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Wyszukujesz frazę "Jordan, P. M." wg kryterium: Autor


Wyświetlanie 1-4 z 4
Tytuł:
Acoustic propagation in inhomogeneous fluids: regularization via the introduction of fine particles
Autorzy:
Jordan, P. M.
Powiązania:
https://bibliotekanauki.pl/articles/38440473.pdf
Data publikacji:
2020
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
inhomogeneous fluids
Laplace transform
particle-laden flow
singular surface theory
Opis:
It is shown, using analytical methodologies, that the velocity field blow-up suffered by vertically ascending acoustic waves in an isothermal atmosphere can be eliminated via the introduction of fine particles. Assuming the inhomogeneous generalization of the particle-laden flow model known as the (linearized) Marble–Thompson model-1, it is established that bounded, exponentially decreasing, shock amplitudes can be obtained provided the mass fraction of particles exceeds a critical value, for which an exact expression is derived. Lastly, supporting numerical results are presented, special cases are discussed, and possible follow-on studies are noted.
Źródło:
Archives of Mechanics; 2020, 72, 1; 59-73
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of the Effect of Production Parameters on Mechanical Properties of Sintered Steels Using ANOVA
Autorzy:
Sułowski, M.
Jordan, A.
Czarski, A.
Matusiewicz, P.
Powiązania:
https://bibliotekanauki.pl/articles/356320.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
powder metallurgy
analysis of variance (ANOVA)
Opis:
The object of the study was to assess the influence of selected production parameters of sintered Fe-Mn-Cr-Mo-C steels i.e. chemical composition, sintering temperature, sintering atmosphere and heat treatment on the following mechanical properties: impact toughness, hardness of the surface, tensile strength, bend strength after static tensile tests. In the investigations, the general linear model (GLM) of the multivariate analysis of variance ANOVA was used. All assumptions of ANOVA, i.e. randomization of the experiment, the normality of the residuals, equality of variance at different levels have been fulfilled and verified. The predictive strength of the constructed models expressed by the adjusted determination coefficient (R2adj) is at medium or large level – R2adj is in the range from 41.46% to 76.97%. This work is focused mainly on the ANOVA methodology. A wide physical interpretation of the results will be possible after the optimization of the ANOVA models used.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2A; 571-576
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Numerical Approach to Calculate the Radiation Efficiency of Baffled Planar Structures Using the Far Field
Autorzy:
González-Montenegro, M. A.
Jordan, R.
Lenzi, A.
Arenas, J. P.
Powiązania:
https://bibliotekanauki.pl/articles/176303.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
propagating matrix
far field
sound power
structural finite element analysis
Opis:
A numerical method is developed for estimating the acoustic power of any baffled planar structure, which is vibrating with arbitrary surface velocity profile. It is well known that this parameter may be calculated with good accuracy using near field data, in terms of an impedance matrix, which is generated by the discretization of the vibrating surface into a number of elementary radiators. Thus, the sound pressure field on the structure surface can be determined by a combination of the matrix and the volume velocity vector. Then, the sound power can be estimated through integration of the acoustic intensity over a closed surface. On the other hand, few works exist in which the calculation is done in the far field from near field data by the use of radiation matrices, possibly because the numerical integration becomes complicated and expensive due to large variations of directivity of the source. In this work a different approach is used, based in the so-called Propagating Matrix, which is useful for calculating the sound pressure of an arbitrary number of points into free space, and it can be employed to estimate the sound power by integrating over a finite number of pressure points over a hemispherical surface surrounding the vibrating structure. Through numerical analysis, the advantages/disadvantages of the current method are investigated, when compared with numerical methods based on near field data. A flexible rectangular baffled panel is considered, where the normal velocity profile is previously calculated using a commercial finite element software. However, the method can easily be extended to any arbitrary shape. Good results are obtained in the low frequency range showing high computational performance of the method. Moreover, strategies are proposed to improve the performance of the method in terms of both computational cost and speed.
Źródło:
Archives of Acoustics; 2014, 39, 2; 249-260
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
One step 3D printing of surface functionalized composite scaffolds for tissue engineering applications
Autorzy:
Kotlarz, M.
Jordan, R.
Wegner, E.
Dobrzyński, P.
Neunzehn, J.
Lederer, A.
Wolf-Brandstetter, C.
Pamula, E.
Scharnweber, D.
Powiązania:
https://bibliotekanauki.pl/articles/306484.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
druk 3D
PLGA
węglan wapnia
właściwości powierzchniowe
3D printing
calcium carbonate
amphiphilic poly(2-oxazoline)
degradation
surface properties
Opis:
A successful approach widely used in materials science to adapt approved materials to specific applications is to design their surface properties. A main challenge in this area is the development of processing routes enabling for a simple but efficient surface design of complex shaped geometries. Against this background, this work aimed at the implementation of self-assembly principles for surface functionalization of 3D-printed poly(lactic-co-glycolic acid) (PLGA)-based constructs with macro- and microporous geometries via precision extruding deposition. Methods: Three-component melts from PLGA, CaCO3 and amphiphilic polymers (poly(2-oxazoline) block copolymer) were printed and their bulk and surface properties were studied. Results: Melts with up to 30 mass % of CaCO3 could be successfully printed with homogeneously distributed mineral particles. PLGA degradation during the printing process was temperature and time dependent: the molecular weight reached 10 to 15% of the initial values after ca. 120 min of heat exposure. Filament surfaces from melts containing CaCO3 show an increasing microroughness along with increasing CaCO3 content. Surface roughness and amphiphilic polymer content improve scaffold wettability with both factors showing synergistic effects. The CaCO3 content of the melts affected the inner filament structure during in vitro degradation in PBS, resulting in a homogeneous mineral particle-associated microporosity for mineral contents of 20 mass % and above. Conclusions: These results provide novel insights into the behavior of three-component melts from PLGA, CaCO3 and amphiphilic polymers during precision extruding deposition and show for the first time that self-assembly processes can be used to tailor scaffolds surface properties under such processing conditions.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 2; 35-45
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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