Wyniki wyszukiwania - Biblioteka Nauki

1

An attempt to describe heart attacks via continuum damage mechanics

100%

Życzkowski M.

|

2000

|

tom Vol. 52, nr 4-5

889-910

EN

In an earlier paper the author expressed the evolution equations of classical continuum damage mechanics in terms of unit dissipated power and proposed an extension to biological materials in vivo, adding a term describing the recovery. In the present paper an analogy with evolution of the coronary artery disease is established. If we denote by S (relative stenosis) one minus the ratio of current luminal area to the initial area, then the condition S = 1 at a certain point of the artery means complete blockage at this point resulting in a heart attack (myocardial infarction). This corresponds to the condition of critical state D = 1 in damage mechanics, where D denotes a scalar measure of damage. Making use of this analogy, an evolution equation for S is proposed, with unit dissipated power replaced by unit power of flow in individual cross-sections of coronary arteries and, subsequently, by the heart power. Further, another evolution equation describes the required heart power in terms of external loadings acting on the organism as a whole. Numerical integration of the evolution equations proposed makes it possible to distinguish the loadings leading to a myocardial infarction from those subject to recovery. Also, the description of stable and unstable angina pectoris is discussed and illustrated by numerical examples.

2

On the optimal design of viscoplastic bars under combined torsion with bending

63%

Życzkowski M. , Cegielski E.

|

2002

|

tom Vol. 54, nr 5-6

751-770

EN

The governing equation for viscoplastic simultaneous torsion and bending of a prismatic bar is derived. Then a certain particular closed-form solution of this equation is found; it corresponds to an elliptic cross-section with the ratio of semi-axes depending on the bending-to-torsion ratio. This solution proves to be optimal if the optimization constraint is imposed on initiation (nucleation) and growth of material damage and if the material properties conform to the Huber-Mises-Hencky failure hypothesis.

3

Localization of Magnetical Disturbance Along Fiber Optic

51%

Szustakowski M. , Ciurapiński W. , Życzkowski M.

|

2001

|

tom Vol. 22

275-284

EN

Algorithm for digital processing of disturbance signal in passive homodyne Sagnac interferometer based on 3x3 coupler was shown. Computer simulations for the algorithm contains quadrature, demodulation and mechanical disturbance localization along fiber optic with experimental data was performed.

4

Zintegrowany, optoelektroniczny system ochrony obiektów rozległych infrastruktury krytycznej

45%

Życzkowski M. , Szustakowski M. , Ciurapiński W. , Pałka N. , Kastek M.

|

2010

|

tom R. 86, nr 10

157-160

PL

Niniejsze artykuł przedstawia opis koncepcji użycia wyselekcjonowanych podzespołów optoelektronicznych, opracowanych elementów integracji hardwarowo/softwarowych, i ich badań oraz metod syntezy uzyskanych informacji w celu monitorowania stref ochrony przestrzennej obiektów rozległych z możliwą automatyczną detekcją zagrożeń. W artykule przedstawiono proces identyfikacji czujników optoelektronicznych dostępnych na rynku światowym przeznaczonych do monitorowania wielokilometrowych obszarów pod względem metodyki ich wyboru w zależności od wymagań funkcjonalnych ochrony. Podstawową funkcjonalnością ujawnioną w przedstawionej problematyce, a ujmującą wyniki badań prowadzonych przez zespół jest możliwość syntezy niepowiązanych technicznie danych z różnych czujników w jeden interfejs informacyjny. Abstract. The pape

EN

The paper presents the concept of multispectral protection system for perimeter protection of stationary and moving objects. The system consists of an active ground radar as well as a thermal and visible cameras. The radar allows the system to find potential intruders and to control an observation area for system cameras. The multisensor construction of the system ensures significant improvement of intruder detection probability and reduction of false alarms. A final decision of system is worked out using image data. A method of data fusion used in the system has been presented. The system works under control of FLIR Nexus unit. The Nexus offers complete technology and components to create network-based, high-end integrated systems for security and surveillance applications. Based on unique “plug and play” architecture, the system provides unmatched flexibility and simplistic integration of sensors and devices in TCP/IP networks. Using a graphical user interface it is possible to control sensors and monitor streaming video and other data over the network, visualize the results of data fusion process and obtain detailed information about detected intruders over a digital map. System provide high-level applications and operator workload reduction with features such as sensor to sensor cueing from detection devices, automatic e-mail notification and alarm triggering.