Temat: harmonic component - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: A Simulation for Detecting Nonlinear Echoes from Microbubbles Packets
Autorzy:: Ali, M. G. S.
Elsayed, N. Z.
Eid, E. A.
Powiązania:: https://bibliotekanauki.pl/articles/177697.pdf
Data publikacji:: 2015
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: microbubbles packets
harmonic component
acoustic
radial dynamic
pressure spectrum
Opis:: This work presents a simulation of the response of packets of microbubbles in an ultrasonic pulse-echo scan line. Rayleigh-Plesset equation has been used to predict the echo from numerically obtained radial dynamics of microbubbles. Varying the number of scattering microbubbles on the pulse wave form has been discussed. To improve microbubble-specific imaging at high frequencies, the subharmonic and second harmonic signals from individual microbubbles as well as microbubbles packets were simulated as a function of size and pressure. Two different modes of harmonic generation have been distinguished. The strength and bandwidth of the subharmonic component in the scattering spectrum of microbubbles is greater than that of the second harmonic. The pressure spectra provide quantitative and detailed information on the dynamic behaviour of ultrasound contrast agent microbubbles packet.
Źródło:: Archives of Acoustics; 2015, 40, 2; 151-157
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Coupled modelling for machine tool structural optimization
Autorzy:: Sulitka, M.
Sindler, J.
Susen, J.
Powiązania:: https://bibliotekanauki.pl/articles/99670.pdf
Data publikacji:: 2014
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: mutlibody model
component coupling
finite element
harmonic analysis
Opis:: Effective machine tool design needs to take into account various kinematic configurations and possible combinations of structural parts, which meet the requirements of both the structural properties on one hand and technology and cost limitation on the other hand. Prior to a detailed developing a certain machine tool structure, an expert based decision on the machine tool conception needs to be performed. A high number of design variants should be explored in a short time. Fulfilling those demands leads to developing a machine tool modular models, enabling easy changing the kinematic configuration or various structural parts. In the paper the techniques for effective component coupling and model order reduction using mode truncation or Krylov subspace based technique for creating the machine tool coupled models are introduced. Case studies considering real machine tool structures are given. High quality of Krylov subspace reduction technique in connection with multipoint constraint surface coupling is shown both in terms of dynamic properties of the reduced multibody model and a very low time demands at the same time.
Źródło:: Journal of Machine Engineering; 2014, 14, 3; 21-34
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Comparison of Two Model Coupling Methods for Joint Identication
Autorzy:: Susen, J.
Sulitka, M.
Sindler, J.
Janota, M.
Powiązania:: https://bibliotekanauki.pl/articles/99775.pdf
Data publikacji:: 2015
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: machine tool
mutlibody model
component coupling
harmonic analysis
Opis:: An experimental identification of joint dynamic properties requires accurate models of the joined bodies and an appropriate model coupling method. The bodies to be coupled can be described by their mass, stiffness and damping matrices (M, K, C) or by receptance matrices. Each approach has its advantages and disadvantages. The receptance matrix method requires a high number of measurements. However the measured data can be used directly and no model identification is needed. The experimental identification of the M, K, C matrices feasible for creating precise coupled models is difficult. Therefore, an approach based on a verified FE model can be employed. The two methods of model identification and coupling are discussed using a case study of two bolted beams. Several ways of the receptance matrices measurement simplification and their influence on the accuracy of the results are studied. The effect of noise, measured FRF peak accuracy and data filtering on the resulting coupled receptance matrix is studied as well. The results obtained by the receptance matrix method are compared to the results obtained by the method of coupling the verified FE models. It has been found that the method based on coupling the verified M, K, C matrices proves to be a more reliable approach, which will allow a more precise joint dynamic model identification in the next step.
Źródło:: Journal of Machine Engineering; 2015, 15, 1; 58-70
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Data mining system for air quality monitoring networks
Autorzy:: Czechowski, P.
Badyda, A.
Majewski, G.
Powiązania:: https://bibliotekanauki.pl/articles/204820.pdf
Data publikacji:: 2013
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: air pollutants
data quality analysis
data mining
estimation
exploratory methods
harmonic
principal component analysis
statistical tests outliers
influential
leverage observations
analytical software system
programming
Eco Data Miner
EDM
Winsorized mean
Cook
Mahalanobis distance
DFITS
COVRATIO
Opis:: The use of quantitative methods, including stochastic and exploratory techniques in environmental studies does not seem to be sufficient in practical aspects. There is no comprehensive analytical system dedicated to this issue, as well as research regarding this subject. The aim of this study is to present the Eco Data Miner system, its idea, construction and implementation possibility to the existing environmental information systems. The methodological emphasis was placed on the one-dimensional data quality assessment issue in terms of using the proposed QAAH1 method - using harmonic model and robust estimators beside the classical tests of outlier values with their iterative expansions. The results received demonstrate both the complementarity of proposed classical methods solution as well as the fact that they allow for extending the range of applications significantly. The practical usefulness is also highly significant due to the high effectiveness and numerical efficiency as well as simplicity of using this new tool.
Źródło:: Archives of Environmental Protection; 2013, 39, 4; 123-147
2083-4772
2083-4810
Pojawia się w:: Archives of Environmental Protection
Dostawca treści:: Biblioteka Nauki

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