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Wyszukujesz frazę "Jordan, R." wg kryterium: Autor


Wyświetlanie 1-6 z 6
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
Tytuł:
Validity of an Inertial Measurement Unit System to Assess Lower-limb Kinematics during a Maximal Linear Deceleration
Autorzy:
Jordan, Alastair R.
Carson, Howie J.
Wilkie, Brett
Harper, Damian J.
Powiązania:
https://bibliotekanauki.pl/articles/1339723.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
biomechanics
braking
IMU
stopping
Xsens
Opis:
This study examined the validity of an inertial measurement unit system for measuring lower-limb joint kinematics during linear decelerations. A male team athlete (age 36 years, stature 1.75 m, mass 80.0 kg) performed multiple linear decelerations, following 20 m runs at 50%, 75% and 100% self-perceived effort. Inertial measurement unit sensors were strapped to lower-limb segments and retroreflective markers were adhered to the lower-limbs for 3D optical motion analysis. Ground contact time, foot to centre of mass displacement (foot-COM), peak and minimum angle, mean angular velocity and range of motion at the ankle, knee and hip during the contact phases of each deceleration were determined. Measures were valid if a very large correlation (r ≥ 0.7) and small bias (effect size < 0.6) were evident. Following 50% effort, ground contact time, foot-COM and most hip and knee kinematics were valid. Ground contact time, foot-COM and knee flexion velocity and range of motion were valid following 75% efforts. Ground contact time and knee flexion velocity were valid following 100% effort. Therefore, the inertial measurement unit system tested can be used to assess temporal-spatial parameters during a deceleration regardless of the preceding effort, and hip and knee kinematics following low intensity running.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2021, 33, 1; 5-16
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Systemy wieloprocesorowe w automatyce i pomiarach
Multiprocesor systems in automatic control and measurements
Autorzy:
Jordan, A.
Bycul, R.
Forenc, J.
Myszkowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/158209.pdf
Data publikacji:
2004
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
klaster
przetwarzanie równoległe
metoda gradientu sprzężonego
metoda spekulacyjna
cluster
parallel processing
conjugate gradient method
speculative method
Opis:
Artykuł przedstawia konstrukcję homogenicznego systemu klaster - KETIM2, oraz dwa przykłady jego wykorzystania do rozwiązywania wybranych zagadnień z teorii sterowania i przybliżonych metod elektrotechniki. Pierwszym z nich jest równoległa implementacja algorytmu gradientu sprzężonego wykorzystywanego w teorii optymalizacji i metodzie elementów skończonych. Drugi przykład dotyczy równoległej analizy stanów nieustalonych w układach opisanych nieliniowym równaniem stanu. W tym drugim przypadku analizowano dynamikę silnika asynchronicznego pierścieniowego stosując metodę spekulacyjną. Przedstawiono również perspektywy zastosowań systemów wieloprocesorowych w technice pomiarowej.
The paper presents the construction of a homogenous cluster system - KETIM2 and two examples of its application for solving selected problems of control theory and approximate methods of electrical engineering. First of them is a parallel implementation of the conjugate gradient algorithm applied in the optimization theory and in the method of finite elements. The second example concerns parallel analysis of transient states in a dynamic system described by a nonlinear state equation. In the second case dynamics of asynchronous slip-ring motor was analysed appluing a speculative method. The perspectives of applications of multiprocessor systems in measurement technique were also presented.
Źródło:
Pomiary Automatyka Kontrola; 2004, R. 50, nr 10, 10; 16-20
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Economic modelling of the management of dredged marine sediments
Autorzy:
Harrington, J. R.
Murphy, J.
Coleman, M.
Jordan, D.
Debuigne, T.
Szacsuri, G.
Powiązania:
https://bibliotekanauki.pl/articles/184619.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
dredging
sediments
sediment management
economic modelling
economic impacts
economic analysis
beneficial use
Opis:
This paper presents and applies an economic model developed for the management of dredged marine sediments. The model predicts direct project costs and direct, indirect and induced economic impacts. The model is applied to analyse the economic aspect of the specific potential beneficial use of dredged sediment for land reclamation in an Irish context. The model results show the potential economic benefits to land reclamation of using dredged sediment including its value as a potential substitute for quarry based material and as an alternative to traditional offshore dredged sediment disposal, where appropriate. Analysis of other sediment management approaches including wetland creation, is also presented with the results for wetland creation indicating its potential, where appropriate, as a valuable alternative to offshore disposal. Indicative economic benefits are predicted by the model for the different dredge sediment management approaches analysed.
Źródło:
Geology, Geophysics and Environment; 2016, 42, 3; 311-324
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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