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The article deals with the design of an electrical model of variable segments of a non-symmetrical tree of small arteries This model can be used to simulate the blood pressure and flow. Peripheral arterial resistance changes are modelled by an exponentially dependent resistor. By modulating the capacitor value, we can model the arterial wall properties which depend on the arterial pressure. Simulations are performed in which vasoconstriction and vasodilation were modelled by varying the transmural pressure. As a result, we can observe the changes in the blood pressure for each arterial generation.

A three-dimensional numerical modeling is an appropriate tool for analyzing and estimating of the physical material properties in general. This article is focused on the modeling of inhomogeneities in the austenitic stainless steels, which are used as biomaterials. These materials can interact with a biological tissue inside a human body. In addition, these steels are also widely used in many industry and transport sectors. Three fundamental inhomogeneity models were created for this purpose. The models correspond to the real inhomogeneities that may occur in these materials (fatigue and stress-corrosion cracks). Third model is the artificial one, used as the reference sample. The all models are investigated by the eddy current testing method which is theoretically well-known and described for investigation of conductive biomaterials. The results of numerical simulation are presented and discussed in this paper.

This article deals with non-destructive evaluation of austenitic stainless steels, which are used as the biomaterials in medical practice. Intrinsic magnetic field is investigated using the fluxgate sensor, after the applied plastic deformation. The three austenitic steel types are studied under the same conditions, while several values of the deformation are applied, respectively. The obtained results are presented and discussed in the paper.

This paper deals with nondestructive evaluation of concrete conductive biomaterials that are nowadays widely used on the field of biomedicine. The study focuses on detection ability of a commercial magnetic field sensor for detection of residual magnetic field of inspected biomaterials. The gained results are presented and discussed in this paper.

The article deals with the non-destructive evaluation of austenitic stainless steels. Various specimens are inspected under the same conditions. Residual weak magnetic field of the biomaterials is investigated. Commercial fluxgate sensor is used for the inspection. The gained results are presented and discussed in the paper.

The article deals with the non-destructive evaluation of conductive biomaterials. Various austenitic steel specimens are inspected under the same conditions. Residual weak magnetic field of the biomaterials is investigated. Commercial fluxgate sensor is used for the inspection. The gained results are presented and discussed in the paper. Biomaterials applied in the form of implants are under long-term mechanical stresses.

Modelling ofbloodflowinvesselsoffersauseful toolfor vascular systemexamination. Propagationof bloodpressure and blood flow pulses are analyzed in the present paper. The pulses shapes are significantly influenced by their reflections at vessels inhomogeneities. The whole body arterial model is used for different phenomena investigation. Influence of waves' reflections on their profiles is examined. Consequences of vessels bifurcations, stenosis and sclerosis are simulated and the simulated results are compared with experimental data taken by means of PPG.

Thepaper proposes utilizationof eddy current inspection fordetection ofdefects intheartificialheart valve. Artificial heart valves are prosthetic replacements which are used if the function of the natural heart valve is limited. A special type of prosthetic heart valve replacements is the Bj¨ ork Shiley convexo-concave (BSCC) heart valve. The fractures of the BSCC artificial heart valve usually affect the outlet strut. If the fracture of the strut is not detected in time the patient can die of heart attack. Detection of the fracture in the outlet strut is the concern here. Experimental measurements are performed in order to evaluate the detection capability of the technique and the sensitivity of response signal to dimensional parameters of a fracture. A BSCC heart valve prototype having the electromagnetic characteristics of the Co-Cr (Hayness 25) alloy is inspected with a probe. A non-conductive defect is positioned in the outlet strut and its dimensions are varied. The probe is positioned above the centre of the crack and the frequency of exciting signal is changed in a wide range. The presented results demonstrate that the sweep frequency technique can enhance eddy current inspection of a defect in BSCC heart valve.

This paper proposes a unique idea for enhancing sizing ability in eddy current nondestructive testing. A detected crack is inspected using several probes driven at the same exciting frequency but producing different eddy current distributions. Two probes are utilized for the purpose in the paper. The crack signals obtained with the two probes are linearly superposed and a unique value of the ratio of superposition is extracted from the mixed signals. Numerical investigations and experimental verification reveal that the value provides clear indications of the crack's depth. In addition, the depth of a notch five times as deep as the standard depth of penetration was well evaluated using the method.

The paper deals with modelling and simulation of a human brain arterial system using analogous electromagnetic systems, especially propagation characteristics of electric transmission lines. Cascade connection of analogous equivalent transmission line elements represents a vessel tree concerning both the electromagnetic parameters and the topology. Elec- tromechanical analogy between physiological and electromagnetic values enables a description and following simulation of a cerebral haemodynamics by means of electric circuits analogous relations. The vascular dynamics modelling and simulation represents an important tool for the non-invasive computer-aided investigation of the brain arteries pathological deformations. The presented simulation results give the information about the blood dynamic characteristics also in the case of cerebral arterial stenoses or aneurysms under various stenosis degrees. The obtained results can provide helpful knowledge for the practical treatment of the basic brain arteries.

The present paper deals with the utilization of the electromagnetic-acoustic transducer (EMAT) for the non-destructive testing of conducting materials. The principle of the EMAT consists in the interaction of the electrodynamic structure of materials with an external electromagnetic (EM) field under influence of a bias magnetic field. It offers the possibility to generate an acoustic mode of the penetrating EM wave with the slow velocity and the attenuation of the acoustic wave or on the other hand to detect the EM wave due to its radiation from the surface of a conducting sample. The main advantage of the EMAT is the contactless generation and detection of the acoustic wave, or the acoustic mode of EM wave in a wide range of frequencies and temperatures. The special properties of EMAT’s driving and detecting devices are presented in the paper.

The paper deals with identification of real biomaterial's cracks using electromagnetic non-destructive sensing. Advanced types of the magnetic sensors are used for this purpose. New modular eddy current probe is used for the evaluation. Harmonic excitation is used for the eddy currents induction. The real biomaterial stress corrosion cracks are inspected. Gained results are discussed and presented in the paper. The main aim of the article is to compare the sensitivity of the various magnetic sensors at the same conditions.

Many accidents leads to organ damages, bone loss or cause the failure of organ systems. Biomaterials have their application in orthopedic, vascular or in dental implants to augment and replace the loss. Many of prosthetic replacements are implanted for a long time so their correct function need to be control. Currently we have a few non- destructive testing technologies available to characterize the various features that may arise during or after the implantation. Depending on the different types of biomaterials, different features interested, different purpose of testing, the different non-destructive testing technologies should be used. This article deals with fracture detection in Bjőrk-Shiley Convexo Concave (BSCC) artificial heart valve where the damage of the valve can endanger the human life.