Sound Profile Research Articles

Sizing Small Crack-like Flaws through Non-ideal Part Surface Using Ultrasonic Measurement Model

ABSTRACTTo accurately size small crack-like flaws in components with non-ideal surface conditions, such as curvature, roughness, and coating, we developed a flaw sizing method based on an ultrasonic measurement model. First, the effects of surface curvature on the sound beam profile, as well as the effects of surface coating and roughness on the wave energy are investigated theoretically and experimentally. Then, correction methods for curvature, roughness, and coating are introduced into the ultrasonic measurement model, and the flaw response in components with different surface conditions is predicted. Lastly, by accounting for the effects of surface conditions, a set of model-based flaw sizing curves is generated for predicting the equivalent size of crack-like flaws. These model-based curves can guide the setting of system parameters and improve the flaw sizing accuracy. Experiments are then conducted to verify the effectiveness of the proposed method. This work demonstrates the utility of the ultrasonic method for measuring the equivalent flaw size in practical applications.

Formation of the broadband biosonar beam of dolphins: Melon-focusing hypothesis not correct

In 1974, Norris and Harvey measured the sound velocity profile of the melon of a just deceased bottlenose dolphin and found a low-velocity core in the melon with the velocity increasing towards the surface. This was the genesis of the “melon focusing” hypothesis in the formation of the biosonar beam. Aroyan solved the wave equation for a signal produced at the nasal plug using a finite difference approach and found that the skull was responsible for the biosonar beam. Aroyan’s results were never taken seriously and the notion that the melon was mainly responsible for the biosonar beam continues to this day. We used a finite element approach to solve the wave equation for a broadband signal generated at the phonic lips. CT scan data were used to provide a map of the acoustic impedance of the dolphin’s head and our results compared well with different measurements made around the dolphin’s head and in the far field. Our findings also showed that the skull and air sacs are the most influential structures in the formation of the biosonar beam and the melon was responsible for directing the axis of the beam. Our results should put to rest the “melon-focusing” hypothesis.

Гидроакустическое исследование макроскопической донной растительности в заповедной морской акватории у мыса Мартьян (Крым, Чёрное море)

В заповедной акватории у мыса Мартьян (Южный берег Крыма) выполнено обследование макроскопической донной растительности (МДР) с применением гидроботанических (контактных) и гидроакустических (дистанционных) методов. Показана принципиальная возможность и эффективность использования мобильного акустического комплекса на базе эхолота SeaCharter 480 DF и специализированного программного обеспечения WaveLens для детектирования и установления общей характеристики МДР, а также для выявления границ её обитания, проективного покрытия, высоты растительного покрова и пр. Модифицирована и апробирована методика, включая программное обеспечение, для автоматического определения высоты зарослей МДР по профилю обратного рассеяния звука. С помощью дистанционных методов показано, что распределение сублиторальной МДР вдоль берега характеризуется поясностью, причём нижняя граница распространения ограничена изобатами 10–12 м, что соответствует результатам, полученным контактными методами. Общая площадь зарослей МДР — около 0,39 км²; максимальные значения проективного покрытия, достигающие 95–97 % на глубинах 2–3 м, к нижней границе снижаются до 50–70 %. Установлено, что общие запасы сублиторальной МДР составляют до 1431,3 т, из которых 99,6 % приходится на сообщества Cystoseira. Отмечено, что цистозиры (Cystoseira barbata (Stackhouse) C. Agardh, 1820 и Cystoseira crinita Duby, 1830) и взморники (Zostera marina Linnaeus, 1753 и Zostera noltei Hornemann, 1832), доминирующие в растительных сообществах исследованного участка, являются сильными звукорассеивателями вследствие значительной разности акустического сопротивления (импеданса) воздуха, содержащегося в органах и тканях, и воды, что существенно повышает результативность детектирования и описания МДР. За нижней границей МДР, на глубинах до 32 м, зафиксированы неопознанные придонные акустические объекты в виде одиночных или групповых целей высотой до 2–4 м. Вероятно, их природа различна и обусловлена наличием в исследованном районе метановых сипов либо плотных скоплений рыбы. Отмечено, что проведение количественного исследования МДР с использованием гидроакустических методов снижает негативное трансформирующее воздействие на объект изучения: данная методика не предполагает значительного изъятия МДР, что особенно важно для соблюдения условий заповедного режима в границах особо охраняемых природных территорий (ООПТ). Полученные результаты наглядно показали эффективность совместного применения контактных и дистанционных методов. Предложено в дальнейшем использовать гидроакустические методы для мониторинга МДР, картирования растительного покрова и определения запасов макрофитов заповедной прибрежно-морской акватории у м. Мартьян и других аквальных ООПТ.

Determining the Variability of the Territorial Sea Baseline on the Example of Waterbody Adjacent to the Municipal Beach in Gdynia

The purpose of this publication is to analyze the spatial and temporal variability of the territorial sea baseline in sand bottom waterbodies, which were determined twice, in 2016 and 2018, by the Real Time Kinematic (RTK) method. This involves direct measurement of sea bottom coordinates on planned hydrographic sounding profiles using a Global Navigation Satellite System (GNSS) receiver mounted on a pole. The data were the basis for creating Digital Terrain Models (DTM), which were then used to determine the baseline for both measurement campaigns. Subsequently, terrain surface models were compared to determine bathymetry changes in the area under analysis, and an assessment was made of the baseline spatial position change over the previous two years. The measurements have shown considerable spatial and temporal variability of the baseline course along a short section of sandy beach. The territorial sea baseline was very unstable; in some places, it moved by even 20–25 m, landwards and seawards. Therefore, one can suppose that these changes are periodic, and one can conclude that the reliability of the baseline measurements can decrease quite quickly.

Assessment of the Steering Precision of a Hydrographic Unmanned Surface Vessel (USV) along Sounding Profiles Using a Low-Cost Multi-Global Navigation Satellite System (GNSS) Receiver Supported Autopilot.

The performance of bathymetric measurements by traditional methods (using manned vessels) in ultra-shallow waters, i.e., lakes, rivers, and sea beaches with a depth of less than 1 m, is often difficult or, in many cases, impossible due to problems related to safe vessel maneuvering. For this reason, the use of shallow draft hydrographic Unmanned Surface Vessels (USV) appears to provide a promising alternative method for performing such bathymetric measurements. This article describes the modernisation of a USV to switch from manual to automatic mode, and presents a preliminary study aimed at assessing the suitability of a popular autopilot commonly used in Unmanned Aerial Vehicles (UAV), and a low-cost multi-Global Navigation Satellite System (GNSS) receiver cooperating with it, for performing bathymetric measurements in automated mode, which involves independent movement along a specified route (hydrographic sounding profiles). The cross track error (XTE) variable, i.e., the distance determined between a USV’s position and the sounding profile, measured transversely to the course, was adopted as the measure of automatic control precision. Moreover, the XTE value was statistically assessed in the publication.

Electromagnetic studies of Zvizdal-Zaliska and Brusyliv fault zones of the Ukrainian shield

Spatial-temporal distribution pattern of geomagnetic variations and electric field in the western part of the Ukrainian shield has been obtained as a result of experimental studies carried out by the methods of deep magnetotelluric sounding and magnetovariational profiling in 2018 along two profiles (15 points). It makes possible to estimate the value of electroconductivity and geoelectric structure of the section along the vertical and horizontal directions. Processing has been conducted with the help of modern software system PRC-MTMV that guarantees joint noise immunity of evaluation of impedance and induction parameters of synchronous МТ/МВ-records. Tipper appraisals have been obtained for the periods of geomagnetic variations from 50 to 3400 s, the curves of apparent resistance and phases of impedance from 20 to 10000 s. The principal result of high quality interpretation of geoelectric studies is revealing of high electro-conductivity anomalies (4 surface ones, 1 subsurface) in the Earth crust with complex system of faults in jointing zone of the Podolia and Rossinsky megablocks. Anomalies are characterized by different electroconductivity, the depth of occurrence and shape. Appraisals obtained with different approaches to formal interpretation of magnetotelluric sounding agree with regional three-dimensional geoelectric model of the western part of the Ukrainian shield and add to the concept on debatable deep structure. Surface anomalies of electroconductivity have been discovered: 1) in the central part of Zvizdal-Zalessky fault zone, 2) between the Pogrebynsky and the Kocherov faults, 3) along the Velykoerchyk and 4) Ulashev faults. Their nature is explained by heightened content of graphite and by ore formation confined to tectono-metasomatic zones. Deep anomaly of electroconductivity has been allocated with its surface projection spatially coinsiding with the area of cross-section of the Brussilov and the Nemyrov fault zones (and mineraginetic zones of the same name). Its upper edge deepens eastward from Zvizdal-Zalessky fault zone. High electroconductivity anomalies are spatially attached to tectonic fault zones and the zones of metasomatic alterations. Their territorial arrangement corresponds to metallogenic ore zones. Therefore they can be used as geoelectric criteria for the search of ore manifestations.

Effects of Phantom Electrode Stimulation on Vocal Production in Cochlear Implant Users.

Cochlear implant (CI) users suffer from a range of speech impairments, such as stuttering and vocal control of pitch and intensity. Though little research has focused on the role of auditory feedback in the speech of CI users, these speech impairments could be due in part to limited access to low-frequency cues inherent in CI-mediated listening. Phantom electrode stimulation (PES) represents a novel application of current steering that extends access to low frequencies for CI recipients. It is important to note that PES transmits frequencies below 300 Hz, whereas Baseline does not. The objective of this study was to explore the effects of PES on multiple frequency-related characteristics of voice production. Eight postlingually deafened, adult Advanced Bionics CI users underwent a series of vocal production tests including Tone Repetition, Vowel Sound Production, Passage Reading, and Picture Description. Participants completed all of these tests twice: once with PES and once using their program used for everyday listening (Baseline). An additional test, Automatic Modulation, was included to measure acute effects of PES and was completed only once. This test involved switching between PES and Baseline at specific time intervals in real time as participants read a series of short sentences. Finally, a subjective Vocal Effort measurement was also included. In Tone Repetition, the fundamental frequencies (F0) of tones produced using PES and the size of musical intervals produced using PES were significantly more accurate (closer to the target) compared with Baseline in specific gender, target tone range, and target tone type testing conditions. In the Vowel Sound Production task, vowel formant profiles produced using PES were closer to that of the general population compared with those produced using Baseline. The Passage Reading and Picture Description task results suggest that PES reduces measures of pitch variability (F0 standard deviation and range) in natural speech production. No significant results were found in comparisons of PES and Baseline in the Automatic Modulation task nor in the Vocal Effort task. The findings of this study suggest that usage of PES increases accuracy of pitch matching in repeated sung tones and frequency intervals, possibly due to more accurate F0 representation. The results also suggest that PES partially normalizes the vowel formant profiles of select vowel sounds. PES seems to decrease pitch variability of natural speech and appears to have limited acute effects on natural speech production, though this finding may be due in part to paradigm limitations. On average, subjective ratings of vocal effort were unaffected by the usage of PES versus Baseline.

Detection of Severity of Chronic Cough in Elders and Children using Machine Learning

Cough is a prevalent symptom of many illnesses of the respiratory system. The assessment of its intensity and event frequency could provide useful clinical data in the assessment of chronic cough patients .The MEMS vibration sensor is placed in neck either as batches or robes. The band-like filter patch was put on the body of the patient. Sensor is driven by batteries that allow patient mobility and connect to a smartphone phone. Smartphone transmits information to a cloud-based health platform that provides additional information and alerts medical staff. The machine learning algorithms collect and analyze the sound of the coughs to personalize it to the user based on its pitch and sound profile, which is unique to each person based on the size and capacity of his or her lungs. When coughing indicates an impending attack, the device transmits a message to the dedicated cloud-based software via the nearest cellular communications tower. A text message is then automatically sent to one or more caretakers ' smartphones, alerting them to early indications of an assault by the client. If various caregivers are present, the first person to react may use the smartphone to give a response text message to all others, notifying them of being with or on the manner to the patient. The doctors could use recordings of coughing to help diagnose an illness. The device issues an alert only to caregivers, because sending an audio file would consume a significant amount of battery power. However, when the wearable sensor batch is recharging, it could be provisioned to forward sound files to the patient's doctor.

Can the diffuseness of sound sources in an auditory scene alter speech perception?

When amplification is used, sound sources are often presented over multiple loudspeakers, which can alter their timbre, and introduce comb-filtering effects. Increasing the diffuseness of a sound by presenting it over spatially separated loudspeakers might affect the listeners' ability to form a coherent auditory image of it, alter its perceived spatial position, and may even affect the extent to which it competes for the listener's attention. In addition, it can lead to comb-filtering effects that can alter the spectral profiles of sounds arriving at the ears. It is important to understand how these changes affect speech perception. In this study, young adults were asked to repeat nonsense sentences presented in either noise, babble, or speech. Participants were divided into two groups: (1) A Compact-Target Timbre group where the target sentences were presented over a single loudspeaker (compact target), while the masker was either presented over three loudspeakers (diffuse) or over a single loudspeaker (compact); (2) A Diffuse-Target Timbre group, where the target sentences were diffuse while the masker was either compact or diffuse. Timbre had no significant effect in the absence of a timbre contrast between target and masker. However, when there was a timbre contrast, the signal-to-noise ratios needed for 50% correct recognition of the target speech were higher (worse) when the masker was compact, and lower (better) when the target was compact. These results were consistent with the expected effects from comb filtering, and could also reflect a tendency for attention to be drawn towards compact sound sources.

An Improved Data Detection Method for Mesoscale Vortex Flow Field Based on Optimum Launching Environment of Major Launch Weapons

As a common ocean phenomenon, mesoscale eddies have strong internal flow velocity and large vertical depth scale, which affect the horizontal non-uniform variation of sound velocity profile. Mesoscale eddies affect the use of underwater sonar. While improving the concealment of submarine navigation, they may cause serious interference to the launch and guidance of missile weapon. Geometric methods can identify more mesoscale vortices with relatively small scales, but there are some missing and wrong judgements. Based on the current mainstream algorithms, this paper improves and improves the mesoscale eddy recognition and information extraction algorithm by improving the quadrant restriction and restricting the boundary conditions, so as to reduce the rate of missed judgment and false judgment.

Pressure and Composition Effects on Sound Velocity and Density of Core‐Forming Liquids: Implication to Core Compositions of Terrestrial Planets

AbstractA compositional variety of planetary cores provides insight into their core/mantle evolution and chemistry in the early solar system. To infer core composition from geophysical data, a precise knowledge of elastic properties of core‐forming materials is of prime importance. Here, we measure the sound velocity and density of liquid Fe‐Ni‐S (17 and 30 at% S) and Fe‐Ni‐Si (29 and 38 at% Si) at high pressures and report the effects of pressure and composition on these properties. Our data show that the addition of sulfur to iron substantially reduces the sound velocity of the alloy and the bulk modulus in the conditions of this study, while adding silicon to iron increases its sound velocity but has almost no effect on the bulk modulus. Based on the obtained elastic properties combined with geodesy data, S or Si content in the core is estimated to 4.6 wt% S or 10.5 wt% Si for Mercury, 9.8 wt% S or 18.3 wt% Si for the Moon, and 32.4 wt% S or 30.3 wt% Si for Mars. In these core compositions, differences in sound velocity profiles between an Fe‐Ni‐S and Fe‐Ni‐Si core in Mercury are small, whereas for Mars and the Moon, the differences are substantially larger and could be detected by upcoming seismic sounding missions to those bodies.

Structural and acoustic properties of transparent chitosan aerogel

The first report on acoustic absorption properties of transparent biopolymer aerogel is provided. Cross-linked chitosan aerogel prepared by supercritical carbon dioxide drying has a homogeneous nanofibrous structure with mesopores, the major size of which decreases from ∼45 to ∼20 nm with increasing apparent density. The aerogel shows peak-shaped sound absorption profiles, regardless of the density. This absorption is attributable to sample vibration reflecting an extremely high flow resistivity of the mesoporous structure.

Investigation on the design of a novel selective laser melted insert for extrusion dies with conformal cooling channels

The thermal control and the maintenance of a uniform temperature in the extrusion process of aluminum alloys is a crucial task in order to generate sound profiles with high press productivities. This can be accomplished through liquid nitrogen flowing in Conformal Cooling Channels (CCC). The Selective Laser Melting (SLM) additive technology offers an optimal solution for an unlimited flexibility of the cooling system, thus allowing tailored cooling strategies. In the present work, a smart thermally controlled die made by AISI H13 was designed aimed at maximizing and regulating the cooling efficiency by means of CCC. In the novel die concept, the expensive SLM insert with CC channels, has been integrated into a conventionally machined steel housing. A comprehensive numerical investigation has been performed in order to check the insert designs mechanical and thermal performances both in uncooled and cooled conditions. Then, eight inserts were additively manufactured by means of the SLM process with the aim to preliminary verify their experimental feasibility and overall quality. As main results, it was numerically proved the capability of the novel insert design to allow a significantly increase of the production rate and it was experimentally demonstrated the insert manufacturability throughout the SLM technology.

Banda sonora e identidades en la generación “Y”

Desde los comienzos del cine, en los que una sola persona se ocupaba prácticamente de todo, la organización de la creación de un film fue evolucionando, y las diversas funciones del proceso fueron aumentando y especializándose progresivamente. La noción de autoría colectiva es un concepto difícil de abordar y de comprender en toda su dimensión. En este artículo se pretende analizarlo, tras estudiar de qué modo la estructura de colaboración en equipo de aquella época influía en sus creadores, y por qué razón se considera que unos son autores, mientras a otros se les niega esa condición. Para examinar a fondo cuál era el sistema de trabajo real de los distintos oficios se La televisión ha tenido una importancia innegable en los años 90 en España, sobre todo para los niños y jóvenes que pertenecen a la llamada generación “Y” o “Millennials”. Este grupo ha crecido paralelamente a la tecnología doméstica y las redes sociales, haciendo de los entornos audiovisuales su hábitat natural. En este contexto, las series televisivas de animación de dicha época causaron una gran influencia en este colectivo que estaba entonces en pleno crecimiento y formación. Nuestro estudio pretende analizar las características sonoras de las cabeceras de las 20 series de animación infantil más vistas en las televisiones españolas de ámbito estatal en los años 90, mediante la aplicación de una plantilla de análisis sonoro-musical validada y aplicada en investigaciones anteriores por diversos autores. Con todo ello se caracteriza el paisaje sonoro que acompañó a esta generación en su infancia, distinguiendo entre distintos perfiles sonoros. Para ello, se analiza la presencia o ausencia de determinados elementos sonoros y musicales, originales o manipulados mediante técnicas de postproducción, orientados a distintos públicos según el sexo, la edad, las emociones, la motivación por la tecnología o por las relaciones sociales. Así pues, se plantea profundizar y sustentar la heterogeneidad presente en los individuos de esta generación, huyendo de clichés homogeneizadores, posibilitando modos distintos de acercamiento a su identidad social y a la riqueza que estos representan para la sociedad española actual, partiendo del sonido que les acompañó y marcó en su infancia.

GIGJ: A Crustal Gravity Model of the Guangdong Province for Predicting the Geoneutrino Signal at the JUNO Experiment

AbstractGravimetric methods are expected to play a decisive role in geophysical modeling of the regional crustal structure applied to geoneutrino studies. GIGJ (GOCE Inversion for Geoneutrinos at JUNO) is a 3‐D numerical model constituted by ~46 × 103 voxels of 50 × 50 × 0.1 km, built by inverting GOCE (Gravity field and steady‐state Ocean Circulation Explorer) gravimetric data over the 6° × 4° area centered at the JUNO (Jiangmen Underground Neutrino Observatory) experiment, currently under construction in the Guangdong Province (China). The a priori modeling is based on the adoption of deep seismic sounding profiles, receiver functions, teleseismic P wave velocity models, and Moho depth maps, according to their own accuracy and spatial resolution. The inversion method allowed for integrating GOCE data with the a priori information and some regularization conditions through a Bayesian approach and a stochastic optimization. GIGJ fits the highly accurate and homogeneously distributed GOCE gravity data with a ~1 mGal standard deviation of the residuals, compatible with the observation accuracy. GIGJ provides a site‐specific subdivision of the crustal layers masses, of which uncertainties include estimation errors, associated to the gravimetric solution, and systematic uncertainties, related to the adoption of a fixed sedimentary layer. A consequence of this local rearrangement of the crustal layer thicknesses is a ~21% reduction and a ~24% increase of the middle and lower crust geoneutrino signal, respectively. The geophysical uncertainties of geoneutrino signals at JUNO produced by unitary uranium and thorium abundances distributed in the upper, middle, and lower crust are reduced by 77%, 55%, and 78%, respectively. The numerical model is available at this site (http://www.fe.infn.it/radioactivity/GIGJ).

Analysis of the Influence about Uncertain Sound Velocity on the Positioning of Seafloor Control Points

The method of determining the coordinates of seafloor control network is introduced. The change law of the sound velocity profile and the influence of this change on ranging error are analyzed, finally, summarizes the problems existing in the determination of the seafloor control network.

Study on the integrated calculation method of fluid–structure interaction vibration, acoustic radiation, and propagation from an elastic spherical shell in ocean acoustic environments

A modeling method based on the wave superposition method is studied in this paper. Different underwater acoustic propagation models are used in the near and far field. Taking the acoustic radiation field calculation of an elastic spherical shell as an example, the near and far field can be analyzed as a unified system, using this method. Many studies use FEM/BEM (finite element method/boundary element method) to calculate acoustic radiation fields of elastic structures, but only a few of these methods can be applied when considering finite ocean depth, seafloor reflection loss, and sound velocity profile. In this study, the Green function is calculated differently in the near and far field to significantly simplify calculations. The virtual source method is used to calculate the acoustic radiation field in the near field and source strength, while the normal mode method is used in the far field. The results are compared with those obtained using the COMSOL finite element software, which showed that this method was both computationally efficient and accurate. Based on numerical examples, the influence of sea surface, seafloor, and sound velocity on the acoustic radiation field of elastic structures in an ocean acoustic environment is quantitatively analyzed.

Sound velocity profile estimation using ray tracing and nature inspired meta‐heuristic algorithms in underwater sensor networks

In water, the velocity of sound is a function of temperature, pressure, and salinity. The sound velocity in the ocean varies with depth and estimation of the sound velocity profile is interesting in its right for environmental monitoring. The sound velocity profile is required for sound navigation and ranging signal processing algorithms such as MUSIC. Also, the localisation of sensor nodes in an underwater sensor network requires a good estimate of the velocity profile. This study proposes an algorithm that calculates the sound velocity profile of ocean water using time of flight measurements between anchor nodes. The velocity profile is estimated in the discrete cosine transform domain to reduce the complexity of the algorithm, using two well-known meta-heuristic algorithms namely artificial bee colony and firefly algorithms. The Ray tracing method is used to improve the accuracy of the velocity profile. The Cramer–Rao lower bound of the proposed scheme is also derived. The localisation of a target node is also performed using the estimated sound velocity profile.

Bayesian calibration of underwater propagation models under uncertainty

Propagation models are notorious for the uncertainty of important parameters such as source strength, speed of sound profiles, and reflecting surface profiles. In many cases, one calibrates a model to measured data (e.g., sound levels or transmission loss) for the purposes of estimating these model parameters, i.e., for inverse modeling. Bayesian calibration methods have been developed that are extremely useful for calibration of models where parameters have high levels of uncertainty and problems may be under or over determined. The Kennedy and O’Hagen framework which uses a Gaussian process surrogate model to replace the model under calibration is especially useful when the underlying model is computationally expensive, and so, it may be difficult to apply many optimization based calibration methods. In this talk, we describe the application of the Kennedy and O’Hagen Bayesian Calibration framework to the calibration of an underwater ray tracing propagation model. The source strength and parameters for the sound speed profile are considered as highly uncertain. The Bayesian calibration technique is shown to improve model prediction and reduce the uncertainty of the unknown propagation parameters.

The Relationship between Propagation Time and Sound Velocity Profile for Positioning Seafloor Reference Points

This paper focuses on the relationship between the propagation time and the integral of the sound velocity profile (SVP) with respect to depth (SVP area for short) for positioning seafloor reference points. We proved a linear relationship between the propagation time and the SVP area and defined its mathematical expression (ST law). We showed in three simulations of possible variations in SVPs (random errors, internal waves, or a combination of both) that this ST law is verified. Using this new law in a simulated experiment, the ranging residuals due to sound velocity change through time are significantly improved. With this method, monitoring the SVP while acquiring travel times to a submerged transponder can significantly reduce the positioning errors of the transponder.