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    Wyświetlanie 1-21 z 21
    Tytuł:
    Application of non-uniform B-Splines of 2-nd order for description vertical distribution of sound speed in water
    Autorzy:
    Makar, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/332798.pdf
    Data publikacji:
    2009
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    hydroacoustics
    B-splines
    sound speed
    Opis:
    Modeling of the vertical distribution of the sound speed in water is useful during determination of the depth on the basis of the acoustic method, modeling refraction phenomena and determination the trajectory of the acoustic wave. For modeling 1D functions (vertical distribution of the sound speed) and 2D (surface of the sea bottom for hydrography) uniform B-Splines was used. In this paper description of uniform B-Splines and description and application of non-uniform B-Splines have been presented.
    Źródło:
    Hydroacoustics; 2009, 12; 133-140
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Positron annihilation and speed of sound in the systems containing beta-cyclodextrin
    Autorzy:
    Jerie, K.
    Baranowski, A.
    Burakowski, A.
    Gliński, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/146303.pdf
    Data publikacji:
    2010
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    sound speed
    compressibility
    positron annihilation
    cyclodextrin
    alcohol
    inclusion compounds
    Opis:
    Positron annihilation measurements were performed in aqueous solutions of beta-cyclodextrin, as well as in solid mixtures of this sugar with a long-chained alcohol, n-nonanol. Additionally, acoustic (sound speed, density and compressibility) experiments were done in aqueous beta-cyclodextrin and tert-butanol systems and in a three-component water-beta-cyclodextrin-tert-butanol system. The results show that in aqueous solution cyclodextrin does not form inclusive complexes with alcohol, while solid sugar-alcohol mixtures undergo slow changes in time, most probably caused by exchange of guest between interior and exterior of the host molecule.
    Źródło:
    Nukleonika; 2010, 55, 1; 65-68
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Research on the Method for Determining the Interaction of Cotton With the Working Bodies of Cotton Gins
    Autorzy:
    Sailov, Rahib Aqaqul
    Powiązania:
    https://bibliotekanauki.pl/articles/2200751.pdf
    Data publikacji:
    2022
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
    Tematy:
    fibre damage
    cottonseed
    sound speed
    cleaning process
    cotton raw material
    Opis:
    A theoretical regularity of the general behaviour of raw cotton as a porous medium in the technological processes of its mechanical processing has been substantiated for the first time. The speed of sound in a porous cotton medium has now been determined. The effect of additional force stresses inside the cotton medium caused by the filtration of the air component from cotton raw materials during the introduction of the working body, has been disclosed. A generalized equation that describes the force stress in a cotton medium when exposed to a variety of shapes of working bodies of cotton machines has been worked out. A method for calculating the damage to seeds and cotton fibers caused by their interactions with the working bodies of processing machines has been proposed. The resultant theory that describes the stress state of cotton raw materials during processing allows us to use it practically to solve all important issues pertaining to the damage of fiber and cotton seeds that occur by using technological solutions in primary processing of cotton operations.
    Źródło:
    Fibres & Textiles in Eastern Europe; 2022, 6 (151); 74--79
    1230-3666
    2300-7354
    Pojawia się w:
    Fibres & Textiles in Eastern Europe
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Algorithm for Computationally Efficient Imaging of Sound Speed in Conventional Ultrasound Sonography
    Autorzy:
    Karwat, Piotr
    Powiązania:
    https://bibliotekanauki.pl/articles/31339779.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    speed of sound
    ultrasound imaging
    computational complexity
    Opis:
    The speed of sound (SoS) in tissues reflects their mechanical properties and therefore can carry valuable diagnostic information. In conventional ultrasound sonography (US), however, this information is not readily available. Furthermore, since the actual SoS is unknown, image reconstruction is carried out using an average SoS value for soft tissues. The resulting local deviations from the actual SoS lead to aberrations in US images. Methods for SoS imaging in US therefore have the potential to enable the correction of aberrations in classical US. In addition, they could also become a new US modality. There are several approaches to SoS image reconstruction. They differ in terms of input data requirements, computational complexity, imaging quality, and the potential for signal analysis at the intermediate stages of processing. This article presents an algorithm with multi-stage processing and low computational complexity. The algorithm was verified through numerical simulations and phantom measurements. The obtained results show that it can correctly estimate SoS in layered media, which in most cases model the tissue structure well. With its computational complexity of O(n), the algorithm can be implemented in real-time ultrasound imaging systems with limited hardware performance, such as portable ultrasound devices.
    Źródło:
    Archives of Acoustics; 2023, 48, 4; 549-558
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An Improved Approximation for DIPPR-Based Predicting Speed of Sound in Long-Chained n-Alkanes
    Autorzy:
    Postnikov, E. B.
    Nedyalkov, Y. V.
    Polishuk, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/177788.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    n-alkanes
    isothermal compressibility
    speed of sound
    Opis:
    In this short communication, we revise a correlation for the saturated liquid isothermal compressibility based on the data available in DIPPR (Postnikov, 2016) which considers the molecular non-sphericity and addresses a problem of predicting speeds of sound in saturated long-chained alkanes. In addition, we correct a misprint appeared in the cited work and provide programming code used for the realisation of the proposed calculations.
    Źródło:
    Archives of Acoustics; 2018, 43, 3; 537-541
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Can DIPPR Database be Used for an Estimation of the Speed of Sound? A Case Study of Liquid Hydrocarbons
    Autorzy:
    Postnikov, E. B.
    Powiązania:
    https://bibliotekanauki.pl/articles/177811.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    speed of sound
    DIPPR
    reduced bulk modulus
    internal pressure
    Opis:
    The paper analyses a possibility of utilising the information which is contained in DIPPR database for a calculation of the speed of sound, which is absent there. As an example, liquid hydrocarbons are considered: n-hexane, 1-hexene, cyclohexane, cyclohexene, benzene, and 1-hexanols, as well as representatives of n-alkanes with various hydrocarbon chain lengths. It is shown that the Brelvi-O’Connell correlation for the reduced bulk modulus, supplied with the correlations for the internal pressure at the normal boiling temperature, results in the values having accuracy comparable with other DIPPR data for the region below the boiling point bounded by the values of the reduced density around pr ≈ 3.5. The source of errors originated from the Brelvi-O’Connell correlation for larger reduced densities is discussed.
    Źródło:
    Archives of Acoustics; 2016, 41, 4; 713-719
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Are the Heat Capacities of Liquids Calculated from Speeds of Sound and pρT Relationships Reliable? A Comparison with the Reference Values and a Discussion of the Uncertainties
    Autorzy:
    Szpaczek, Sylwia
    Marczak, Wojciech
    Powiązania:
    https://bibliotekanauki.pl/articles/31339956.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    speed of sound
    density
    compressibilt
    expansibility
    calorimetr
    elevated pressure
    Opis:
    Recent advances in the construction of speed of sound meters made high-accuracy routine measurements possible in laboratories non-specialized in physical acoustics. Reliable values of the isentropic compressibility can be obtained from speeds of sound and densities of liquids using the Laplace formula. Strict thermodynamic relationships connect the isentropic compressibility of a medium and its density as a function of temperature and pressure with the heat capacity. These relationships result from the principles of thermodynamics and require no approximations or molecular models. In this study, the heat capacities of twelve liquids: hydrocarbons, acetonitrile, and ionic liquids were calculated from the speeds and densities taken from the literature sources. The agreement of the calculation results with the reference heat capacities, either critical values or measured calorimetrically, was satisfactory. The relative uncertainty of the calculated heat capacities was rather conservatively estimated for 5%. If the measurement procedures were optimized for heat capacity determination, better results would be attained, with the uncertainty probably smaller than 1%. Thus, the speed-and-density method is a potential alternative to classical calorimetry.
    Źródło:
    Archives of Acoustics; 2022, 47, 4; 547-554
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Isotope effects on selected physicochemical properties of nitromethane and 1-pentanol
    Autorzy:
    Makowska, A.
    Szydłowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/148594.pdf
    Data publikacji:
    2006
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    deuterium
    isotope effects
    density
    viscosity
    speed of sound
    nitromethane
    1-pentanol
    Opis:
    Densities, kinematic viscosities, speed of sound and refractive indices of nitromethane and 1-pentanol and their deuterated derivatives CD3NO2 and C5H11OD were measured. The data obtained allowed to calculate molar volumes, dynamic viscosities, isentropic compressibilities and isobaric thermal expansion. Deuterium isotope effect on the selected physicochemical properties of both nitromethane and 1-pentanol has been determined. Large isotope effects characterizing density, viscosity and speed of sound are observed for nitromethane and much smaller for 1-pentanol. Isotope effects on molar volume are small both for nitromethane and 1-pentanol, but of the opposite sign. These observations are in agreement with the expectations.
    Źródło:
    Nukleonika; 2006, 51,suppl.2; 81-85
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Acoustic Nonlinearity Parameter B/A, Internal Pressure, and Acoustic Impedance Determined at Pressures up to 100 MPa for 1-Ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide
    Autorzy:
    Zorębski, E.
    Zorębski, M.
    Dzida, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/177585.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    nonlinearity parameter
    speed of sound
    high pressure
    ionic liquids
    internal pressure
    Opis:
    The nonlinearity parameter B/A, internal pressure, and acoustic impedance are calculated for a room temperature ionic liquid, i.e. for 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide for temperatures from (288.15 to 318.15) K and pressures up to 100 MPa. The B/A calculations are made by means of a thermodynamic method. The decrease of B/A values with the increasing pressure is observed. At the same time B/A is temperature independent in the range studied. The results are compared with corresponding data for organic molecular liquids. The isotherms of internal pressure cross at pressure in the vicinity of 70 MPa, i.e. in this range the internal pressure is temperature independent.
    Źródło:
    Archives of Acoustics; 2016, 41, 1; 59-66
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Pomiar prędkości dźwięku w cieczach metodą projekcji cienia fali stojącej w praktyce pokazowej w nauczaniu fizyki
    Measuring the speed of sound in liquids via a laser projection of the shadow of a standing wave in demonstrations in physics education
    Autorzy:
    Gawrysiak, Ignacy
    Powiązania:
    https://bibliotekanauki.pl/articles/32388076.pdf
    Data publikacji:
    2023
    Wydawca:
    Fundacja PSC
    Tematy:
    laser
    projection
    standing wave
    demonstration
    ultrasound
    speed of sound
    frequency
    wavelength
    Opis:
    Article puts under scrutiny a method of measuring the speed of sound in liquids via a laser projection of a standing wave. The range of application of the particular method was examined. A procedure of conducting the demonstration has been formulated based on the analysis of the impact of several parameters of the demonstration setup: particular vessel, depth of the liquid, position of the cone of light with regards to the stationary wave and particular sample used were all evaluated with regards to the quality of the demonstration as well as reliability of the measurement. Applying the procedure in order to quantitatively determine the concentration of a solution has been attempted, as well as usefulness of the method in a demonstration context – examined. As a conclusion, the potential of applying the method for demonstration has been discussed and an instruction for such demonstration has been produced.
    Źródło:
    Alcumena. Pismo Interdyscyplinarne; 2023, 2(14); 13-46
    2719-9851
    Pojawia się w:
    Alcumena. Pismo Interdyscyplinarne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Pozyskiwanie danych do tworzenia numerycznego modelu DNA
    Obtaining of data for digital sea bottom model
    Autorzy:
    Makar, A.
    Naus, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/130376.pdf
    Data publikacji:
    2003
    Wydawca:
    Stowarzyszenie Geodetów Polskich
    Tematy:
    pomiary hydrograficzne
    numeryczny model dna
    prędkość dźwięku w wodzie
    przechyły boczne i wzdłużne
    hydrographic surveys
    digital sea bottom model
    sound speed in water
    pitch
    roll
    Opis:
    W artykule przedstawiono proces pozyskiwania danych do tworzenia numerycznego modelu dna, zarówno morskiego, jak i akwenów śródlądowych. Ze względu na wykorzystywanie w pomiarach morskich tych samych systemów pozycyjnych, co w pomiarach lądowych, scharakteryzowano wyłącznie aparaturę do pomiaru głębokości oraz urządzenia do pomiarów towarzyszących. Przedstawiono technologię prowadzenia pomiarów, zakłócenia ruchu jednostki pomiarowej oraz możliwości zwiększenia dokładności pomiarów hydrograficznych.
    In this paper has been shown the process of obtaining of data for digital model of sea and inland bottom. Because of usage during sea surveys and terrestrial measurements these same positioning systems, there have been described only instruments for depth and accompanying measurements. There also have been presented the technology of surveying, movement disruptions of the sounding vessel and possibilities of increasing the accuracy of the hydrographic surveys.
    Źródło:
    Archiwum Fotogrametrii, Kartografii i Teledetekcji; 2003, 13a; 163-170
    2083-2214
    2391-9477
    Pojawia się w:
    Archiwum Fotogrametrii, Kartografii i Teledetekcji
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Relationships between acoustical properties and stiffness of soft tissue phantoms
    Autorzy:
    Gambin, B.
    Kruglenko, E.
    Byra, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/332049.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    soft tissue phantoms
    elastography
    ultrasound attenuation
    speed of sound
    Nakagami maps
    stiffness
    Opis:
    Polyvinyl-alcohol cryogel is commonly used for soft tissue phantom manufacture. The gel formation from an aqueous solution of polyvinyl-alcohol takes place during the freezing and thawing cycle. The aim of this work was to assess the degree of gel solidification, hence the material stiffness, by means of quantitative ultrasound. We manufactured three phantoms which differed in the number of freezing/thawing cycles. First, tissue phantoms were examined with an elastography technique. Next, we measured the speed of sound and the attenuation coefficient. What is more, the inter structure variations in phantoms were assessed with the Nakagami imaging which quantifies the scattering properties of the backscattered ultrasound echo. Obtained results confirmed the connection between the number of freezing/thawing cycles and the solidification p rocess. We d efined th e bo undary layer as a region which has a different structure than the sample interior. Next, for each phantom this layer was extracted based on a Nakagami parameter map. We calculated that the thickness of the boundary layer was lower in samples which were subjected to a larger number of freezing/thawing cycles.
    Źródło:
    Hydroacoustics; 2016, 19; 111-120
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study on thermodynamic properties of binary mixtures of diethyl carbonate with benzonitrile, benzaldehyde at different temperatures
    Autorzy:
    Sudhamsa, B.
    Babu, M. S.
    Narendra, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/411534.pdf
    Data publikacji:
    2014
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    binary mixtures
    excess adiabatic compressibility
    excess free length
    excess speed of sound
    Opis:
    The speed of sound and density in binary liquid mixture of diethyl carbonate + benzonitrile, + benzaldehyde have been determined at temperatures 298.15, 308.15 and 318.15 K over the whole composition range. The data have been utilized to estimate the excess adiabatic compressibility (βE), excess intermolecular free length (Lf E), excess speed of sound (uE) at the above temperatures. The excess values have been found to be useful in estimating the strength of the interactions in the liquid mixtures.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2014, 19, 1; 1-7
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of Ultrasonic Methods for Evaluation of High-Pressure Physicochemical Parameters of Liquids
    Autorzy:
    Kiełczyński, Piotr
    Ptasznik, Stanisław
    Szalewski, Marek
    Balcerzak, Andrzej
    Wieja, Krzysztof
    Rostocki, Aleksander J.
    Powiązania:
    https://bibliotekanauki.pl/articles/176703.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    ultrasonic methods
    speed of sound
    acoustic impedance
    surface tension
    thermal conductivity
    physicochemical properties
    Opis:
    An emerging ultrasonic technology aims to control high-pressure industrial processes that use liquids at pressures up to 800 MPa. To control these processes it is necessary to know precisely physicochemical properties of the processed liquid (e.g., Camelina sativa oil) in the high-pressure range. In recent years, Camelina sativa oil gained a significant interest in food and biofuel industries. Unfortunately, only a very few data characterizing the high-pressure behavior of Camelina sativa oil is available. The aim of this paper is to investigate high pressure physicochemical properties of liquids on the example of Camelina sativa oil, using efficient ultrasonic techniques, i.e., speed of sound measurements supported by paralel measurements of density. It is worth noting that conventional low-pressure methods of measuring physicochemical properties of liquids fail at high pressures. The time of flight (TOF) between the two selected ultrasonic impulses was evaluated with a cross-correlation method. TOF measurements enabled for determination of the speed of sound with very high precision (of the order of picoseconds). Ultrasonic velocity and density measurements were performed for pressures 0.1-660 MPa, and temperatures 3-30°C. Isotherms of acoustic impedance Za, surface tension σ and thermal conductivity k were subsequently evaluated. These physicochemical parameters of Camelina sativa oil are mainly influenced by changes in the pressure p, i.e., they increase about two times when the pressure increases from atmospheric pressure (0.1 MPa) to 660 MPa at 30°C. The results obtained in this study are novel and can be applied in food, and chemical industries.
    Źródło:
    Archives of Acoustics; 2019, 44, 2; 329-337
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wyznaczanie prędkości dźwięku w powietrzu przy użyciu karty muzycznej komputera
    Determination of speed of sound in air using a computers sound card
    Autorzy:
    Grodzicki, M.
    Adam, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/271307.pdf
    Data publikacji:
    2014
    Wydawca:
    Centralny Ośrodek Badawczo-Rozwojowy Aparatury Badawczej i Dydaktycznej, COBRABiD
    Tematy:
    prędkość dźwięku
    karta muzyczna
    komputer PC
    stanowisko edukacyjne
    speed of sound
    sound card
    personal computer
    educational stand
    Opis:
    Praca przedstawia sposób wykonania pomiaru prędkości rozchodzenia się dźwięku w powietrzu przy użyciu karty muzycznej komputera PC. Celem artykułu jest demonstracja prostego układu pomiarowego, umożliwiającego wyznaczenie prędkości dźwięku nawet w warunkach domowych, praktycznie bez nakładów finansowych. Zestaw pomiarowy składa się z komputera wyposażonego w kartę muzyczną, dwóch mikrofonów i głośnika. Generowane dźwięki są odbierane przez mikrofony i analizowane przez napisany na potrzeby projektu program komputerowy. Prezentowane doświadczenie może być wykorzystane w procesie dydaktycznym, np. do demonstracji na wykładach lub jako zestaw do wykonania ćwiczenia na I pracowni fizycznej. Autorzy prezentują stanowisko doświadczalne oraz ilustrują jego działanie wykonanymi pomiarami.
    The paper presents a measurement method for the speed of sound in air by using a PC sound card. The aim is to demonstrate a simple measurement system, which allows for measurement of the speed of sound even at home, and is available at minimal cost. The measurement setup consists of a PC with a sound card, two microphones and a speaker. The generated sounds are received by microphones and analyzed by the software specially elaborated for the project. The presented experiment can be used in the teaching process, e.g. as a demonstration at lectures or a setup for physical training lab. The authors present the experimental stand and illustrate its performance with standard measurements.
    Źródło:
    Aparatura Badawcza i Dydaktyczna; 2014, 19, 4; 333-340
    2392-1765
    Pojawia się w:
    Aparatura Badawcza i Dydaktyczna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the Interaction of Resonance And Bragg Scattering Effects for the Locally Resonant Phononic Crystal with Alternating Elastic and Fluid Matrices
    Autorzy:
    Yuan, B.
    Chen, Y.
    Jiang, M.
    Tang, S.
    He, M.
    Tu, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/177103.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    locally resonant phononic crystals
    effective speed of sound
    coupling band gaps
    underwater acoustic materials
    Opis:
    Three-dimensional (3D) locally resonant phononic crystals (LRPCs) are studied with the aim of optimising the sub-wavelength band gaps of such composites. By analysing their effective acoustic properties, it has been found that the effective acoustic speed of the composite will drop to zero when local resonance arise, and will increase monotonically when Bragg scattering effects occur. Moreover, if the matrix is a low-shear-speed medium, local resonators can significantly reduce the effective acoustic speed of the composite and, therefore, lower the frequency where Bragg scattering effects occur. Hence, a specific LRPC with alternating elastic and fluid matrices is proposed, whose resonance and Bragg gaps are already close in frequency. The fluid matrix behaves as a wave filter, which prevents the shear waves from propagating in the composite. By using the layer-multiple-scattering theory, the coupling behaviour of local resonance and Bragg scattering band gaps has been investigated. Both gaps are enhanced when they move closer to each other. Finally, a gap-coupled case is obtained that displays a broad sub-wavelength band gap. Such proposal excels at the application of underwater acoustic materials since the arrangement of structure can be handily adjusted for tuning the frequency of coupled gap.
    Źródło:
    Archives of Acoustics; 2017, 42, 4; 725-733
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    New low-cost method for determination of heating value of natural gas
    Nowe, tanie metody oznaczania wartości opałowej gazu ziemnego
    Autorzy:
    Rybitskyi, I.
    Karpash, O.
    Darvay, I.
    Karpash, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/299334.pdf
    Data publikacji:
    2011
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    wartość grzewcza
    gaz ziemny
    CO2
    prędkość akustyczna
    heating value
    natural gas
    speed of sound
    Opis:
    New method for heating value determination has been proposed earlier which lays in simultaneous measurement of carbon dioxide and nitrogen concentrations and speed of sound in natural gas and use of neural network utilized for calculation of heating value. Based on reference data bases application of the method allowed to achieve relative error of 2.6% for heating value determination. Afterwards additional investigation has been made aimed to exclude nitrogen concentration measurement, which also gave good accuracy of heating value determination. Special experimental setup has been developed for experimental verification of the method. Experimental setup included commercial ultrasonic device for speed of sound measurement, special carbon dioxide concentration meter, relative humidity and temperature measuring units. Numerous experiments were completed using the setup with subsequent natural gas chromatographic analysis. Analysis of the achieved results showed good accordance of the theoretical model with experimental data.
    W artykule zaproponowano nową metodę określania wartości grzewczej polegającą na równoczesnym pomiarze stężenia dwutlenku węgla i azotu, prędkości akustycznej gazu ziemnego i wykorzystania sieci neuronowych do obliczenia wartości grzewczej. Korzystając z metody opartej na bazie danych odniesienia uzyskano względny błąd 2,6%. Następnie przeprowadzono dodatkowe badanie ukierunkowane na oddzielenie pomiaru stężenia azotu, co również dało dokładny wynik pomiaru wartości cieplnej. Opracowano specjalny zestaw badawczy w celu przeprowadzenia doświadczalnej weryfikacji metody. Zestaw ten składa się z komercyjnego urządzenia ultradźwiękowego do pomiaru prędkości dźwięku, specjalny miernik stężenia dwutlenku węgla, jednostki do pomiaru wilgotności względnej i temperatury. Przeprowadzono równocześnie liczne eksperymenty za pomocą wspomnianego zestawu i analizę chromatograficzną gazu. Analiza uzyskanych wyników wykazała dobrą zgodność teoretycznego modelu z danymi doświadczalnymi.
    Źródło:
    Wiertnictwo, Nafta, Gaz; 2011, 28, 1-2; 333-338
    1507-0042
    Pojawia się w:
    Wiertnictwo, Nafta, Gaz
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    New instrument for measuring the velocity of sound in gases and quantitative characterization of binary gas mixtures
    Autorzy:
    Koturbash, T.
    Bicz, A.
    Bicz, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/114208.pdf
    Data publikacji:
    2016
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    ultrasonic measurement
    velocity of sound
    speed of sound
    natural gas
    time of flight
    characterization of gas mixture
    analysis of gas mixture
    Opis:
    A new instrument for precise measurements of velocity of sound in gases was developed and tested. The instrument implements improved velocity of sound measuring technique based on time-of-flight measurement of ultrasonic pulses. The instrument was developed primarily for conducting measurements in natural gas, it can operate in wide ranges of natural gas compositions as well as other gas mixtures with velocity of sound parameter in range of 200 to 500 m/s. The instrument allows conducting measurement of velocity of sound propagation in various gas mixtures with average repeatability of equal to ±1 cm/s at normal conditions. The accuracy of measurement depends on calibration conditions and approach, and has good agreement with theoretically calculated values. The instrument has a modular design of control unit and flow-through measuring chamber. The set of distinctive features and adjustable measuring parameters of the instrument allows further improving of applicability for other gases and gas mixtures and various measurement conditions. The instrument showed good performance in the task of quantitative characterization of binary gas mixtures by velocity of sound parameter.
    Źródło:
    Measurement Automation Monitoring; 2016, 62, 8; 254-258
    2450-2855
    Pojawia się w:
    Measurement Automation Monitoring
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Amorphous Dielectric Thin Films with Extremely Low Mechanical Loss
    Amorficzne cienkie warstwy dielektryczne z bardzo małą wielkością strat mechanicznych
    Autorzy:
    Liu, X.
    Queen, D. R.
    Metcalf, T. H.
    Karel, J. E.
    Hallman, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/353256.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    internal friction
    amorphous silicon
    elastic modulus
    speed of sound
    tunneling systems
    tarcie wewnętrzne
    krzem amorficzny
    moduł sprężystości
    prędkość dźwięku
    Opis:
    The ubiquitous low-energy excitations are one of the universal phenomena of amorphous solids. These excitations dominate the acoustic, dielectric, and thermal properties of structurally disordered solids. One exception has been a type of hydrogenated amorphous silicon (α-Si:H) with 1 at.% H. Using low temperature elastic and thermal measurements of electron-beam evap-orated amorphous silicon (α-Si), we show that TLS can be eliminated in this system as the films become denser and more structurally ordered under certain deposition conditions. Our results demonstrate that TLS are not intrinsic to the glassy state but instead reside in low density regions of the amorphous network. This work obviates the role hydrogen was previously thought to play in removing TLS in α-Si:H and favors an ideal four-fold covalently bonded amorphous structure as the cause for the disappearance of TLS. Our result supports the notion that α-Si can be made a “perfect glass” with “crystal-like” properties, thus offering an encouraging opportunity to use it as a simple crystal dielectric alternative in applications, such as in modern quantum devices where TLS are the source of dissipation, decoherence and 1/f noise.
    Wszechobecne niskoenergetyczne wzbudzenia są jednym z powszechnych zjawisk w amorficznych ciałach stałych. Wzbudzenia te dominują akustyczne, dielektryczne i termiczne właściwości strukturalnie nieuporządkowanych ciał stałych. Wyjątkiem jest rodzaj uwodornionego amorficznego krzemu (α-Si:H) o zawartości 1 at.% H. Na podstawie niskotemperaturowych badań własności sprężystych i termicznych krzemu amorficznego (α-Si) naparowanego wiązką elektronów wykazaliśmy, że w pewnych warunkach osadzania można wyeliminować TLS w tym układzie tak, że warstwy stają się gęstsze i strukturalnie bardziej uporządkowane. Uzyskane przez nas wyniki wskazują, że TLS nie są nieodłączną cechą stanu szklistego, ale lokują się w regionach o niskim zagęszczeniu sieci amorficznej. Praca niniejsza wyjaśnia, że wodór nie pełni roli w usuwaniu TLS w α-Si:H, jak dotąd sądzono, i wskazuje na idealną czterokrotnie kowalencyjnie związaną amorficzną strukturę jako przyczynę znikania TLS. Nasz wynik potwierdza koncepcję, że z α-Si można wytworzyć “doskonałe szkło” o “podobnych do krystalicznych” właściwościach, oferując w ten sposób zachęcającą możliwość wykorzystania go alternatywnie jako prosty krystaliczny dielektryk w takich aplikacjach jak w nowoczesne urządzenia kwantowe, gdzie TLS są źródłem dyssypacji dekoherencji i szumu 1/f.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 1; 359-363
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fractal Analysis of Noise Signals of Sampo and John Deere Combine Harvesters in Operational Conditions
    Autorzy:
    Boroujeni, Farzad Mahdiyeh
    Maleki, Ali
    Powiązania:
    https://bibliotekanauki.pl/articles/176317.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    sound
    combine
    fractal dimension
    engine speed
    sliding window
    Opis:
    Combine harvesters are the source a large amount of noise in agriculture. Depending on different working conditions, the noise of such machines can have a significant effect on the hearing conditio of drivers. Therefore, it is highly important to study the noise signals caused by these machines and find solutions for reducing the produced noise. The present study was carried out is order to obtain the fractal dimension (FD) of the noise signals in Sampo and John Deere combine harvesters in different operational conditions. The noise signals of the combines were recorded with different engine speeds, operational conditions, gear states, and locations. Four methods of direct estimations of the FD of the waveform in the time domain with three sliding windows with lengths of 50, 100, and 200 ms were employed. The results showed that the Fractal Dimension/Sound Pressure Level [dB] in John Deere and Sampo combines varied in the ranges of 1.44/96.8 to 1.57/103.2 and 1.23/92.3 to 1.51/104.1, respectively. The cabins of Sampo and John Deere combines reduced and enhanced these amounts, respectively. With an increase in the length of the sliding windows and the engine speed of the combines, the amount of FD increased. In other words, the size of the suitable window depends on the extraction method of calculating the FD. The results also showed that the type of the gearbox used in the combines could have a tangible effect on the trend of changes in the FD.
    Źródło:
    Archives of Acoustics; 2019, 44, 1; 89-98
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Prędkość propagacji fali dźwiękowej w pniach olszy czarnej Alnus glutinosa (L.) Gaertn. w zależności od temperatury
    Temperature dependence of sound wave propagation in as a diagnostic tools for healthy and rotten black alder (Alnus glutinosa (L.) Gaertn.) tree trunks
    Autorzy:
    Orzechowski, M.
    Budniak, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1317727.pdf
    Data publikacji:
    2013
    Wydawca:
    Instytut Badawczy Leśnictwa
    Tematy:
    drzewa
    olsza czarna
    Alnus glutinosa
    pnie drzew
    fale dzwiekowe
    propagacja fal
    predkosc dzwieku
    czynniki atmosferyczne
    temperatura powietrza
    alder
    speed of sound wave propagation
    temperature
    internal decay
    impulse hammer
    Opis:
    The aim of this study was to determine how thermal conditions affect the speed of sound wave propagation, in trunks of living alder Alnus glutinosa (L.) Gaertn. trees. This method in practiced when diagnosing the presence of internal decay in standing trees. Field work was carried out four times at different temperatures (+13°C, +3°C, -7°C and -16°C) using an Impulse Hammer. There was a significant correlation between the thermal conditions and the speed of sound wave propagation. Therefore, temperature must be taken into account to correctly diagnose tree health and timber quality.
    Źródło:
    Leśne Prace Badawcze; 2013, 74, 4; 285-291
    1732-9442
    2082-8926
    Pojawia się w:
    Leśne Prace Badawcze
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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