University of Defense Brno

Brno, Czech Republic

University of Defense Brno

Brno, Czech Republic
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Biolkova V.,Brno University of Technology | Bajer J.,University of Defense Brno | Biolek D.,University of Defense Brno | Biolek D.,Brno University of Technology
Radioengineering | Year: 2011

Two novel four-phase voltage-output oscillators are proposed. These circuits can also be utilized as quadrature oscillators with floating outputs. Each oscillator employs two DO-CIBA (Differential Output- Current Inverter Buffered Amplifier), two grounded capacitors, and four or three resistors. Independent control of the oscillation frequency (OF) and oscillation condition is practicable in both oscillators. Real measurements on the oscillator specimens confirm the ability of easy OF control and extra low THD, which is less than 0.07%.

Bajer J.,University of Defense Brno | Lahiri A.,36 B | Biolek D.,University of Defense Brno | Biolek D.,Brno University of Technology
Radioengineering | Year: 2011

The paper deals with a pair of current-mode sine-wave oscillator circuits. Both these circuits are implemented using positive second-generation current conveyors (CCII+). The principle of the first oscillator is based on a conventional Wien-bridge network. However, this implementation suffers from the use of a floating capacitor, which can be unacceptable in the case of on-chip integration. This drawback is solved in the second variant via a slight modification of the Wien-bridge network, which then allows the use of all capacitors grounded. The modified circuit version was manufactured by means of the socalled diamond transistors, which play the role of CCII+ active building blocks. The circuit behavior was analyzed theoretically, with particular emphasis on the identification of real effects and their elimination, and subsequently verified experimentally. The experimental results are included in the paper.

Biolek D.,University of Defense Brno | Biolek D.,Brno University of Technology | Biolkova V.,Brno University of Technology | Kolka Z.,Brno University of Technology
Radioengineering | Year: 2012

The method of immediate analysis of periodic steady states in switched DC-DC converters operating in the continuous current mode is described. The initial conditions, which correspond to the periodic steady state, are found in the first step. They are used consequently for the conventional transient analysis. A special SPICE model of the converter finds automatically these initial conditions, which are then available within the transient analysis. The method works both for the well-known behavioral models of switched converters and also for models which employ complex nonlinear SPICE models of semiconductor switches.

Pitschmann V.,Oritest Ltd | Kobliha Z.,University of Defense Brno | Tusarova I.,Oritest Ltd | Bartova L.,Czech Technical University | And 2 more authors.
Chemical Industry and Chemical Engineering Quarterly | Year: 2014

A new simple and sensitive detection tube to detect hydrogen cyanide in the air has been developed. The detection tube is based on the reaction of hydrogen cyanide with 4-nitrobenzil to form a violet colored product. The reaction takes place on a carrier made of a composite material, which was prepared by pelletization of a mixture of microcrystalline cellulose and MgO. The detection tube can detect hydrogen cyanide in the air in the range of concentrations 0.1-100 mg m-3 based on visual evaluation (by naked eye) of the change of indication layer coloring and comparison with etalon. The detection limit is 0.05 mg m-3. The detection tube is highly selective and sufficiently stable during storage.

Beyr P.,University of Defense Brno
ICMT 2015 - International Conference on Military Technologies 2015 | Year: 2015

Geopolitics is steered along pipelines nowadays. Those words should be attributed to Henry Kissinger. Geopolitics is presented as a scientific discipline bound to explain effect of geography factors on the politics and history of nations. This simplified explanation shall be complemented by natural wealth of certain region. Otherwise the reason to put pipelines would be uncertain. And vice versa, this is a reason why our soldiers shall be educated in this area of knowledge. This article would like to contribute this education with the focus on the recognition of mineral deposits location. The Author rejected any imagination to provide the individual list of mineral deposits only. The natural rules on the mineral deposits development inside Earth crust have been presented. The mineral deposits of strategic significance have been manifested. The article is based on the lectures of geology in the framework of civil engineering as the starting point. The mineral deposits development shall be considered as a follow up study, hence a connection between civil engineering and geopolitics. Finally, an example based on the previous explanation, the presentation of the natural wealth of African continent has been submitted. © 2015 University of Defence.

Hoskovcova M.,University of Defense Brno | Dubina P.,VTUO Military Technical Institute of Protection Brno Division | Halamek E.,University of Defense Brno | Kobliha Z.,University of Defense Brno
Analytical Letters | Year: 2011

Construction of Detehit (nerve-agent detector), a colorimetric biosensor of nerve agents, enables its utilization for selective analysis of nerve agents based on the different ability of nucleophilic reagents to reactivate enzyme-inhibitor complexes in the phase before dealkylation. For this purpose mono- and bispyridinium aldoximes, common in treatment of nerve agent poisoning, are used. For a positive identification of a pair of organophosphates, a neural network analysis was used. The analysis was processed based on spectral data of the intensity of color changes of the surface of a cotton cloth reaction zone with immobilized and stabilized enzyme acetylcholinesterase. Color changes are based on Ellman's reaction. Intensity of these changes depends on activity of the enzyme after inhibition and reactivation of enzyme-inhibitor complex. The following nerve agents were identified: sarin, soman, tabun, cyclosarin, VX, and R-33. © Taylor & Francis Group, LLC.

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