Search

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

It is generally acknowledged that there is a correlation between the incidence of ultraviolet burden diseases and overexposure of the body to ultraviolet radiation (UVR). The main goals of our study were to determine the level of knowledge of college students in regard to the effects of UVR, to educate them about it, and finally to urge them to improve their personal protection against the harmful effects of UVR. We performed an educational-questionnaire study of UVR in 2003, 2005, and 2008 years. Responses of 841 students from Jessenius Faculty of Medicine in Martin (JFM), University of Zilina, and St. Elizabeth College of Health and Social Work (SEC) in Bratislava showed a higher level of knowledge in students at JFM and Univ. of Zilina following their education, as compared to those students from SEC. There was little difference in responses to questions related to the protection against UVR. A lower level of knowledge in all groups of students was shown in 2005. Nevertheless, all respondents significantly increased their level of protection against UVR during the years of the study and the number of those visiting solaria decreased. A weak relationship between the knowledge of students and their protection skills against UVR was found, indicating that a complex reason might be involved. This study highlights the importance of providing education that is systematic and longterm to university students in Slovakia (future doctors, bioengineers and nurses). Moreover, this study brings new insights on the surveillance and protection against the harmful effects of UVR to prospective patients.

This paper discusses about minimally invasive techniques to detect the single leg fracture in special type of artificial heart valve called Bjork Shiley Convexo - Concave (BSCC). The fracture affects the outlet strut of these artificial heart valve and it is needed to detect it. For this purpose the electromagnetic methods based on eddy current testing were used. The coils are excited in the selected range of the frequencies for identification of the fractures in the outlet strut. The fractures occurring in BSCC heart valve and their numerical simulations are described. The results obtained with a prototype setup are presented and they demonstrate the usefulness of described techniques for detection of the outlet strut fractures in BSCC artificial heart valve.

The paper deals with the biomaterials nondestructive testing using electromagnetic methods. The eddy current testing and electromagnetic - acoustic transducer methods are analyzed and applied for evaluation of conductive prosthetic materials. The defects detection results achieved by simulations and measurements using both methods are compared and discussed.

The paper deals with material electromagnetic non-destructive testing (eNDT) with emphasize on eddy current testing (ECT). Various modifications of ECT sensing are compared and discussed from the desired detected signal characteristics point of view. Except of the optimization of usual probe coils arrangements for the concrete applications, the new magnetic sensors as giant magneto-resistance (GMR) and spin dependent tunneling (SDT) are presented. The advanced ECT sensors are characterized by their sensitivity, frequency range and sensor dimensions

The paper presents a general overview of recent developments in the eddy-current non-destructive evaluation. Basic principle of the eddy-current non-destructive testing is explained and possible applications of the method in noninvasive evaluation of conductive materials are summarized. Actual issues of research and development in this field are discussed. A novel method for depth evaluation of a detected crack using eddy-current testing signals is proposed

This paper describes the use of electromagnetic methods of non-destructive testing for detecting of inhomogeneities presence in a prosthetic replacement with focus on strut fractures in prosthetic heart valves. In the first part of this paper there are described a basic principle of eddy current testing, heart valve replacement and materials which are usually used for it. The experimental part contains description of simulated problem, obtained simulation results and their interpretation for use in medicine.

At present a non-destructive testing of conducting materials becomes very important one in connection with monitoring and control of strategic technical facilities, e.g. nuclear power plants. There are more methods of material testing and evaluation and every of them has its advantages and disadvantages. Recently the electromagnetic methods are in increasing interest. There are many ways of conducting material testing. One of them often used utilises investigation of eddy currents induced in the surface layer by means of a proper coil. The arrangement is very simple and inexpensive but it offers only local information on cracks and other inhomogeneities in the thin surface layer. On the other hand there exist a method based on an electromagnetic – acoustic transducer (EMAT), which is able to generate and detect acoustic wave in a conducting body in a contact-less way. The present paper deals with a survey of EMATs for investigation of thin metalliclayers by means of Lamb waves. The new design of generation coil is presented.

The paper deals with the cerebral arterial system investigation by means of electrical modelling and simulations. The main attention is paid to the brain arterial circle malformations (stenoses and aneurysms) and their determination and evaluation by computer-aided methods as tools of a non-invasive diagnostics. The compensation possibilities of brain arterial circle in case of presence of concrete arterial malformations are modelled and simulated. The simulation results of brain arteries blood pressures and volume flow velocities time dependences are presented and discussed under various health conditions.

The contribution deals with the modelling and simulation of human brain haemodynamics using analogous electromagnetic systems characteristic especially propagation properties of distributed parameters circuits. The cascade connection of analogical transmission line elements represents the vascular tree both from the point of the parameters and the topology as well. In the paper there are presented simulation examples of the healthy cerebral system mainly in the big arteries in comparing with the pathologically changed ones. The various degrees of stenosis are considered for the simulations of blood pressure and blood flow velocity and the results are compared with the healthy arteries. According to the last investigations the pathological deformations of brain arteries are th most frequently reasons of deaths in the world. The stenoses or aneurysms change the physical properties of arteries and they follow insufficient vascularisation of the brain. These computer-aided non-invasive methods together with the non-invasive experimental techniques represent a helpful tool both for the diagnostics and the treatment of vascular pathological deformations.

The paper deals with the basic principles of operation and with the utilization possibilities of phased array (PA) in materials nondestructive testing (NDT). The first part deals with description of PA arrangement modes, which enable to generate, focus and steer the ultrasonic beem. The second part deals with the description of electromagnetic acoustic transducer PA operation. The last part deals with the description of the utilization of PA in nondestructive testing of conductive materials and the advantages of PA utilization in inhomogeneous materials NDT.

In the paper the principles and application of nondestructive evalution by both electromagnetic acoustic transducer (EMAT) and the eddy current (EC) methods are introducted. The ultrasonic testing (UT) and the electromagnetic nondestructive testing (NDT) are presented with their fundamental properties and the experimental results concerning the defect of conducting object characterization are shown.

The paper deals with the interaction of electromagnetic and acoustic processes in a conducting medium in presence of an external magnetic field. The electromagnetic excitation of acoustic wave similarly as acoustic excitation of electromagnetic wave is described. The practical utilization consisting in contactless acoustic wave generation and detection is demonstrated.

The paper deals with the modelling and the simulation of physiological fluid systems laying emphasise on the human vascular system. The presented simulation method has been developed as a helpful tool for the computer-aided non-invasive diagnostics of living bodies. Using the electromechanical analogy between physiological and electrical values the introduced method makes possible the description and 3D representation of the non-linear characteristics of the human haemodynamics as well. The simulation procedure and the obtained results verified by the experiment enable to visualize all physiological and pathophysiological states of the human vascular system.

The paper deals with the modelling and simulation of physiological fluid systems, especially the human vascular system. The described procedures are based on the electron~echanical analogy making possible the application of electromagnetic theory. The physiological fluid segments are represented by the analogical equivalent electric transmission line sections. According to this analogy the electromagnetic propagation characteristics describe the mechanical properties of flowing fluids. The introduced modelling and simulation procedures enable to describe and visualize all states of dynamics of physiological processes, especially of the human haemodynamics. The obtained results serve as an important tool for non-invasive computer aided diagnostics.