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1.
Anal Chim Acta ; 1190: 339264, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34857144

RESUMO

A surface acoustic wave (SAW) gas sensor with an Au/TiO2/poly(3,4-ethylenedioxythiophene) (PEDOT, which is a conductive polymer with photoelectric conversion function) sensing film was constructed for the quantitative detection of water vapor and CO2. The Au/TiO2/PEDOT sensing film was assembled on the delayed region of the 204 MHz SAW delay line, which was used as the base device for the gas sensor. The center frequency of the sensor decreases with an increase in relative humidity (RH), and the center frequency increases with increasing CO2 concentration, so that not only can the two gases be identified, but quantitative analysis can also be performed. The SAW sensor has a response range of 5%-90% for RH and a response range of 500-2000 ppm for CO2 gas. The shifts in center frequency varied linearly with the concentrations, giving rise to the sensitivities of -0.0068 and -0.1880 kHz %-1 for RH and ∼0.003 kHz ppm-1 CO2. The response/recovery time is 9 s/9.2 s for 700 ppm CO2 and 15 s/14 s for 70% RH. The experimental results show that the SAW sensor offers excellent selectivity, wide response range, rapid response, and good stability and repeatability. The mechanism of humidity and CO2 sensing is attributed to the hydrophilic porous structure of the Au/TiO2/PEDOT sensing film, and also to the reversible variation of its viscoelasticity under illumination conditions. The sensor, combined with the communication function of its own SAW device, has several prospective applications in the monitoring of atmospheric conditions.


Assuntos
Dióxido de Carbono , Som , Compostos Bicíclicos Heterocíclicos com Pontes , Umidade , Polímeros , Titânio
2.
Appl Ergon ; 98: 103603, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34638037

RESUMO

Auditory comfort evaluations are garnering increased attention in engineering and particularly in the context of air transportation. Being able to produce sound environments corresponding to various flight conditions in aircraft mock-ups would be a valuable tool to investigate acoustic comfort inside aircrafts in controlled environments. Before using such mock-ups, they must be developed and validated in physical and perceptual terms. This paper provides a perceptual validation of sound environment reproduction inside aircraft mock-up. To provide a faithfully reproduced sound environment, time, frequency and spatial characteristics should be preserved. Physical sound field reproduction approaches for spatial sound reproduction are required while properly preserving localization cues at the listener's ears to recreate a realistic and immersing sound environment. We report a perceptual validation of a sound field reproduction system developed in an aircraft mock-up based on multichannel least-square methods and equalization. Twenty participants evaluated reproduced sound environments relative to a reference sound environment in an aircraft cabin mock-up equipped with a 41-actuator multichannel sound reproduction system. Results indicate that the preferred reproduction corresponds to the best physical reconstruction of the sound environment.


Assuntos
Aeronaves , Som , Atenção , Sinais (Psicologia) , Humanos , Reprodução
3.
Appl Ergon ; 99: 103609, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34700191

RESUMO

When more than one audible alarm is heard simultaneously, discrimination may be compromised. This experiment compares near-simultaneous clinical alarms in two styles, the first are the tonal 'melodies' from the 2012/2006 version of a global medical device safety standard (IEC 60601-1-8) and the second are the auditory-icon-style recommended in the 2020 version of the same standard. Sixty-six participants were required to identify the meaning and priority of four different clinical alarms for one of the two styles of alarm (between-subjects). Alarms sounded both singly and in pairs (within-subjects). Results showed that the auditory icon alarms outperformed the tonal alarms on all measures except one, both for overall accuracy (recognizing both priority and function) and for partial accuracy (recognizing priority or function but not both). The results add to the growing body of evidence supporting the use of auditory icon alarms in clinical environments.


Assuntos
Alarmes Clínicos , Humanos , Monitorização Fisiológica , Som
4.
J Neurosurg Anesthesiol ; 34(1): e63-e67, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32568817

RESUMO

OBJECTIVE: Two-photon laser-scanning microscopy allows for the monitoring of all brain neurons with single-cell and single-action potential accuracy. This study aimed to investigate the neural responses of the primary auditory cortex to sound stimuli in awake and propofol-anesthetized mice using 2-photon laser-scanning microscopy. METHODS: Twelve healthy adult male C57BL/6 mice were used in the present study. In each mouse, the scalp was removed over the entire dorsal skull, and the right primary auditory cortex (A1) located. The test stimulus, used in the awake and propofol-induced anesthetic state, was a group of tones with a random combination of 3 sound intensities and 8 sound frequencies. The calcium indicator GCaMP6s was virally expressed in cortical neurons and neuronal activity was recorded using 2-photon imaging. RESULTS: Calcium responses to sound stimuli in two thirds of the neuronal population of the A1 layer were significantly inhibited by propofol anesthesia. In a single neuron, the calcium responses were also inhibited by propofol anesthesia. In the waking state, △F/F (where F is the time series of fluorescence intensity) of all single neurons was significantly higher than that in the propofol-induced anesthetic state (n=669, P<0.001). Finally, in one example session and averaged across different fields of views (n=6 sessions), the response events to sound stimuli were also inhibited by propofol anesthesia. CONCLUSION: Anesthetic doses of propofol inhibited calcium transients and neuronal activity in the primary auditory cortex of mice.


Assuntos
Córtex Auditivo , Propofol , Estimulação Acústica , Animais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Propofol/farmacologia , Som
5.
Sci Total Environ ; 802: 149869, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34461470

RESUMO

The ratio of the perceived extent of natural sounds to the perceived extent of traffic noise in the environment has been demonstrated to be important for soundscapes, whereas research on the influence of human sounds has been limited. To examine this influence, this study proposes a human sound-based index named the red soundscape index (RSI), which is defined as the ratio of the perceived extent of human sounds to the perceived extent of other sounds. Sound pressure levels and crowd density were collected at 41 sites in 9 urban parks, and pedestrian streets in Harbin, China, and the perceived extent of various sounds was investigated by a questionnaire survey. The results confirmed a significant positive correlation between crowd density and RSI, and the A-weighted sound pressure level increased linearly with increasing RSIn (the ratio of human sounds to natural sounds) and decreased with increasing RSIt (the ratio of human sounds to traffic noises). Interestingly, the overall soundscape assessment linearly decreases with the increase in RSIn in the range of (0.8-1.5). The relationship with RSIt first shows an increase and then a decrease in a parabolic form, in which the axis of symmetry is RSIt = 2. Correspondingly, urban open spaces can be divided into three categories based on the variation trend, and different types have significant differences in overall soundscape assessment, pleasantness, and calmness. Among these, pleasantness is the highest in the sites of natural sound predominance perception. At the same time, this factor becomes the lowest in the sites of human sound predominance perception and middle in the site of balanced perception. Consequently, RSI is expected to be useful in soundscape prediction in urban open spaces.


Assuntos
Ruído , Som , China , Aglomeração , Humanos , Parques Recreativos
6.
Ultrasonics ; 118: 106564, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34530395

RESUMO

Tissue-Mimicking Material (TMM) is defined on IEC International Standards and applied in assessing ultrasonic diagnostic and therapeutic equipment's basic safety and essential performance. One of the TMM that fits IEC standards specification has its recipe described at IEC 60601-2-37, and it is fabricated using glycerol (11.21 %), deionized water (82.95%), benzalkonium chloride (0.47 %), silicon carbide (0.53 %), aluminum oxide 0.3 µm (0.88%), aluminum oxide 3.0 µm (0.94 %), and agar (3.08 %). Glycerol is the component responsible for adjusting the TMM's speed of sound. Moreover, it is recommended to store TMM in a closed container immersed in a mixture of water (88.1 %)/glycerol (11.9 %) to prevent it from drying out and avoiding air contact. The literature points out TMM measurements underwater can alter the speed of sound property as TMM tends to lose glycerol. Herein, the authors proposed to assess the viability of measuring the TMM speed of sound in the water/glycerol maintenance solution. First, the authors characterized the maintenance solution's speed of sound for a temperature range of 20 °C to 45 °C. Then, the group velocity of a set of TMM was measured underwater and in the maintenance solution for the same temperature range. The respective group velocity expanded uncertainty was calculated. The results indicate it is feasible to measure TMM in the maintenance solution, achieving group velocity values with no statistical difference from the ones measured underwater in the temperature range of 20 °C to 40 °C.


Assuntos
Materiais Biomiméticos , Imagens de Fantasmas/normas , Som , Terapia por Ultrassom/instrumentação , Ultrassonografia/instrumentação , Óxido de Alumínio , Compostos de Benzalcônio , Calibragem , Compostos Inorgânicos de Carbono , Segurança de Equipamentos , Glicerol , Compostos de Silício , Temperatura , Água
7.
Artigo em Russo | MEDLINE | ID: mdl-34932294

RESUMO

Tinnitus is one of the most common otological symptoms and can be defined as the conscious perception of sound lasting more than 5 minutes in the absence of an external auditory stimulus. Based on the review of articles, a comparative analysis of modern methods of diagnosis and treatment of tinnitus was carried out in order to substantiate the most effective and promising algorithms for providing care to patients. Diagnosis of tinnitus includes taking anamnesis, assessing the severity of tinnitus using questionnaires, otoscopy, hearing examination, and performing additional tests. In case of secondary murmur, etiotropic therapy should be started as soon as possible to prevent hearing loss and other complications. For primary noise, the most effective treatments are cognitive-behavioral therapy, tinnitus maskers and sound therapy, transcutaneous electrical stimulation, and biofeedback. Magnetic stimulation, invasive neuromodulation, drug therapy have a lower level of effectiveness and evidence base.


Assuntos
Zumbido , Estimulação Elétrica Nervosa Transcutânea , Estimulação Acústica , Humanos , Som , Zumbido/diagnóstico , Zumbido/terapia , Resultado do Tratamento
8.
PLoS One ; 16(12): e0261496, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34937069

RESUMO

Clinical studies on the efficacy of sonic toothbrushes show inconsistent results, most studies have been conducted without sufficient supervision of appropriate toothbrush usage. Aims of the explorative clinical trial were therefore to investigate whether the usage of an activated sonic toothbrush reduces plaque more effectively than an inactivated one used as a manual toothbrush, and to which extent the correct use of such toothbrush plays a role in its efficacy. The clinical trial was designed as a video-controlled interventional study. Thirty participants (mean (±SD) age 22.9 (±2.5) years) were included, areas of interest were the buccal surfaces of the upper premolars and the first molar (partial mouth recording). Toothbrushing was performed without toothpaste in a single brushing exercise under four different conditions: switched off, habitually used as manual toothbrush, no instruction; switched on, habitually used as powered toothbrush, no instruction; switched off, used as manual toothbrush, instruction in the Modified Bass Technique; switched on, used as powered toothbrush, instruction in a specific technique for sonic toothbrushes. Brushing performance was controlled by videotaping, plaque was assessed at baseline (after 4 days without toothbrushing) using the Rustogi modified Navy-Plaque-Index and planimetry. Main study results were that plaque decreased distinctly after habitual brushing regardless of using the sonic brush in ON or OFF mode (p for all comparisons < 0.001). After instruction, participants were able to use the sonic brush in ON mode as intended, with only minor impact on efficacy. Using the toothbrush in OFF mode with the Modified Bass Technique was significantly less effective than all other conditions (p for all comparisons < 0.001). Under the conditions used, the sonic toothbrush was not more effective when switched on than when switched off, and there was no evidence that the correct use of the toothbrush was more effective than the habitual use.


Assuntos
Índice de Placa Dentária , Gengivite , Escovação Dentária/instrumentação , Adulto , Feminino , Gengivite/diagnóstico , Gengivite/prevenção & controle , Humanos , Masculino , Estudos Prospectivos , Som , Escovação Dentária/métodos , Gravação em Vídeo , Adulto Jovem
9.
Nat Commun ; 12(1): 7278, 2021 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-34907158

RESUMO

Perception is thought to be shaped by the environments for which organisms are optimized. These influences are difficult to test in biological organisms but may be revealed by machine perceptual systems optimized under different conditions. We investigated environmental and physiological influences on pitch perception, whose properties are commonly linked to peripheral neural coding limits. We first trained artificial neural networks to estimate fundamental frequency from biologically faithful cochlear representations of natural sounds. The best-performing networks replicated many characteristics of human pitch judgments. To probe the origins of these characteristics, we then optimized networks given altered cochleae or sound statistics. Human-like behavior emerged only when cochleae had high temporal fidelity and when models were optimized for naturalistic sounds. The results suggest pitch perception is critically shaped by the constraints of natural environments in addition to those of the cochlea, illustrating the use of artificial neural networks to reveal underpinnings of behavior.


Assuntos
Redes Neurais de Computação , Percepção da Altura Sonora/fisiologia , Estimulação Acústica , Cóclea/fisiologia , Humanos , Música , Ruído , Discriminação da Altura Tonal/fisiologia , Som
10.
Sensors (Basel) ; 21(24)2021 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-34960277

RESUMO

One of the axioms of structural health monitoring states that the severity of damage assessment can only be done in a learning mode under the supervision of an expert. Therefore, a numerical analysis was conducted to gain knowledge regarding the influence of the damage size on the propagation of elastic waves in a honeycomb sandwich composite panel. Core-skin debonding was considered as damage. For this purpose, a panel was modelled taking into account the real geometry of the honeycomb core using the time-domain spectral element method and two-dimensional elements. The presented model was compared with the homogenized model of the honeycomb core and validated in the experimental investigation. The result of the parametric study is a function of the influence of damage on the amplitude and energy of propagating waves.


Assuntos
Som
11.
Sensors (Basel) ; 21(24)2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34960475

RESUMO

Weakly labeled sound event detection (WSED) is an important task as it can facilitate the data collection efforts before constructing a strongly labeled sound event dataset. Recent high performance in deep learning-based WSED's exploited using a segmentation mask for detecting the target feature map. However, achieving accurate detection performance was limited in real streaming audio due to the following reasons. First, the convolutional neural networks (CNN) employed in the segmentation mask extraction process do not appropriately highlight the importance of feature as the feature is extracted without pooling operations, and, concurrently, a small size kernel forces the receptive field small, making it difficult to learn various patterns. Second, as feature maps are obtained in an end-to-end fashion, the WSED model would be weak to unknown contents in the wild. These limitations would lead to generating undesired feature maps, such as noise in the unseen environment. This paper addresses these issues by constructing a more efficient model by employing a gated linear unit (GLU) and dilated convolution to improve the problems of de-emphasizing importance and lack of receptive field. In addition, this paper proposes pseudo-label-based learning for classifying target contents and unknown contents by adding 'noise label' and 'noise loss' so that unknown contents can be separated as much as possible through the noise label. The experiment is performed by mixing DCASE 2018 task1 acoustic scene data and task2 sound event data. The experimental results show that the proposed SED model achieves the best F1 performance with 59.7% at 0 SNR, 64.5% at 10 SNR, and 65.9% at 20 SNR. These results represent an improvement of 17.7%, 16.9%, and 16.5%, respectively, over the baseline.


Assuntos
Redes Neurais de Computação , Ruído , Acústica , Audição , Som
13.
Sensors (Basel) ; 21(22)2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34833701

RESUMO

Imaging sonar systems are widely used for monitoring fish behavior in turbid or low ambient light waters. For analyzing fish behavior in sonar images, fish segmentation is often required. In this paper, Mask R-CNN is adopted for segmenting fish in sonar images. Sonar images acquired from different shallow waters can be quite different in the contrast between fish and the background. That difference can make Mask R-CNN trained on examples collected from one fish farm ineffective to fish segmentation for the other fish farms. In this paper, a preprocessing convolutional neural network (PreCNN) is proposed to provide "standardized" feature maps for Mask R-CNN and to ease applying Mask R-CNN trained for one fish farm to the others. PreCNN aims at decoupling learning of fish instances from learning of fish-cultured environments. PreCNN is a semantic segmentation network and integrated with conditional random fields. PreCNN can utilize successive sonar images and can be trained by semi-supervised learning to make use of unlabeled information. Experimental results have shown that Mask R-CNN on the output of PreCNN is more accurate than Mask R-CNN directly on sonar images. Applying Mask R-CNN plus PreCNN trained for one fish farm to new fish farms is also more effective.


Assuntos
Processamento de Imagem Assistida por Computador , Redes Neurais de Computação , Som , Manejo de Espécimes , Aprendizado de Máquina Supervisionado
14.
Sensors (Basel) ; 21(22)2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34833554

RESUMO

Due to the strong absorption and attenuation of electromagnetic waves by water, radio communications and global positioning systems are lacking in the deep-sea environment. Therefore, underwater long-distance communications, positioning, detection and other functions depend on acoustic technology. In order to realize the above functions, the acoustic system of the Fendouzhe human occupied vehicle (HOV) is composed of eight kinds of sonars and sensors, which is one of the core systems of manned submersible. Based on the Jiaolong/Shenhai Yongshi HOVs, the acoustic system of the Fendouzhe HOV has been developed. Compared with the previous technology, there are many technical improvements and innovations: 10,000-m underwater acoustic communication, 10,000-m underwater acoustic positioning, multi-beam forward-looking imaging sonar, an integrated navigation system, etc. This study introduces the structure of the acoustic system of the Fendouzhe HOV and the technical improvements compared with the Jiaolong/Shenhai Yongshi HOVs. The results of the acoustic system are illustrated by the 10,000-m sea trails in the Mariana Trench from October to December 2020.


Assuntos
Acústica , Som , Humanos , Água
15.
Sensors (Basel) ; 21(21)2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34770267

RESUMO

For high-resolution side scan sonar images, accurate and fast segmentation of sonar images is crucial for underwater target detection and recognition. However, due to the characteristics of low signal-to-noise ratio (SNR) and complex environmental noise of sonar, the existing methods with high accuracy and good robustness are mostly iterative methods with high complexity and poor real-time performance. For this purpose, a region growing based segmentation using the likelihood ratio testing method (RGLT) is proposed. This method obtains the seed points in the highlight and the shadow regions by likelihood ratio testing based on the statistical probability distribution and then grows them according to the similarity criterion. The growth avoids the processing of the seabed reverberation regions, which account for the largest proportion of sonar images, thus greatly reducing segmentation time and improving segmentation accuracy. In addition, a pre-processing filtering method called standard deviation filtering (STDF) is proposed to improve the SNR and remove the speckle noise. Experiments were conducted on three sonar databases, which showed that RGLT has significantly improved quantitative metrics such as accuracy, speed, and segmentation visual effects. The average accuracy and running times of the proposed segmentation method for 100 × 400 images are separately 95.90% and 0.44 s.


Assuntos
Algoritmos , Processamento de Imagem Assistida por Computador , Funções Verossimilhança , Razão Sinal-Ruído , Som
16.
Sensors (Basel) ; 21(21)2021 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-34770350

RESUMO

In the field of underwater vision, image matching between the main two sensors (sonar and optical camera) has always been a challenging problem. The independent imaging mechanism of the two determines the modalities of the image, and the local features of the images under various modalities are significantly different, which makes the general matching method based on the optical image invalid. In order to make full use of underwater acoustic and optical images, and promote the development of multisensor information fusion (MSIF) technology, this letter proposes to apply an image attribute transfer algorithm and advanced local feature descriptor to solve the problem of underwater acousto-optic image matching. We utilize real and simulated underwater images for testing; experimental results show that our proposed method could effectively preprocess these multimodal images to obtain an accurate matching result, thus providing a new solution for the underwater multisensor image matching task.


Assuntos
Algoritmos , Processamento de Imagem Assistida por Computador , Acústica , Som , Visão Ocular
17.
Sensors (Basel) ; 21(21)2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34770495

RESUMO

Based on the principle of underwater transducers, an ultrasonic four-laminated transducer with a frequency of 1 MHz was proposed to solve the problem of large energy attenuation when ultrasonic waves propagate in viscoelastic media. First, this study targeted solid rocket propellant as the research object, and the energy attenuation characteristics of ultrasonic waves propagating in viscoelastic media were analyzed through the derivation of the wave equation. Second, the structure of a four-laminated transducer with a frequency of 1 MHz was designed, and the resonance frequency was obtained by a graphical method. The sound field simulation and experimental results showed that the gain of the four-laminated transducer was 15 dB higher than that of the single-wafer transducer. An ultrasonic feature scanning system was built to complete the qualitative and quantitative detection of the smallest artificial hole (ϕ2 mm × 10 mm). Finally, two different natural defects were scanned, and the results were compared with those obtained using an industrial computed tomography detection system. The results showed that the ultrasonic method was more accurate in characterizing two natural defects. The primary cause was that the industrial CT was not sensitive to defects parallel to the incident direction of the ray. Therefore, this study not only achieved the qualitative and quantitative nondestructive testing of solid rocket propellants, but also provides an important reference for other viscoelastic components.


Assuntos
Transdutores , Ultrassom , Simulação por Computador , Som , Vibração
18.
Sensors (Basel) ; 21(21)2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34770635

RESUMO

Distinguishing between a dangerous audio event like a gun firing and other non-life-threatening events, such as a plastic bag bursting, can mean the difference between life and death and, therefore, the necessary and unnecessary deployment of public safety personnel. Sounds generated by plastic bag explosions are often confused with real gunshot sounds, by either humans or computer algorithms. As a case study, the research reported in this paper offers insight into sounds of plastic bag explosions and gunshots. An experimental study in this research reveals that a deep learning-based classification model trained with a popular urban sound dataset containing gunshot sounds cannot distinguish plastic bag pop sounds from gunshot sounds. This study further shows that the same deep learning model, if trained with a dataset containing plastic pop sounds, can effectively detect the non-life-threatening sounds. For this purpose, first, a collection of plastic bag-popping sounds was recorded in different environments with varying parameters, such as plastic bag size and distance from the recording microphones. The audio clips' duration ranged from 400 ms to 600 ms. This collection of data was then used, together with a gunshot sound dataset, to train a classification model based on a convolutional neural network (CNN) to differentiate life-threatening gunshot events from non-life-threatening plastic bag explosion events. A comparison between two feature extraction methods, the Mel-frequency cepstral coefficients (MFCC) and Mel-spectrograms, was also done. Experimental studies conducted in this research show that once the plastic bag pop sounds are injected into model training, the CNN classification model performs well in distinguishing actual gunshot sounds from plastic bag sounds.


Assuntos
Algoritmos , Redes Neurais de Computação , Coleta de Dados , Humanos , Som
19.
Sensors (Basel) ; 21(21)2021 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-34770658

RESUMO

The successful development of a system realizing color sonification would enable auditory representation of the visual environment. The primary beneficiary of such a system would be people that cannot directly access visual information-the visually impaired community. Despite the plethora of sensory substitution devices, developing systems that provide intuitive color sonification remains a challenge. This paper presents design considerations, development, and the usability audit of a sensory substitution device that converts spatial color information into soundscapes. The implemented wearable system uses a dedicated color space and continuously generates natural, spatialized sounds based on the information acquired from a camera. We developed two head-mounted prototype devices and two graphical user interface (GUI) versions. The first GUI is dedicated to researchers, and the second has been designed to be easily accessible for visually impaired persons. Finally, we ran fundamental usability tests to evaluate the new spatial color sonification algorithm and to compare the two prototypes. Furthermore, we propose recommendations for the development of the next iteration of the system.


Assuntos
Pessoas com Deficiência Visual , Dispositivos Eletrônicos Vestíveis , Algoritmos , Humanos , Som
20.
Sensors (Basel) ; 21(21)2021 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-34770696

RESUMO

The computer modelling of condition monitoring sensors can aide in their development, improve their performance, and allow for the analysis of sensor impact on component operation. This article details the development of a COMSOL model for a guided wave-based temperature monitoring system, with a view to using the technology in the future for the temperature monitoring of nozzle guide vanes, found in the hot section of aeroengines. The model is based on an experimental test system that acts as a method of validation for the model. Piezoelectric wedge transducers were used to excite the S0 Lamb wave mode in an aluminium plate, which was temperature controlled using a hot plate. Time of flight measurements were carried out in MATLAB and used to calculate group velocity. The results were compared to theoretical wave velocities extracted from dispersion curves. The assembly and validation of such a model can aide in the future development of guided wave based sensor systems, and the methods provided can act as a guide for building similar COMSOL models. The results show that the model is in good agreement with the experimental equivalent, which is also in line with theoretical predictions.


Assuntos
Som , Transdutores , Animais , Simulação por Computador , Ovinos , Temperatura
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