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Search results for: SOUND ABSORPTION COEFFICIENT
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Low-Cost Surrogate Models for Microwave Filters
PublicationA novel low-cost kriging-based multivariable parametric macromodeling technique for microwave filters is presented. Kriging is used to model both the residues and poles of a microwave filter's reflection coefficient, and the zeros of the transmission coefficient. The proposed residue-pole-zero (RPZ) technique is demonstrated to efficiently model a high dimensional (8D) microwave filter with pseudoelliptic characteristics.
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Nonlinear properties of the Gotland Deep – Baltic Sea
PublicationThe properties of the nonlinear phenomenon in water, including sea water, have been well known for many decades. The feature of the non homogeneous distribution of the speed of sound along the depth of the sea is very interesting from the physical and technical point of view. It is important especially in the observation of underwater area by means of acoustical method ( Grelowska et al ., 2013; 2014). The observation of the underwater...
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Temperature influence on tyre/road noise frequency spectra
PublicationThe correction for temperature effect on measured tyre/road noise is very important as it may be one of the main sources of errors in measurement results due to substantial influence of this parameter on obtained values. The latest version of the Technical Specification ISO/CD TS 13471-1 about Temperature Corrections contains a proposal of correction procedure for normalizing measured noise levels to a reference air temperature...
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Modelling of saturated, subcooled and post-dryout flow boiling with the energy dissipation based semi-empirical model
PublicationA comprehensive semi-empirical model for saturated, subcooled and post dryout heat transfer is presented based on considerations of energy dissipation in the flow. The fundamental hypothesis in the model is the fact that heat transfer during flow boiling can be treated as a sum of two contributions constituting the total energy dissipation in the flow, namely the energy dissipation due to the shearing flow without the bubbles and...
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Direct determination of paraquat herbicide by square-wave voltammetry by two-step transfer mechanism at heterogeneous boron-doped carbon nanowall electrodes
PublicationBoron-doped carbon nanowalls (B:CNW) versus boron-doped diamond (BDD) materials were investigated for the effective electrochemical detection of highly toxic herbicide paraquat (PQ). Depending on the surface morphology and functional groups of BDD and B:CNWs, the electrochemical absorption and detection of the target analyte PQ revealed different detection mechanisms. The surface absorption mechanism was mainly observed for BDD,...
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Comment on "Quantitative comparison of analysis methods for spectroscopic optical coherence tomography"
PublicationIn a recent paper by Bosschaart et al. [Biomed. Opt. Express 4, 2570 (2013)] various algorithms of time-frequency signal analysis have been tested for their performance in blood analysis with spectroscopic optical coherence tomography sOCT). The measurement of hemoglobin concentration and oxygen saturation based on blood absorption spectra have been considered. Short time Fourier transform (STFT) was found as the best method for...
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Engineering Au nanoparticle arrays on SiO2 glass by pulsed UV laser irradiation
PublicationWe study semi-regular arrays of Au nanoparticles (NP) obtained via UV laser irradiation of thin Au films on glass substrate. The NP structures are prepared from films of a thickness up to 60 nm produced by discharge sputtering or pulsed laser deposition, and annealed by nanosecond laser pulses at 266 or 308 nm, respectively, at fluencies in the range of 60-410 mJ/cm2. For the rare- and close-packed NP structures, consistent description...
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HYDROACOUSTIC NOISE MEASUREMENTS
PublicationThe paper deals mainly with investigation of underwater noise that propagation is in shallow water. In this paper has been presented the experimental investigation results concerning the distribution of the sound field pressure generated by moving ships in the shallow water at the small distance from the ship. The main acoustical characteristics describing features of the field are spectrograms in pseudo 3D system – distance and frequency...
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Gini index in selected European Union countries in 2017.
Open Research DataWhen assessing the level of poverty, one should use indicators presenting indicators of social inequality in terms of income, indicators of prosperity and poverty. In Poland, the situation in terms of inequality is improving, but as measured by the Gini coefficient.
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Synthesis and Spectroscopic Properties of New Bis-tetrazoles
PublicationSyntheses of N,N'-phenyltetrazole podands link with aliphatic chains containing oxygen, nitrogen and sulphur atoms, are described. The complexing properties of these compounds towards metal cations (Fe2+, Cu2+, Zn2+, Co2+, Ni2+) were investigated by absorption and infrared spectroscopy. The UV-Vis titrations were performed to estimate the stability constant values of the respective complexes with Cu2+ ion. Changes in UV-Vis absorption...
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rigid polyurethane foams modified with selected nanofillers
PublicationThe nanofillers: natural montmoryllonite (MMT) - Bentonite, natural MMT modified with a quaternary ammonium salt - Cloisite30B, has been used in rigid polyurethane foams (PUFs). The influence of fillers amounts on processing parameters, physical-mechanical properties (density, water absorption, brittleness and compression strength) and thermal properties (thermal stability, fire behaviours) of such foams has been analysed. The...
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Chladni and circular saw disc vibrations visualisation
PublicationIn this paper are described some methods for saw disc vibration monitoring in march of time (chronology). Ernst Chaldni, the father of sound visualisation and his patternsis are mentioned. In the last partof article are introduced results received with authors measuring systems.
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Ocena klimatu akustycznego w przestrzeni pasażerskiej elektrycznego zespołu trakcyjnego serii EN57
PublicationW pracy przedstawiono wyniki badań poziomów dźwięku w przestrzeni pasażerskiej elektrycznego zespołu trakcyjnego (EZT) serii EN57 podczas postoju, rozruchu, jazdy oraz hamowania. Badania przeprowadzono na podstawie autorskiej metodyki badawczej bazując na normie PNEN ISO 3381:Kolejnictwo. Akustyka. Pomiar hałasu wewnątrz pojazdów szynowych. Badania przeprowadzono na linii kolejowej nr 250 od przystanku Gdańsk Śródmieście do stacji...
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An automated, low-latency environment for studying the neural basis of behavior in freely moving rats
PublicationBackground Behavior consists of the interaction between an organism and its environment, and is controlled by the brain. Brain activity varies at sub-second time scales, but behavioral measures are usually coarse (often consisting of only binary trial outcomes). Results To overcome this mismatch, we developed the Rat Interactive Foraging Facility (RIFF): a programmable interactive arena for freely moving rats with multiple feeding...
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Retrospecting Polish Audio Engineering Society Membership on 20th Anniversary of the Polish Section of the Audio Engineering Society
PublicationIn this article some key events concerning founding Polish Section of the Audio Engineering Society were presented. In addition, the history covering International Symposia on Sound Engineering and Mastering was outlined. Also, papers contained in this issue were shortly reviewed.
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Editor's note and 2018 reviewers
PublicationPrzedmiotem pracy jest odniesienie do prac opublikowanych w 2018 roku, jak również do serii artykułów w ramach specjalnego wydania: Special Issue on Augmented and Participatory Sound and Music Interaction Using Semantic Audio.
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Audio-visual surveillance system for application in bank operating room
PublicationAn audio-visual surveillance system able to detect, classify and to localize acoustic events in a bank operating room is presented. Algorithms for detection and classification of abnormal acoustic events, such as screams or gunshots are introduced. Two types of detectors are employed to detect impulsive sounds and vocal activity. A Support Vector Machine (SVM) classifier is used to discern between the different classes of acoustic...
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Processing of acoustical data in a multimodal bank operating room surveillance system
PublicationAn automatic surveillance system capable of detecting, classifying and localizing acoustic events in a bank operating room is presented. Algorithms for detection and classification of abnormal acoustic events, such as screams or gunshots are introduced. Two types of detectors are employed to detect impulsive sounds and vocal activity. A Support Vector Machine (SVM) classifier is used to discern between the different classes of...
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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...
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Changes in conditions of acoustic wave propagation in the Gdansk deep as an effect of climate changes in the Baltic Sea region
PublicationThe article presents the results from a research project investigating acoustic climate changes in the Gdansk Deep based on data extending from 1902 to 2019. This part of the southern Gotland Basin, is rarely discussed in the scientific literature. The speed of sound in the seawater is a function of temperature, salinity, and depth. In such shallow sea as Baltic Sea, the impact of depth is not substantial. The other two factors...
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Pursuing Listeners’ Perceptual Response in Audio-Visual Interactions - Headphones vs Loudspeakers: A Case Study
PublicationThis study investigates listeners’ perceptual responses in audio-visual interactions concerning binaural spatial audio. Audio stimuli are coupled with or without visual cues to the listeners. The subjective test participants are tasked to indicate the direction of the incoming sound while listening to the audio stimulus via loudspeakers or headphones with the head-related transfer function (HRTF) plugin. First, the methodology...
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Wpływ kąta pochylenia koła na opór toczenia opon samochodowych
PublicationW pracy przedstawiono wpływ kąta pochylenia koła na opór toczenia opon do samochodów osobowych. Pomiary oporu toczenia kół toczących się z kątem pochylenia od -6º do +3º wykonano na bębnowej maszynie bieżnej metodą momentową. Wyniki pomiarów przedstawiono w formie zależności współczynnika oporu toczenia oraz przyrostu współczynnika oporu toczenia w funkcji kąta pochylenia badanego koła.
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Natural ventilation performance of family building in cold climate during windless time
PublicationIn this paper, the field measurements results are presented on the stack ventilation effect. The paper presents the results of performance (air change rate ACH) natural ventilation for building with inlet gap measured for the transitional season (between heating and summer season). The measurements were performed during a windless time. The house was located in northern Poland, in a cold climate region. The measurement system...
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Analytical chemistry in technical approaches: immobilization of biosorbent waste containing heavy metals in cemented materials
PublicationAn ecologically safe and economically justified method of stabilization of the used biosorbents was developed. Sorbent contaminated with heavy metals has been successfully solidified/stabilized using a hydraulic binder. The test results indicated that up to 1% of the biosorbent residue used could be added without compromising the compressive strength of the mortar. The compressive strength of the modified mortars did not change...
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Effect of pavement roughness and vehicle dynamic loads on decrease of fatigue life of flexible pavements
PublicationDue to the fact that pavement surfaces are not ideally even, dynamic loads of vehicle axles deviate from static loads. Higher dynamic loads contribute to faster pavement distress. The distribution of dynamic loads is similar to normal distribution and can be described by static load and factors DI (dynamic impact) and DLC (dynamic load coefficient). With the deterioration of pavement condition its evenness decreases as well and...
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Investigation of plasmon resonance in a silver nanoparticles
Open Research DataSilver nanostructures were prepared on borosilicate glass (Corning 1737F) substrates. Thin Ag films (1–9 nm thickness) were deposited using a table-top dc magnetron sputtering coater (EM SCD 500, Leica) in pure Ar plasma (argon, Air Products 99.999%). The Ag target was of 99.99% purity, the rate of layer deposition was about 0.4 nm·s−1, and the incident...
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A Novel Ru(II) Polypyridine Black Dye Investigated by Resonance Raman Spectroscopy and TDDFT Calculations
PublicationThe optical properties of a new(bipyridine)2Ru(4H-imidazole) complex presenting a remarkablebroad absorption in the visible range are investigated. Thestrong overlap of the absorption with the solar radiationspectrum renders the studied complex promising as a blackabsorber and hence as a starting structure for applications inthe field of dye-sensitized solar cells. The correlations betweenstructural and electronic features for...
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Comparative study of flow condensation in conventional and small diameter tubes
PublicationFlow boiling and flow condensation are often regarded as two opposite or symmetrical phenomena, however their description with a single correlation has yet to be suggested. In the case of flow boiling in minichannels there is mostly encountered the annular flow structure, where the bubble generation is not present. Similar picture holds for the case of inside tube condensation, where annular flow structure predominates. In such...
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The unstable thermoelectric effect in non-stoichiometric Cu2Se during the non-equilibrium phase transition
PublicationThe superionic α ↔ β phase transition in Cu1.96Se thermoelectric material is investigated by means of thermal analysis (DSC) and measurements of Seebeck coefficient and electrical conductivity. Results of the DSC measurements with 1–10 K/min heating and cooling rates show that the material is close to the equilibrium phase composition during the transformation. However, the kinetic limitation of the process exists, which is indicated...
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Changes in conditions of acoustic wave propagation in the Gdansk deep as an effect of climate changes in the Baltic Sea region
PublicationThe article presents the results from a research project investigating acoustic climate changes in the Gdansk Deepbased on data extending from 1902 to 2019. This part of the southern Gotland Basin, is rarely discussed in thescientific literature.The speed of sound in the seawater is a function of temperature, salinity, and depth. In such shallow sea asBaltic Sea, the impact of depth is not substantial....
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Detection, classification and localization of acoustic events in the presence of background noise for acoustic surveillance of hazardous situations
PublicationEvaluation of sound event detection, classification and localization of hazardous acoustic events in the presence of background noise of different types and changing intensities is presented. The methods for discerning between the events being in focus and the acoustic background are introduced. The classifier, based on a Support Vector Machine algorithm, is described. The set of features and samples used for the training of the...
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Study of preference for surround microphone techniques, used in the recording of choir and instrumental ensemble
PublicationThe aim of this paper is to describe the process of choosing the best surround microphone technique for recording of choir with an instrumental ensemble. First, examples of multichannel microphone techniques including those used in the recording are described. Then, the assumptions and details of music recording in Radio Gdansk Studio are provided as well as the process of mixing of the multichannel recording. The extensive subjective...
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Counting and tracking vehicles using acoustic vector sensors
PublicationA method is presented for counting vehicles and for determining their movement direction by means of acoustic vector sensor application. The assumptions of the method employing spatial distribution of sound intensity determined with the help of an integrated 3D intensity probe are discussed. The intensity probe developed by the authors was used for the experiments. The mode of operation of the algorithm is presented in conjunction...
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A Method for Optimising the Blade Profile in Kaplan Turbine
PublicationThis paper introduces a method of blade profile optimisation for Kaplan-type turbines, based on modelling the interaction between rotor and stator blades. Rotor and stator blade geometry is described mathematically by means of a midline curve and thickness distribution. Genetic algorithms are then used to find a global optimum that minimises the loss coefficient. This allows for variety of possible blade shapes and configurations....
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Enhanced electrochemical performance of partially amorphous La0.6Sr0.4CoO3-δ oxygen electrode materials for low-temperature solid oxide cells operating at 400 °C
PublicationThis work evaluates partially amorphous La0.6Sr0.4CoO3-δ (LSC) as a potential oxygen electrode for lowtemperature solid oxide cells. LSC was deposited using the spin-coating technique onto Ce0.8Gd0.2O2-δ (CGO) substrates. The optimal oxygen electrode thickness was determined as 500 nm. The electrochemical impedance spectroscopy (EIS) study showed a significant improvement in oxygen reduction/oxidation reaction kinetics when annealing...
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Electronic States of Tris(bipyridine) Ruthenium(II) Complexes in Neat Solid Films Investigated by Electroabsorption Spectroscopy
PublicationWe present the electric field-induced absorption (electroabsorption, EA) spectra of the solid neat films of tris(bipyridine) Ru(II) complexes, which were recently functionalized in our group as photosensitizers in dye-sensitized solar cells, and we compare them with the results obtained for an archetypal [Ru(bpy)3]2+ ion (RBY). We argue that it is difficult to establish a unique set of molecular parameter values by discrete parametrization...
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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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A simplified energy dissipation based model of heat transfer for post-dryout flow boiling
Publicationmodel for post dryout mist flow heat transfer is presented based on considerations of energy dissipation in the flow. The model is an extension of authors own model developed earlier for saturated and subcooled flow boiling. In the former version of the model the heat transfer coefficient for the liquid singlephase convection as a reference was used, due to the lack of the appropriate model for heat transfer coefficient for the...
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Does migration lead to economic convergence in an enlarged European market?
PublicationThis paper examines the relationship between migration and convergence for the enlarged internal market of the European Union (EU27) for the period 1990-2007. The impact of migration on growth is estimated in two ways: by including the migration rate in a growth regression and examining its impact on the convergence coefficient; and from the actual coefficient on migration, which can be interpreted as the effect of migration on...
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Mesh dependence study for numerical assessment of hydrodynamic characteristics of windsurfing fin
PublicationThe presented research aims to assess the drag coefficient and lift coefficient versus angle of attack curves for windsurfing fin. Special attention in the research was being paid to the evaluation of the stall angle value. The angle of incidence for which the stall occurs was searched, and the sensitivity of the solution for the mesh resolution was studied. The mesh resolution sensitivity analysis was done by systematically decreasing...
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MODELLING OF THE VISCOSITY EFFECT OF HEAVE PLATES FOR FLOATING WIND TURBINES BY HYDRODYNAMIC COEFFICIENTS
PublicationOne of the methods of modelling the movement of floating wind turbines is the use of the diffraction method. However, this method does not take into account the influence of viscosity; therefore, in many cases, it needs to be extended with a matrix of appropriate coefficients. The effect of viscosity causes both the added mass coefficient and the damping coefficient to increase. The determined coefficients were entered into the...
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Use of optical skin phantoms for preclinical evaluation of laser efficiency for skin lesion therapy
PublicationSkin lesions are commonly treated using laser heating. However, the introduction of new devices into clinical practice requires evaluation of their performance. This study presents the application of optical phantoms for assessment of a newly developed 975-nm pulsed diode laser system for dermatological purposes. Such phantoms closely mimic the absorption and scattering of real human skin (although not precisely in relation to...
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Antimony substituted lanthanum orthoniobate proton conductor – structure and electronic properties.
PublicationX‐ray and neutron diffraction have been utilized to analyze the crystalline and electronic structure of lanthanum orthoniobate substituted by antimony. Using X‐ray absorption spectroscopy and photoelectron spectroscopy, changes in the electronic structure of the material upon substitution have been analyzed. The structural transition temperature between fergusonite and scheelite phases for 30 mol% antimony substitution was found...
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Simulation of perovskite-based CuI/CH3NH3PbI3/TiO2 solar cell performance
Open Research DataThe presented data set is part of the theoretical research on novel thin-layer lead-halide perovskite solar cells with different inorganic transparent conductive oxides used as charge transport layers. In this study CuI/CH3NH3PbI3/TiO2 model structure (Model 1) was investigated by the use of the SCAPS-1D simulation method (https://scaps.elis.ugent.be/).
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Simulation of perovskite-based CuI/CH3NH3PbI3/SnO2 solar cell performance
Open Research DataThe presented data set is part of the theoretical research on novel thin-layer lead-halide perovskite solar cells with different inorganic transparent conductive oxides used as charge transport layers. In this study CuI/CH3NH3PbI3/SnO2 model structure (Model 2) was investigated by the use of the SCAPS-1D simulation method (https://scaps.elis.ugent.be/).
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Simulation of perovskite-based CuI/CH3NH3PbI3/ZnO solar cell performance
Open Research DataThe presented data set is part of the theoretical research on novel thin-layer lead-halide perovskite solar cells with different inorganic transparent conductive oxides used as charge transport layers. In this study CuI/CH3NH3PbI3/ZnO model structure (Model 3) was investigated by the use of the SCAPS-1D simulation method (https://scaps.elis.ugent.be/).
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Tellurite based glass doped by Eu3+ ions - XPS measurements
Open Research DataEu3+ doped tellurite glass ceramics containing SrF2 nanocrystals were prepared using melt quenching technique and subsequent heat treatment of glass in 370 °C for different time periods. Thermal properties of glass matrix have been determined based on DSC measurements. XRD and XPS results confirmed formation of SrF2 nanocrystals in glass matrices after...
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Waveguide model of the hearing aid earmold system
PublicationBackground The earmold system of the Behind-The-Ear hearing aid is an acoustic system that modifies the spectrum of the propagated sound waves. Improper selection of the earmold system may result in deterioration of sound quality and speech intelligibility. Computer modeling methods may be useful in the process of hearing aid fitting, allowing physician to examine various earmold system configurations and choose the optimum one...
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Waveguide model of the hearing aid earmold system
PublicationBackground The earmold system of the Behind-The-Ear hearing aid is an acoustic system that modifies the spectrum of the propagated sound waves. Improper selection of the earmold system may result in deterioration of sound quality and speech intelligibility. Computer modeling methods may be useful in the process of hearing aid fitting, allowing physician to examine various earmold system configurations and choose the optimum one...
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Interaction between acoustic and non-acoustic mode in bubbly liquid
PublicationThe nonlinear interaction of acoustic and entropy modes in a bubbly liquid is the subject of investigation. Thedynamic equation governing an excess density of the entropy mode is derived. Nonlinearity and dispersion are the reasons forexcitation of the entropy mode. The nonlinear interaction of modes as a reason for bubble to grow due to sound, is discovered.Some numerical examples of the modes interactions are made.