Search results for: ACOUSTIC
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On statistical linear inverse problems in fishery acoustic
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Acoustic heating in a weakly dispersive fluid flow
PublicationZbadano specyficzną rolę dyspersyjnych własności płynu w generacji ogrzewania przez straty energii fali akustycznej. Przedstawiono ilustracje zaistniałego ogrzewania powstającego na skutek przejścia dwoch typów fal - impulsowej i stacjonarnej.
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Examining Acoustic Emission of Engineered Ultrasound Loudspeakers
PublicationMeasurement results of the sound emitted from an ultrasound custom-made system with high spatial directivity are presented. The proposed system is using modulated ultrasound waves which demodulate in nonlinear medium resulting in audible sound. The system is aimed at enhancing the users’ personal audio space, therefore the measurements are performed using the Head and Torso Simulator which provides the realistic reproduction of...
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Vowel recognition based on acoustic and visual features
PublicationW artykule zaprezentowano metodę, która może ułatwić naukę mowy dla osób z wadami słuchu. Opracowany system rozpoznawania samogłosek wykorzystuje łączną analizę parametrów akustycznych i wizualnych sygnału mowy. Parametry akustyczne bazują na współczynnikach mel-cepstralnych. Do wyznaczenia parametrów wizualnych z kształtu i ruchu ust zastosowano Active Shape Models. Jako klasyfikator użyto sztuczną sieć neuronową. Działanie systemu...
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Fish size distribution from acoustic data
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Pressure Dependence of Acoustic Modes in AgGaSe 2
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Acoustic verification on onomatopoeic sets in contrastive approach
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Acoustic verification on onomatopoeic sets in contrastive approach
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Photo-acoustic response of active biological systems
PublicationZbadano dwie próbki organiczne gatunku Trunculariopsis trunculus,jedną wilgotną, drugą - suchą. W obu przypadkach zaobserwowanointensywne szerokie pasma absorpcyjne w zakresie widzialnym (żółtymi poniżej 330 nm). Widma foto-akustyczne zawierają wszystkie pasma uznane za związane z aktywnością biologiczną.
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Development of the urban rail vehicle acoustic model
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An application of acoustic sensors for the monitoring of road traffic
PublicationAssessment of road traffic parameters for the developed intelligent speed limit setting decision system constitutes the subject addressed in the paper. Current traffic conditions providing vital data source for the calculation of the locally fitted speed limits are assessed employing an economical embedded platform placed at the roadside. The use of the developed platform employing a low-powered processing unit with a set of microphones,...
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Microscopic parameters of gas via acoustic measurements
PublicationProponujemy wstępną analizę odwrotnego problemu, który sformułowano, opartą na statycznej mechanice /termodynamice, rozważającej gaz jako środek rozprzestrzeniania dzwięku.
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Detection of the acoustic interferences during AFM operation
Open Research DataAtomic force microscopy is a particularly complicated surface imaging technique due to the large number of factors that affect the quality of the resulting images. They are obviously difficult and sometimes even impossible to control at the same time. One of such factors may even be the seismological location of the building or the influence of mechanical...
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Acoustic heating produced in resonators filled by a newtonian fluid
PublicationAcoustic heating in resonators is studied. The governing equation of acoustic heating is derived by means of the special linear combination of conservation equations in differential form, allowing the reduction of all acoustic terms in the linear part of the final equation, but preserving terms belonging to the thermal mode responsible for heating. This equation is instantaneous and includes nonlinear acoustic terms that form a...
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The Examination of the Upper Layers of the Seabed by the Means of the Acoustic Methods
PublicationPropagation of acoustic waves in the sea, in particular in shallow sea, depends on several factors. The basic of them are source power and frequency of acoustic waves, spatial distribution inhomogeneous medium in which acoustic wave propagates, and distributions of speed of sound and density of seawater. The coastal conditions, which limit water medium from above (free surface of the sea) and from bottom (the seabed), are no less...
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Theoretical Model of Acoustic Wave Propagation in Shallow Water
PublicationThe work is devoted to the propagation of low frequency waves in a shallow sea. As a source of acoustic waves, underwater disturbances generated by ships were adopted. A specific feature of the propagation of acoustic waves in shallow water is the proximity of boundaries of the limiting media characterised by different impedance properties, which affects the acoustic field coming from a source situated in the water layer “ deformed”...
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Acoustic heating produced in the thermoviscous flow of a Bingham plastic
PublicationThis study is devoted to the instantaneous acoustic heating of a Bingham plastic. The model of the Bingham plastic's viscous stress tensor includes the yield stress along with the shear viscosity, which differentiates a Bingham plastic from a viscous Newtonian fluid. A special linear combination of the conservation equations in differential form makes it possible to reduce all acoustic terms in the linear part of of the final equation...
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Acoustic heating produced in the thermoviscous flow of a bingham plastic
PublicationThis study is devoted to the instantaneous acoustic heating of a Bingham plastic. The model of the Bingham plastic's viscous stress tensor includes the yield stress along with the shear viscosity, which differentiates a Bingham plastic from a viscous Newtonian fluid. A special linear combination of the conservation equations in differential form makes it possible to reduce all acoustic terms in the linear part of of the final equation...
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Acoustic Hysteresis in Flows with Different Kinds of Relaxation and Attenuation
PublicationGraphs in the thermodynamic plane acoustic pressure versus excess acoustic density representing acoustic hysteresis, are considered as indicators of relaxation processes, equilibrium parameters of a flow, and kinds of wave exciters. Some flows with deviation from adiabaticity are examined: the Newtonian flow of a thermocon- ducting gas, the flow of a gas with vibrational relaxation, the flow of liquid electrolyte with a chemical...
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A system for acoustic field measurement employing cartesian robot
PublicationA system setup for measurements of acoustic field, together with the results of 3D visualisations of acoustic energy flow are presented in the paper. Spatial sampling of the field is performed by a Cartesian robot. Automatization of the measurement process is achieved with the use of a specialized control system. The method is based on measuring the sound pressure (scalar) and particle velocity (vector) quantities. The aim of the...