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Wyszukujesz frazę "acoustic properties" wg kryterium: Wszystkie pola

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    Wyświetlanie 1-8 z 8
    Tytuł:
    Investigation of the Acoustic Properties of Viscosity Standards
    Autorzy:
    Kazys, R.
    Voleisis, A.
    Sliteris, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/176493.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    viscosity standard
    longitudinal and shear waves
    ultrasound velocity
    Opis:
    Longitudinal and shear ultrasonic wave velocities were measured versus temperature in the viscosity standards of Paragon S8000S, N30000S and Cannon N2700000. The measurements were performed by the through-transmission method at the frequency of 2 MHz. Ultrasonic pulses were sent via polymethyl methacrylate (PMMA) waveguides between the tips of which a small amount of the particular standard liquid was placed. The velocities of longitudinal and shear waves were determined to depend on the viscosity of the liquid and increase with the viscosity.
    Źródło:
    Archives of Acoustics; 2016, 41, 1; 55-58
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Effect of Sonication on Acoustic Properties of Biogenic Ferroparticle Suspension
    Autorzy:
    Józefczak, A.
    Hornowski, T.
    Król, A.
    Molčan, M.
    Leszczyński, B.
    Timko, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/176978.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    magnetosomes
    sonication
    ultrasonic properties
    Opis:
    Superparamagnetic iron oxide nanoparticles (SPION) synthesised chemically usually need the modification of the particle surface. Other natural sources of magnetic particles are various magnetotactic bacteria. Magnetosomes isolated from magnetotactic bacteria are organelles consisting of magnetite (Fe3O4) or greigite (Fe3S4) crystals enclosed by a biological membrane. Magnetotactic bacteria produce their magnetic particles in chains. The process of isolation of magnetosome chains from the body of bacteria consists of a series of cycles of centrifugation and magnetic decantation. Using a high-energy ultrasound it is possible to break the magnetosome chains into individual nanoparticles – magnetosomes. This study presents the effect of sonication of magnetosome suspension on their acoustic properties, that is speed and attenuation of the sound. Acoustic propagation parameters are measured using ultrasonic spectroscopy based on FFT spectral analysis of the received pulses. The speed and attenuation of ultrasonic waves in magnetosome suspensions are analysed as a function of frequency, temperature, magnetic field intensity, and the angle between the direction of the wave and the direction of the field.
    Źródło:
    Archives of Acoustics; 2016, 41, 1; 161-168
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of High-tin Bronze Composition on Physical, Mechanical, and Acoustic Properties of Gamelan Materials
    Autorzy:
    Slamet, S.
    Suyitno, S.
    Kusumaningtyas, I.
    Miasa, I. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1837824.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    tin bronzes
    mechanical properties
    acoustic properties
    gamelan
    sand casting
    brązy cynowe
    właściwości mechaniczne
    właściwości akustyczne
    odlewanie piaskowe
    Opis:
    High tin bronze alloy (Cu>17wt.%Sn) is commonly as raw material to fabricate musical instruments. Gamelan musical instruments in Indonesia are produced using tin bronze alloy raw materials. The tin bronze alloy used by each gamelan craftsman has a different tin composition, generally in the range of Cu(20-24) wt.% Sn. This study aims to investigate the effect of microstructure, density, and mechanical properties of Cu(20-24)wt.%Sn against the acoustic properties processed by the sand casting method. The material is melted in a crucible furnace until it reaches a pouring temperature of 1100ºC by the sand casting method. The specimens were subjected to microstructure observations, density and porosity as well as mechanical properties testing including tensile strength, bending strength, hardness, and modulus of elasticity. Mechanical properties data then used to calculate several parameters of acoustic properties including speed of sound (c), impedance (z) and radiation coefficient (R). Processes simulation using Finite Element Analysis (FEA) and Experiment Method Analysis (EMA) were carried out to determine acoustic properties including sound intensity, natural frequency and damping capacity. The experimental result shows that the increase in tin composition in Cu(20-24) wt.% Sn changed the microstructure of coarse grains into dendrite-columned fine grains. Physical properties of density decrease, while porosity increases. Mechanical properties including tensile strength, modulus of elasticity, and bending strength decreased, while the hardness of the alloy increases. The calculation of acoustic parameters such as the speed of sound (c), impedance (z) and radiation coefficient (R) has decreased. Moreover, sound intensity (dB), natural frequency (Hz) and damping capacity also decrease with increasing tin composition. Hence, tin bronze alloy Cu20wt.%Sn is the recommended raw material for the manufacture of gamelan instruments through the sand casting method.
    Źródło:
    Archives of Foundry Engineering; 2021, 21, 1; 137-145
    1897-3310
    2299-2944
    Pojawia się w:
    Archives of Foundry Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Acoustic Features of Filled Pauses in Polish Task-Oriented Dialogues
    Autorzy:
    Karpiński, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/176845.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    filled pauses
    paralinguistics
    dialogue
    acoustic properties
    Polish
    Opis:
    Filled pauses (FPs) have proved to be more than valuable cues to speech production processes and important units in discourse analysis. Some aspects of their form and occurrence patterns have been shown to be speaker- and language-specific. In the present study, basic acoustic properties of FPs in Polish task-oriented dialogues are explored. A set of FPs was extracted from a corpus of twenty task- oriented dialogues on the basis of available annotations. After initial scrutiny and selection, a subset of the signals underwent a series of pitch, formant frequency and voice quality analyses. A significant amount of variation found in the realisations of FPs justifies their potential application in speaker recognition systems. Regular monosegmental FPs were confirmed to show relatively stable basic acoustic parameters, which allows for their easy identification and measurements but it may result in less significant differences among the speakers.
    Źródło:
    Archives of Acoustics; 2013, 38, 1; 63-73
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Speech Intelligibility Test for Polish Language – Relation to the Acoustic Properties of Classrooms and Comparison to Other Languages
    Autorzy:
    Radosz, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/177319.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    speech intelligibility
    classroom
    school
    room acoustics
    Opis:
    Numerous studies have shown that teachers often speak louder in classrooms because of the acoustic properties of the spaces. To improve the acoustics in classrooms, it is necessary to develop relevant acoustic criteria. Existing evaluation scales for parameters of room acoustics have been developed on the basis of studies of adults for a variety of languages (e.g. Dutch and English). One of the issues still not fully recognized is the effect of the respondents’ language and age on the results of speech intelligibility tests. The aim of the study was to recognize the possibility of applying some international guidelines for room acoustics developed on the basis of adult studies to classrooms in Polish schools. This paper presents a study of the speech intelligibility of Polish-speaking children (10–13 years old) in conjunction with parameters of room acoustics. It also compares studies of speech intelligibility for other languages. The study confirmed a relationship between the results of speech intelligibility tests and speech transmission index STI for classrooms with varied acoustics. It also showed that the results of Polish word test are similar to results of English tests (Anderson, Kalb, 1987; Jacob et al., 1990).
    Źródło:
    Archives of Acoustics; 2018, 43, 1; 129-135
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Experiments and FE Analyses on Airborne Sound Properties of Composite Structural Insulated Panels
    Autorzy:
    Wawrzynowicz, A.
    Krzaczek, M.
    Tejchman, J
    Powiązania:
    https://bibliotekanauki.pl/articles/177722.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    acoustic properties
    composite structural insulated panel
    sound insulation
    finite element method
    steady state analysis
    transient analysis
    Opis:
    Airborne acoustic properties of composite structural insulated panels CSIPs composed of fibre- magnesium-cement facesheets and expanded polystyrene core were studied. The sound reduction ratings were measured experimentally in an acoustic test laboratory composed of two reverberation chambers. The numerical finite element (FEM) model of an acoustic laboratory available in ABAQUS was used and verified with experimental results. Steady-state and transient FE analyses were performed. The 2D and 3D modelling FE results were compared. Different panel core modifications were numerically tested in order to improve the airborne sound insulation of CSIPs.
    Źródło:
    Archives of Acoustics; 2014, 39, 3; 351-364
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of ultrasound assist during hot air drying on properties of dried apple crisps
    Autorzy:
    Banaszak, J.
    Pawłowski, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/185565.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ultrasound drying
    compression test
    acoustic emission
    apple
    material properties
    suszenie ultradźwiękowe
    test kompresji
    emisji akustycznej
    jabłko
    właściwości materiału
    Opis:
    In this paper the influence of high power airborne ultrasound on drying biological material (Lobo apple) properties is considered. Apple samples were dried convectively at 75 ◦C and air flow of 2 m/s with and without ultrasound assist at 200W. During experiments, sun-drenched and not sun-drenched part of fruits were considered separately to show, how the maturity of the product influences dry material properties. Dried apple crisps in a size of small bars were subjected to compression tests during which acoustic emission (AE) was used. Analysis of AE and strength test results shows that correlations between received acoustic signals and sensory attributes (crispness, brittleness) of dried apples can be found. It was noted that ultrasound improved fruit brittleness in comparison with pure convective processes, where fruit maturity determines a kind of destruction and behaviour of dried apple crisps.
    Źródło:
    Chemical and Process Engineering; 2018, 39, 3; 263--270
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of properties of expanded graphite - polymer porous composite by acoustic emission method
    Badanie właściwości porowatych kompozytów grafit ekspandowany - polimer metodą emisji akustycznej
    Autorzy:
    Berdowski, J.
    Berdowska, S.
    Aubry, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/351501.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    compressed expanded graphite
    polymerization
    carbonization
    composite membrane
    acoustic emission
    sprasowany grafit ekspandowany
    polimeryzacja
    zwęglanie
    membrana kompozytowa
    emisja akustyczna
    Opis:
    The purpose of this paper was to investigate the physical and mechanical properties of compressed expanded graphite (CEG) and their porous derivatives after impregnation, polymerization; and carbonization by the use of acoustic emission method (AE). The mechanical and structural characteristics of compressed expanded graphite and their three groups of porous composites after each technological process are presented and discussed. The measurements of acoustic emission parameters in these materials were carried out at wide range of frequency of the waves (0.1÷2.5 MHz). The changes of two of parameters: - AE pulses counts rate and spectrum distribution of AE waves - are presented in this paper. The analysis of the respective parameters AE also gives possibility to determine the micro- and macro structural changes of materials at different levels of technological processes. Applications of these materials as catalysts with high specific surface make them very interesting subject of study. Also compressed expanded graphite composite membranes prepared from furfuryl alcohol polymers are promising for gas separation.
    Cel pracy stanowiło zbadanie przy użyciu metody emisji akustycznej (EA) fizycznych i mechanicznych właściwości sprasowanego grafitu ekspandowanego (SGE) i jego porowatych pochodnych kompozytowych, otrzymanych po procesach impregnacji, polimeryzacji i karbonizacji. Przedstawiono i przedyskutowano mechaniczne i strukturalne charakterystyki sprasowanego grafitu ekspandowanego i trzech porowatych kompozytów otrzymanych na jego bazie, po kolejnych procesach technologicznych. Pomiary parametrów zarejestrowanych sygnałów EA w tych materiałach wykonano w szerokim przedziale częstotliwości emitowanych w materiale fal (0,1-2,5 MHz). W pracy przedstawiono zmiany dwu z tych parametrów: szybkości zliczeń impulsów i rozkładu widmowego emitowanych fal. Analiza poszczególnych parametrów emisji akustycznej stwarza możliwości określenia mikro- i makrostrukturalnych zmian w materiałach, wytworzonych na różnych etapach procesu technologicznego. Przewidywane szerokie zastosowanie tych materiałów jako katalizatorów, posiadających bardzo duże powierzchnie właściwe, czyni je niezwykle interesującym przedmiotem badań. Również bardzo perspektywiczne jest wykorzystanie kompozytowych membran z matrycą ze sprasowanego grafitu ekspandowanego, wypełnionego polimerem alkoholu furfurylowego. do separacji gazów.
    Źródło:
    Archives of Metallurgy and Materials; 2013, 58, 4; 1331-1336
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-8 z 8

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