wang, Mingfei
- Subjects
SPEED of sound ,ATMOSPHERIC temperature ,TEMPERATURE measurements ,SHIITAKE ,MACHINE performance ,HYBRID systems - Abstract
This study aimed to develop a non-destructive measurement method utilizing acoustic sensors for the efficient determination of the internal temperature of shiitake mushroom sticks during the cultivation period. In this research, the sound speed, air temperature, and moisture content of the mushroom sticks were employed as model inputs, while the temperature of the mushroom sticks served as the model output. A data–physics hybrid-driven model for temperature measurement based on XGBoost was constructed by integrating monotonicity constraints between the temperature of the mushroom sticks and sound speed, along with the condition that limited the difference between air temperature and stick temperature to less than 2 °C. The experimental results indicated that the optimal eigenfrequency for applying this model was 850 Hz, the optimal distance between the sound source and the shiitake mushroom sticks was 8.7 cm, and the temperature measurement accuracy was highest when the moisture content of the shiitake mushroom sticks was in the range of 56~66%. Compared to purely data-driven models, our proposed model demonstrated significant improvements in performance; specifically, RMSE, MAE, and MAPE decreased by 74.86%, 77.22%, and 69.30%, respectively, while R
2 increased by 1.86%. The introduction of physical knowledge constraints has notably enhanced key performance metrics in machine learning-based acoustic thermometry, facilitating efficient, accurate, rapid, and non-destructive measurements of internal temperatures in shiitake mushroom sticks. [ABSTRACT FROM AUTHOR] more...- Published
- 2024
- Full Text
- View/download PDF
32. Study on the Performance of High-Performance Mortar (HPM) Prepared Using Sodium-Silicate-Modified Graphite Tailing Sand.
- Author
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Jiang, Ruixin, Wang, Zhengjun, Du, Yingxin, and Wen, Yajing
- Subjects
SPEED of sound ,POROSITY ,SCANNING electron microscopy ,SOLUBLE glass ,INFRARED spectroscopy - Abstract
In order to rationalize the consumption of graphite tailing sand and reduce its pollution of the environment—with sodium silicate being a commonly used activator for improving the strength of concrete composites—in this study, the joint effects of sodium silicate (SS) and graphite tail sand (GT) on the strength and frost resistance of graphite tail sand high-performance mortar (GT-HPM) were investigated. Experiments were conducted to evaluate the bulk density, water absorption, compressive strength, speed of sound, and working performance status of GT-HPM before and after freezing and thawing at different SS dosages and different GT substitution rates. The microstructural properties of GT-HPM were also analyzed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM/EDS). The results showed that 4% SS doping improved the performance of GT-HPM more obviously. Moreover, with an increase in the GT substitution rate, the mechanical properties and frost resistance of GT-HPM increased firstly and then decreased, and the best performance of GT-HPM was obtained when the GT substitution rate was 20%. At 6% SS doping, the performance of GT-HPM gradually decreased with the increase in the graphite tailing sand substitution rate. FT-IR testing showed that there was no significant change with the type of hydration products used, and the Si–O–T absorption peak and average bond length of GT-4 were the largest. SS and GT promoted the generation of hydration products. Microstructural analysis showed that 4% SS promoted the hydration reaction; in addition, an appropriate amount of GT improved the pore structure of HPM, increased the strength and frost resistance, and provided fundamental insights for the subsequent comprehensive utilization of graphite tailing sand. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
33. Range-Domain Subspace Detector in the Presence of Direct Blast for Forward Scattering Detection in Shallow-Water Environments.
- Author
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Luo, Jiahui, Sun, Chao, and Li, Mingyang
- Subjects
SPEED of sound ,SONAR ,PRIOR learning ,DETECTORS ,A priori - Abstract
This paper aims to detect a target that crosses the baseline connecting the source and the receiver in shallow-water environments, which is a special scenario for a bistatic sonar system. In such a detection scenario, an intense sound wave, known as the direct blast, propagates directly from the source to the receiver without target scattering. This direct blast usually arrives at the receiver simultaneously with the forward scattering signal and exhibits a larger intensity than the signal, posing a significant challenge for target detection. In this paper, a range-domain subspace is constructed by the horizontal distance between the source/target and each element of a horizontal linear array (HLA) when the ranges of environmental parameters are known a priori. Meanwhile, a range-domain subspace detector based on direct blast suppression (RSD-DS) is proposed for forward scattering detection. The source and the target are located at different positions, so the direct blast and the scattered signal are in different range-domain subspaces. By projecting the received data onto the orthogonal complement subspace of the direct blast subspace, the direct blast can be suppressed and the signal that lies outside the direct blast subspace is used for target detection. The simulation results indicate that the proposed RSD-DS exhibits a performance close to the generalized likelihood ratio detector (GLRD) while requiring less prior knowledge of environments (only known are the ranges of the sediment sound speed and the bottom sound speed), and its robustness to environmental uncertainties is better than that of the latter. Moreover, the proposed RSD-DS exhibits better immunity against the direct blast than the GLRD, since it can still work effectively at a signal-to-direct blast ratio (SDR) of −30 dB, while the GLRD stops working in this case. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
34. A perspective review on the role of engine sound in speed perception and control: state of the art and methodological suggestions.
- Author
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Prpic, Valter, Gherri, Elena, and Lugli, Luisa
- Subjects
MOTION perception (Vision) ,SPEED of sound ,PERCEIVED control (Psychology) ,AUDITORY perception ,AUDIO frequency - Abstract
In this review we focus on the role of in-car sound, specifically the artificial engine sounds, on drivers' speed perception and control, a topic that has received little attention so far. Previous studies indicate that removing or reducing engine sound leads drivers to underestimate speed and, consequently, to drive faster. Furthermore, evidence suggests that specific sound frequencies could play a role in this process, highlighting the importance of in-car sound features. First, we show that the amount of research in the field is scarce and rather outdated, and that this is largely due to the fact that industrial research is subject to very few publications. Then, we examine benefits and limitations of different research paradigms used and we propose a protocol to investigate systematically the phenomenon. In particular, we argue for the benefits of a wider use of psychophysical methods in speed perception, a field that has been typically explored by means of driving simulation. Finally, we highlight some methodological and statistical limitations that might impact the interpretation of the evidence considered. Our methodological considerations could be particularly useful for researchers aiming to investigate the impact of sound on speed perception and control, as well as for those involved in the design of in-car sounds. These are particularly relevant for the design of electric vehicles, which represent a challenge but also the ideal testing ground to advance the knowledge in the field. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
35. On the Binding Energy of Atoms in Crystals of Noble Gases and Metals and the Speed of Sound.
- Author
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Dall'Osso, Aldo
- Subjects
FORCE & energy ,SPEED of sound ,RARE earth metals ,YOUNG'S modulus ,SOLID state physics - Abstract
The speed of sound depends on the structure and material properties of the crystal, such as density and Young's modulus. On the other hand, from atomistic arguments it is possible to associate Young's modulus with other material properties. These observations lead to a relationship between binding energy of atoms in a crystal (which is one of the parameters appearing in Mie-Lennard-Jones potential), speed of sound in the longitudinal direction and mass of one atom in the lattice. This subject was addressed by several authors, providing different implementations of this relation. A literature review on this topic is made and the mathematical derivation of the relation is carried out. Applications of this relationship to rare gases, some metals and some rare earths are presented and the results compared to others taken from literature. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
36. High-resolution acoustically informed maps of sound speed.
- Author
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Loranger, Scott, DeCourcy, Brendan, Zhang, Weifeng Gordon, Lin, Ying-Tsong, and Lavery, Andone
- Subjects
SPEED of sound ,OCEANOGRAPHY ,OCEANOGRAPHERS ,ELECTRIC conductivity ,WATER masses - Abstract
As oceanographic models advance in complexity, accuracy, and resolution, in situ measurements must provide spatiotemporal information with sufficient resolution to inform and validate those models. In this study, water masses at the New England shelf break were mapped using scientific echosounders combined with water column property measurements from a single conductivity, temperature, and depth (CTD) profile. The acoustically-inferred map of sound speed was compared with a sound speed cross section based on two-dimensional interpolation of multiple CTD profiles. Long-range acoustic propagation models were then parameterized by the sound speed profiles estimated by the two methods and differences were compared. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
37. Hydration behavior of D-calcium pantothenate (vitamin B5) in the presence of sugar-based deep eutectic solvents at different temperatures: experimental and theoretical study
- Author
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Nadia Beladi, Fariba Ghaffari, Behrang Golmohammadi, and Hemayat Shekaari
- Subjects
Deep eutectic solvents ,D-calcium pantothenate ,Density ,Speed of sound ,Redlich-Meyer equation ,Medicine ,Science - Abstract
Abstract Considerable efforts have been devoted in recent years to enhancing the efficacy medicinal substance, leading to the discovery of innovative drug formulations and delivery techniques. The successful design of these processes necessitates a profound understanding at the molecular level of how these substances interact with biological membranes. Thorough thermodynamic investigations provide invaluable insights into these interactions and aid in selecting suitable compounds for pharmaceutical production. This study aims to determine the density and speed of sound for D-calcium pantothenate in mixtures of water and deep eutectic solvents (DESs), specifically choline chloride/sucrose, choline chloride/ glucose, and choline chloride/ fructose (with 2:1 molar ratio) over a temperature range of 288.15 K to 318.15 K under atmospheric pressure. In order to predict the behavior of molecules, COSMO model (the Conductor-Like Screening Model) offer complementary strengths in quantum chemistry. This approach allows for calculating solvation free energies, making it ideal for predicting properties like solubility, where understanding solvent-solute interactions is crucial. By correlating the measured parameters using standard relationships, important partial molar parameters such as apparent molar volumes and apparent molar isentropic compressibility are calculated. Additionally, apparent molar isobaric expansion, and Hepler’s constant are derived from the density and speed of sound data. The experimental apparent molar volumes, and apparent molar isentropic compressibility data is fitted to the Redlich-Meyer equation to obtain significant quantities such as standard partial molar volume, and partial molar isentropic compression. The comprehensive thermodynamic analysis of this studied system holds immense significance for advancements in the pharmaceutical industry. more...
- Published
- 2024
- Full Text
- View/download PDF
38. Effects of the photospheric cut-off on the p-mode frequency stability.
- Author
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Kolotkov, Dmitrii Y, Broomhall, Anne-Marie, and Hasanzadeh, Amir
- Subjects
- *
SOLAR magnetic fields , *SOLAR oscillations , *ACOUSTIC resonators , *ASTEROSEISMOLOGY , *SPEED of sound - Abstract
Sub-photospheric acoustic resonators allow for the formation of standing p-mode oscillations by reflecting acoustic waves with frequencies below the acoustic cut-off frequency. We employ the Klein–Gordon equation with a piecewise acoustic potential to study the characteristic frequencies of intermediate-degree p modes, modified by the cut-off effect. For a perfectly reflective photosphere, provided by the infinite value of the acoustic cut-off frequency, characteristic discrete frequencies of the trapped p modes are fully prescribed by the width of the acoustic potential barrier. Finite values of the acoustic cut-off frequency result in the reduction of p-mode frequencies, associated with the decrease in the sound speed by the cut-off effect. For example, for a spherical degree of |$\ell = 100$| , characteristic p-mode frequencies are found to decrease by up to 200 µHz and the effect is more pronounced for higher radial harmonics. The frequency separation between two consecutive radial harmonics is shown to behave non-asymptotically with non-uniform spacing in the radial harmonic number due to the cut-off effect. We also show how the 11-yr variability of the Sun's photospheric magnetic field can result in the p-mode frequency shifts through the link between the acoustic cut-off frequency and the plasma parameter |$\beta$|. Using this model, we readily reproduce the observed typical amplitudes of the p-mode frequency shift and its phase behaviour relative to other 11-yr solar cycle proxies. The use of the developed model for comparison with observations requires its generalization for 2D effects, more realistic profiles of the acoustic potential, and broad-band stochastic drivers. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
39. Inferring the Speed of Sound and Wind in the Nighttime Martian Boundary Layer From Impact‐Generated Infrasound.
- Author
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Froment, Marouchka, Xu, Zongbo, Lognonné, Philippe H., Larmat, Carène, Garcia, Raphael F., Drilleau, Mélanie, Delbridge, Brent G., Spiga, Aymeric, Kawamura, Taichi, and Beucler, Éric
- Subjects
- *
ATMOSPHERIC boundary layer , *CLIMATE change models , *GROUP velocity , *MARTIAN surface , *BOUNDARY layer (Aerodynamics) , *SPEED of sound - Abstract
The properties of the first kilometers of the Martian atmospheric Planetary Boundary Layer have until now been measured by only a few instruments and probes. InSight offers an opportunity to investigate this region through seismoacoustics. On six occasions, its seismometers recorded short low‐frequency waveforms, with clear dispersion between 0.4 and 4 Hz. These signals are the air‐to‐ground coupling of impact‐generated infrasound, which propagated in an low‐altitude atmospheric waveguide. Their group velocity depends on the structure of effective sound speed in the boundary layer. Here, we conduct a Bayesian inversion of effective sound speed up to 2,000 m altitude using the group velocity measured for events S0981c, S0986c and S1034a. The inverted effective sound speed profiles are in good agreement with estimates provided by the Mars Climate Database. Differences between inverted and modeled profiles can be attributed to a local wind variation in the impact→station direction, of amplitude smaller than 2 m/s. Plain Language Summary: The Martian Planetary Boundary Layer corresponds to the first few kilometers of the atmosphere. The InSight lander offers the opportunity to investigate its properties via the coupling of seismic and acoustic waves. Impact‐generated infrasound waves were recorded for the first time on Mars by the seismometers of the InSight mission. These infrasound waves propagated in an atmospheric waveguide in the first kilometers above the Martian surface, and thus present a frequency‐dependent group velocity. This frequency‐dependence, also known as a dispersion relation, is influenced by the structure of the speed of sound in the waveguide. Here, we use group velocity measured for events S0981c, S0986c and S1034a to invert the variations of effective sound speed between 0 and 2,000 m altitude. For the three events, the inverted profiles are in good agreement with estimates provided by the Mars Climate Database using global climate modeling. The differences between inverted and modeled profiles can be attributed to a local variation in wind in the impact→station direction, with magnitude smaller than 2 m/s. Key Points: InSight recorded impact‐generated infrasound on Mars. Their group velocity is sensitive to the structure of the atmospheric boundary layerWe conduct a Bayesian inversion of effective sound speed profiles with altitude based on group velocities measured for three impact eventsThe inverted profiles provide an indirect measurement of the Martian boundary layer, and validate models of the Mars Climate Database [ABSTRACT FROM AUTHOR] more...
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- 2024
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40. Acoustic Skyrmionic Mode Coupling and Transferring in a Chain of Subwavelength Metastructures.
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Sun, Wen‐Jun, Zhou, Nong, Chen, Wan‐Na, Sheng, Zong‐Qiang, and Wu, Hong‐Wei
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MODE-coupling theory (Phase transformations) , *SPEED of sound , *ACOUSTIC resonators , *ACOUSTIC field , *SKYRMIONS - Abstract
Skyrmions, a stable topological vectorial textures characteristic with skyrmionic number, hold promise for advanced applications in information storage and transmission. While the dynamic motion control of skyrmions has been realized with various techniques in magnetics and optics, the manipulation of acoustic skyrmion has not been done. Here, the propagation and control of acoustic skyrmion along a chain of metastructures are shown. In coupled acoustic resonators made with Archimedes spiral channel, the skyrmion hybridization is found giving rise to bonding and antibonding skyrmionic modes. Furthermore, it is experimentally observed that the skyrmionic mode of acoustic velocity field distribution can be robustly transferred covering a long distance and almost no distortion of the skyrmion textures in a chain of metastructures, even if a structure defect is introduced in the travel path. The proposed localized acoustic skyrmionic mode coupling and propagating is expected in future applications for manipulating acoustic information storage and transfer. [ABSTRACT FROM AUTHOR] more...
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- 2024
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41. Research on the online monitoring technique for transformer oil level based on ultrasonic sensors.
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Zhu, Yongcan, Bing, Kaiyang, Liu, Dongyang, He, Jiacheng, Shi, Haonan, and Huang, Xinbo
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INSULATING oils , *FINITE element method , *BASE oils , *SPEED of sound , *FAULT diagnosis - Abstract
In order to solve the problem of remote oil level measurement for unmanned transformers, this paper proposes an online monitoring technology for transformer oil level based on ultrasonic sensors. Subsequently, a finite element model and experimental testing platform were constructed to analyse and verify the influencing factors of the transformer oil level sensors. The results indicated that there is a lower measurement error at 140 kHz in the ultrasonic frequency range of 20–320 kHz, which can be selected as the recommended frequency. The impurities in the oil and the thickness of the tank wall have a slight impact on the accuracy of oil level measurement, and can lead to a decrease in the signal‐to‐noise ratio of the echo. Furthermore, as the speed of sound increases by about 4 m/s, for every 1°C increase in oil temperature, it is necessary to calibrate the measurement results based on the oil temperature. The test results of actual experimental transformers showed that the designed online monitoring device can achieve high‐precision monitoring of transformer oil level, with a relative error generally less than 3%. [ABSTRACT FROM AUTHOR] more...
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- 2024
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42. Experimental target strength measurements of pteropods and shrimp emphasize the importance of scattering model inputs.
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Lucca, Brandyn M and Warren, Joseph D
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SOUND wave scattering , *SPEED of sound , *ACOUSTIC models , *FISHING nets , *BACKSCATTERING - Abstract
Shrimp and shelled pteropods are ecologically important organisms that can produce significant amounts of water column backscatter. Few studies have experimentally measured both target strength (TS) and scattering model inputs for individual shrimp and shelled pteropods, especially from the meso- and bathypelagic. We captured animals from net trawls throughout the northeast Pacific and northwest Atlantic continental shelves between 2016 and 2020. We measured morphology, density and sound speed contrasts, and broadband TS (35–75, 110–230 kHz) from tethered individuals at sea and on land in scientific aquaria. Experimentally measured TS was used to test scattering model performance. Differences in measured mean length-to-radius ratios and density contrasts of epipelagic shrimp (10–13 and 1.02–1.03) were statistically greater than for mesopelagic species (8–9 and 1.04–1.05). Differences between predicted and measured shrimp TS averaged over measurement bandwidths were <2 dB, which is similar to previous studies. Conversely, pteropod TS model predictions differed from measurements by >4 dB, with species with elongated shapes having larger differences, likely due to shell shape and uncertainty surrounding material properties. Widely used physics-based acoustic scattering models may significantly underestimate uncertainty in TS predictions for these animals. [ABSTRACT FROM AUTHOR] more...
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- 2024
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43. Plane-wave and cylindrical-wave acoustic reflection from a marine sediment with layering representative of the New England Mud Patch.
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Buckingham, Michael J.
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HELMHOLTZ equation , *MARINE sediments , *REFLECTANCE , *ACOUSTIC reflection , *SPEED of sound - Abstract
An analysis is presented of reflection from a marine sediment consisting of a homogeneous mud layer overlying a sand-mud basement, the latter with an upward-refracting, inverse-square sound speed profile. Such layering is representative of the sediment at the New England Mud Patch (NEMP). By applying appropriate integral transforms and their inverses to the Helmholtz equations for the ocean and the two sediment layers, along with the boundary conditions, a Sommerfeld–Weyl type of wavenumber integral is obtained for the cylindrical-wave reflection coefficient of the sediment, R. A stationary phase evaluation of this integral yields a closed-form expression for the plane-wave reflection coefficient, R0. In the absence of attenuation, the plane-wave solution exhibits total reflection up to a critical grazing angle, ac, but when attenuation in the sediment is introduced, the region of total reflection in |R0| is replaced by a sequence of contiguous peaks. With realistic levels of sediment attenuation, the cylindrical-wave solution, |R|, exhibits a quasi-critical grazing angle, less than ac, which is strongly dependent on the source-plus-receiver height above the seabed, which is mildly dependent on the depth of the mud layer but is essentially independent of frequency. Such behavior is consistent with independent experimental observations at the NEMP. [ABSTRACT FROM AUTHOR] more...
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- 2024
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44. Modelling approaches to multibeam echosounders for sound field characterizationa).
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Smith, Michael
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ACOUSTIC radiators , *ACOUSTIC field , *SPEED of sound , *ACOUSTIC models , *MARINE biology - Abstract
Concern over the impact of multibeam echosounders (MBES) on marine life has increased in recent years. A thorough impact assessment of acoustic sources requires both accurate modeling of the source and radiated sound field, and a biological assessment. The Joint Industry Program Acoustic Modelling Workshop in 2022 provided a set of verification scenarios for a deep-water MBES to compare modelling approaches and assess agreement across models. This work presents several relevant models designed to compute both the MBES beam patterns and propagated acoustic field. Key acoustic metrics used in impact assessment were calculated and compared using these models. The work confirmed that geometrical acoustics is well suited to the unique radiation patterns of MBES. Ray-tracing programs are relevant as well at short ranges and at long horizontal distances in the presence of large sound speed gradients. The estimation of cumulative sound exposure along a survey track is most often dominated by exposure to the main transmit beam of each sector. Accurate modelling of the near field was demonstrated to have a direct impact on final acoustic metrics and threshold ranges for various marine mammal hearing groups. [ABSTRACT FROM AUTHOR] more...
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- 2024
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45. Is Passynski's Approach to Hydration Numbers Consistent with Thermodynamics?
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Marczak, Wojciech
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SPEED of sound , *MOLE fraction , *AQUEOUS solutions , *MOLECULAR interactions , *COMPRESSIBILITY - Abstract
Hydrophilic and hydrophobic phenomena occur in aqueous solutions. Despite the complex nature of the molecular interactions, the propensity of molecules and ions to hydration is sometimes characterized by a single "hydration number". Passynski's method for determining the hydration numbers in dilute aqueous solutions belongs to the group of methods based on the analysis of the isentropic compressibility of a mixture. Isentropic compressibility is a thermodynamic material constant; thus, the paper deals with Passynski's approach discussed in terms of thermodynamics. First, Passynski's assumptions were applied to the volume of the mixture. Subsequent strict thermodynamic derivation led to a formula for the hydration number which resembled that of Onori rather than the original one. Passynski's number turned out to be inconsistent with the thermodynamics and mechanics of fluids. This is a rather purely empirical measure of the slope of the dependence of isentropic compressibility on the solute mole fraction in a dilute aqueous solution. Being the quotient of the slope and the isentropic compressibility of pure water, Pasynski's numbers are more convenient to analyze and discuss than the slopes themselves. Conclusions about molecular interactions based on these numbers must be treated with considerable caution. [ABSTRACT FROM AUTHOR] more...
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- 2024
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46. Cosmographic analysis of the dynamics of universe in higher dimensional compactified space with Tachyonic field.
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Singha, Anup Kumar, Debnath, Ujjal, and Pradhan, Anirudh
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SPEED of sound , *HYPERBOLIC functions , *SCALAR field theory , *COSMOLOGICAL constant , *TRIGONOMETRIC functions - Abstract
In this work, the considered model is contained in higher dimensional compactified space in the form of M4 × M6, where M6 is compact inner space. Since, for a higher dimensional cosmological model, Tachyon matter is an automatic and fantastic choice, we have supposed that the scalar field is driven by Tachyon together with the higher dimensional cosmological constant Λ ¯ . Our observation is that the theory provides a good solution for the cosmological scale factor of the present universe. Here, it is important that the forms of the tachyonic field ϕ and potential V are simple trigonometric hyperbolic functions. We study the cosmographical parameters like equation of state parameter, statefinder parameters, jerk, snap, and lerk parameters. The graphical representations of cosmological parameters show the overall evolution of the universe under a tachyonic field in a higher dimensional model. The classical stability of the model due to small perturbations both for dark energy and metric are examined by the study of the square speed of sound and by the linear perturbation method. We also analyzed the model in ω−ω′ and r−s cosmological plane. [ABSTRACT FROM AUTHOR] more...
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- 2024
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47. Exploring the molecular interactions of dorzolamide hydrochloride in aqueous solutions: a comprehensive study using thermophysical techniques and molecular simulations across various temperatures.
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Rayinuthala, Yesupadamu, Medepalli, David Raju, Munnangi, Srinivasa Reddy, Nayeem, Sk Md, and Ravulapalli, Lakshmi Tulasi
- Subjects
- *
ISENTROPIC compression , *SPEED of sound , *MOLECULAR dynamics , *MOLECULAR interactions , *REFRACTIVE index , *MOLECULAR volume - Abstract
This research begins with the initial assessment of key physical properties—density (ρ), speed of sound (u), and refractive index (nD) in binary aqueous solutions of dorzolamide hydrochloride. These properties were measured in solutions with varying molalities, ranging from 0.0 to 0.0276, under standard atmospheric conditions and at temperatures between 300.15 and 320.15 K. From these measurements, we were able to calculate a range of important parameters, including the apparent molar volume (Vϕ), its limiting values ( V ϕ 0 ), limiting apparent molar expansivity ( E ϕ 0 ), Helper's constant ( ∂ 2 V ϕ 0 ∂ T 2 ), apparent molar isentropic compression (κϕ), and its limiting values ( κ ϕ 0 ), specific refraction (RD), molar refraction (RM), and hydration number (nh). These calculated values provided insights into the strong interactions between the solute and solvent in the liquid system. They also shed light on the presence of various molecular interactions, such as inter- and intramolecular hydrogen bonds, dipole–dipole, and dipole-induced-dipole interactions, as well as the ability of the solute to influence the structure of the surrounding water molecules. Additionally, we derived the densities of dorzolamide hydrochloride solutions from molecular dynamics (MD) simulations, which showed a strong correlation with our experimental findings, underscoring the reliability of MD simulations in such studies. In the end, our combined study on dorzolamide hydrochloride in water demonstrates that it shapes structures because it has lower volumetric properties and stronger hydrogen bonds in MD simulations. More alchemical free energy calculations show that there are big changes in solvation energies. This is important for understanding how dorzolamide hydrochloride works in water. [ABSTRACT FROM AUTHOR] more...
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- 2024
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48. Magnesium aluminum spinel for ultrasonic temperature sensing based on guided waves.
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Haijian Liang, Xinhui Wang, and Hongxin Xue
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ULTRASONIC propagation ,ALUMINUM crystals ,ALUMINUM oxide ,SPEED of sound ,ENGINE testing - Abstract
Sensors are crucial for measuring combustion temperatures in aerospace and aviation engine testing. However, current sensors have poor oxidation resistance, low impact resistance, limited lifespan, and inadequate temperature measurement accuracy, often resulting in unsatisfactory testing outcomes. New sensor designs are urgently needed to address these issues. We propose a new sensor with advanced materials and technologies, based on the principle of ultrasonic guided wave temperature measurement with magnesium aluminum spinel (MgAl
2 O4 ) and magnesium-doped aluminum oxide crystals as ultrasonic waveguides.The design parameters of this sensor’s sensitive elements were meticulously crafted. Finite element method simulations were then conducted to assess the impact of groove depth on ultrasonic propagation characteristics. Ultrasonic temperature sensors with spinel and magnesiumdoped aluminum oxide were fabricated via the laser heated pedestal growth method. These sensors were calibrated in an oxidative environment, demonstrating a temperature sensitivity of 0.48 m/s·°C and a repeatability of 95% across a range from 20 °C to 1600 °C. By comparison among the three materials at a constant temperature, the sound velocity of sapphire was the fastest, followed by magnesia-doped alumina, while magnesia-alumina spinel was slowest. Thus, magnesia-alumina spinel can be considered an effective acoustic waveguide material for facile signal acquisition and hightemperature resolution. The proposed sensor design shows promise for applications in environments prone to oxidative erosion and high temperatures, offering an innovative solution for reliable temperature measurement within the harsh environments of aerospace and aviation engines. [ABSTRACT FROM AUTHOR] more...- Published
- 2024
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49. The Side-Release Method Measures the High-Pressure Sound Velocity of Iron Using Line-Spatially Resolved DISAR.
- Author
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Chen, Long, Liu, Cangli, Tang, Longhuang, Ma, Heli, Jia, Xing, Tao, Tianjiong, Liu, Shenggang, Chen, Yongchao, Wang, Xiang, Wu, Jian, Li, Chengjun, Liu, Dameng, Weng, Jidong, and Liu, Huan
- Subjects
SPEED of sound ,ACOUSTICS ,SOLID state physics ,EARTH'S core ,LASER interferometry - Abstract
The study of high-pressure sound velocity is an important part of shock wave physics, and the study of ultra-high pressure sound velocity of iron is of great significance to many research fields such as geophysics, solid state physics, and crystallography. At present, the measurement of sound velocity is usually carried out by the catch-up sparse wave method and windowed VISAR technology, which is complex in structure and not highly adaptable. In particular, for the ultra-high pressure sonic velocity measurement of metals, it is limited by the loading platform and window materials and cannot realize the high temperature and high-pressure environment of the earth's inner core. In this paper, the sound velocity measurement of iron under high temperature and high-pressure environment (78 GPa) is realized based on the two-stage light gas cannon experimental platform. The side-side sparse wave method was used to establish a coupling model of high-spatially resolved optical group and fiber bundle. A multiplexed all-fiber laser interferometry velocity measurement system (DISAR) was built, and the spatial resolution was better than 20 μm. In this paper, we will provide a feasible route for a method for measuring the high spatiotemporal resolution velocity. [ABSTRACT FROM AUTHOR] more...
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- 2024
- Full Text
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50. The Relationship between the Fresh Sludge Ceramsite Concrete's Fluidity and the Sludge Ceramsite's Dispersion.
- Author
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Yu, Yehan, Xiao, Bing, Cao, Zihao, Cheng, Bingling, Peng, Xi, and Wang, Hui
- Subjects
LIGHTWEIGHT concrete ,SPEED of sound ,COMPRESSIVE strength ,EXTERIOR walls ,X-ray diffraction - Abstract
Sludge ceramsite (SC) can be utilized as a lightweight aggregate in concrete, especially in external wall materials, due to the increasing volume of polluted sludge, which contributes to water system deterioration and poses greater threats to human health. The influence of the fresh mortar's slump flow on the dispersion of ceramsite was studied. The ultrasonic sound velocity, capillary water absorption rate, compressive strength, and coefficient of variation (CV) were measured in this study. Thermogravimetric (TG) analysis, ultra depth-of-field microscope scanning, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) were used to analyze the performance mechanism of the ceramsite concrete. The results indicated that adding SC could reduce the fluidity of the fresh concrete, with a reduction by rates of up to 2.04%. The addition of WRA could improve the fluidity by rates of up to 60.77%. The relationship between the ultrasonic sound speed and the increasing fluidity could be deduced as a negative correlation. The water absorption was negatively correlated with the compressive strength. The concrete with a slump flow of 12.35 and 12.5 cm reached the maximum compressive strength, which had the lowest water absorption, and demonstrated internal homogeneity. The optimum slump flow was 12.35 and 12.5 cm. With the slump flow of 12.5 cm, the corresponding CV was the lowest, showing the optimum SC's dispersion. Through TG, XRD, and SEM analyses, it was verified that the addition of 0.6% WRA promoted the hydration of cement. In addition, SC increased the hydration products. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
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