Josef Blazek

Technical University of Košice · Department of Aviation Technical Studies

Presented article briefly explain the history and the success of applied magnetism, that has been the main focus of research and development scientist group originally seated at Slovak Air Force Academy of Milan Rastislav Štefánik in Košice. The group was focused on measuring of magnetic field since 1982 when they develop the first digital magnetom...

Magnetic position sensors are popular in industrial and automotive applications since they are robust, resistant to dust and oil and they can be cheap. However, precise magnetic position sensors can achieve 0.015 % accuracy and 10 nm resolution. The maximum achievable range is about 20 m. DC magnetic position sensors are using a permanent magnet as...

One of the perspective methods for the magnetic field measurement is the methodology based on the GMI effect measurement. The improvement of the sensor is in term of the sensor sensitivity and the wide-band measurement range in comparison to the commercially available magnetometers. For the evaluation of the impedance of the sample the lock-in ampl...

Magnetic position and speed sensors are rugged and durable. While DC magnetic sensors use permanent magnets as a field source and usually have only mm or cm range, inductive sensors use electromagnetic induction and they may work up to a distance of 20 m. Eddy current inductive sensors equipped with magnetoresistive sensors instead of inductive coi...

The article deals with the measurement, visualization and analysis of the magnetic field in the 3D space around a small quadcopter. The measurements were realized in the very low frequency (VLF) range, since this range is interesting because of the possible detection of the drone also in the fully automated flight mode (without telemetry transmissi...

The article points to the effects of the ambient noise and its possible influences on quantification of the inherent switching field noise of magnetic microwires. Based on the observed effects, an advanced methodology was developed to quantify the impact of the ambient noise. During measurements a multi-channel system with applied correlation metho...

Some of the frequent reasons of titanium implant failures in human body are incorrect biomechanical interac-tions within the tissue-implant interface and inammatory processes arising around the implant's application area. For both processes, it is crucial to locate them and intervene in time. One of the monitoring possibilities of the mentioned pro...

The article deals with the noise analysis of magnetic sensors using Allan variance. In comparison with the standard variance, based on the variations around the average value, Allan variance provides a measure of the behavior of the variability of a quantity as it is averaged over different measurement time periods, which results in a better conver...

Current trends in modernization and miniaturization of ferroprobe sensors lead to replacement of amorphous ribbon cores with magnetic microwires. The miniaturization often causes degradation in the parameters of sensors, so, considering measurement of weak magnetic fields, it is necessary to explore noise parameters, temperature drift and stability...

In the field of magnetic sensors, magnetic microwires with positive magnetostriction are the materials of the future. Their mechanical and magnetic properties render them ideal materials for applications in aeronautics. A single microwire with a 40 jj.m diameter and a length of 10 mm is capable of capturing information about tensile stresses, magne...

Magnetic microwires have been rediscovered due to a number of the unusual magnetic properties and their potential applications. The paper concerns glass-coated magnetic microwires composed of a ferromagnetic metallic core with a diameter of 0.6 - 30 jj.m and of a glass coat with a thickness of 2 - 20 jj.m. The fabrication process and magnetic prope...

We have studied the stress dependence of the switching field in the glass-coated FeNbSiB microwire. The stress dependence can be tailored by properly choosing the frequency of exciting magnetic field. At low frequencies, the switching field is weakly dependent on the mechanical stress, which is ideal for sensors of magnetic field or temperature. In...

This paper deals with the possibilities of contactless stress measuring inside a material. Conventional strain gauge measuring methods cover surface stress measuring, however measuring inside in material is widely limited. Magnetic microwires give us the ability to create a build-in sensor inside the material without its structure violation. Moreov...

The idea of intelligent sensoric implant which enables to scan parameters from the human body wireless comes from analysis of studies descrbing reasons of implants rejection or loosening. Inflamations and incorrect biomechanical load are offen the reasons for surgery, where implant has to be removed or replaced. Presented study shows a concept of i...

The article deals with so called multi-position static tests of magnetometer. This method is commonly used for Inertial Measurement Unit (IMU) accelerometer calibration. The goal of these tests is to approximate static conversion characteristics of 3-axis IMU magnetometer and to determine additive and multiplicative constants for x, y, z channels o...

Vema-04.1, a four channel magnetometer, which is currently being developed at Department of Aviation Technical Studies, has an innovative design of sensor's electronic circuits, based on complex programmable logic device (CPLD). By change in CPLD program, we are able to set different magnetometer operating modes, directly influencing its sensitivit...

The paper presents basic information about special induction sensors for heavy industrial conditions, namely a strong electromagnetic disturbance. As the major parameters are the extreme geometrical width of sensing and precise measurement of the time moment for transition of magnetic markers. For this sensor the gradient differential concept with...

We are dealing with the temperature and frequency dependencies of the switching field in the glass-coated FeNbSiB microwire. Both dependencies can be described in terms of two contributions to the switching mechanism: magnetoelastic and structural relaxation. We show that by properly setting the frequency of the measurement, it is possible to vary...

We report on the development of new generation of magnetic relaxation sensors based on soft magnetic melt-spun ribbons with the composition Fe 63Co21B15Cu. The as-quenched amorphous alloy was subjected to thermomagnetic heat treatment in order to obtain sensor cores with optimized magnetic properties. The relaxation characteristics obtained for the...

Melt-spun Fe₆₃ Co₂₁ B₁₅Cu ribbons were annealed at temperatures between 573 K and 623 K in longitudinal and transverse-magnetic field in order to prepare a representative set of relaxed amorphous and partially crystallized samples having uniaxial anisotropy. The optimal magnetic characteristics for the relaxation se...

We present here the improved method for sensing the domain wall propagation direction in the Sixtus–Tonks-based experiments. The new method allows us to recognize not only the direction of the domain wall propagation but also the domain wall nucleation in between the sensing coil or multiple nucleation of two domain wall at both ends of studied wir...

This paper investigates the influence of the collector and diffuser effect of forehead discs on cylindrical ferromagnetic cores and the magnetic properties within the models of rod and dumbbell-type sensors and exciters core especially.

The task to extend the range and dynamic resolution of a proven digital magnetic field sensor is solved. The specific sensor-type requirements are followed when selecting the suitable material from among nanocrystalline ribbons of the FeNbCuBSi Finemet family. The materials are tested by measuring the hysteresis loops, the longitudinal incremental...

An objective of this article is the relationship between the signal sensitivity, the noise sensitivity and the distribution of turns of winding on any chosen axis-symmetric core. The analytical study originates from Faraday Induction law and Nyquist theorem. Different windings were compared with respect to their physical properties.

This contribution deals with concrete results of application of eigenmodes magnetization theory for bodies of chosen geometrical shapes. It is possible to define the eigenmodes of magnetization physically by a constant effective permeability all over the dimension of a body and thereby, the magnetization of the body is formed the same way as the ge...

The problem of bodies with non-homogeneous magnetization is investigated by the finite element method. The result of numerical simulation is a response matrix. Eigenvalues of the response matrix are proportional to the effective permeabilities of single modes of magnetization. The way of calculation of the magnetic induction using the orthogonal ex...

We present in this work some new theoretical results concerning an influence of the shape of core on the development of magnetization. As a special case the rotary symmetric objects with non-homogeneous magnetization were investigated. The shape of core was optimized on the basis of various practical criteria.

This paper is a contribution to the special fluxgate sensors. It provides an additional mathematical model of a versio of a sensor already published (D. Praslicka, IEEE Trans. Magn., 30 (1994) 934). It is a sensor fearturing an amorphous ferromagnetic alloy core. As the output signal characteristics of rectangular waveform have a pulse width propor...