Browsing Ústav fyziky by Author "Kusák, Ivo"
Now showing items 1-15 of 15
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Acoustic non-destructive testing of high temperature degraded concrete with comparison of acoustic impedance
Dvořák, Richard; Chobola, Zdeněk; Kusák, Ivo (MATEC Web of Conferences, 2018-10-30)The paper is focused on non-destructive measurement of high temperature degraded concrete test specimens of three mixtures different by the use of coarse aggregate. Testing is done by ultrasonicpulse velocitymethod and ... -
Carbon admixtures influence on the electrical properties of slag mortars focusing on alternating conductivity and permittivity
Luňák, Miroslav; Kusák, Ivo; Chobola, Zdeněk (Elsevier, 2016-08-01)New materials based on alkali-activated slag mortars may be an important contribution of applied research, which strives to offer the use of waste materials as a full replacement for the currently used binders and explores ... -
Change in the Sensory Properties of Alkali Activated Slag Mortars
Kusák, Ivo; Luňák, Miroslav (Elsevier, 2020-01-27)This article describes how the test slag mortars with addition of carbon powder COND 986 by electrical impedance spectroscopy measurement methods and their extensions in the form of using ZNC vector network analyzer with ... -
Comparison of results of impedance spectroscopy methods with results of impact-echo method in investigation of high-temperaturedegraded concrete
Luňák, Miroslav; Kusák, Ivo; Štefková, Daniela (Elsevier, 2016-08-01)The growth in the transport industry results in more accidents, which often include fire in locations with the concrete structures, which also effects its lifetime and its functionality. After any case of fire loading it ... -
Electric conductivity changes in geopolymer samples with added carbon nanotubes
Kusák, Ivo; Luňák, Miroslav; Rovnaník, Pavel (Elsevier, 2016-08-01)By incorporation of nanotubes to the current composite materials, their properties can be significantly improved. Carbon nanotubes can act as filler, which minimizes the air gaps content in the matrix. The denser structure ... -
Electrical and Self-Sensing Properties of Alkali-Activated Slag Composite with Graphite Filler
Rovnaník, Pavel; Kusák, Ivo; Bayer, Patrik; Schmid, Pavel; Fiala, Lukáš (MDPI, 2019-05-16)The electrical properties of concrete are gaining their importance for the application in building construction. In this study, graphite powder was added to alkali-activated slag mortar as an electrically conductive filler ... -
Electrical properties of alkali-activated slag composite with combined graphite/CNT filler
Rovnaník, Pavel; Míková, Maria; Kusák, Ivo (IOP Publishing Ltd., 2017-10-25)Alkali-activated industrial by-products such as blast furnace slag are known to possess properties which are comparable to or even better than those observed for ordinary Portland cement. The combination of alkali-activated ... -
Impact of graphite admixture on electrical properties of alkali-activated slag mortars
Kusák, Ivo; Luňák, Miroslav; Rovnaník, Pavel (EDP Sciences, 2017-05-24)One of the objectives of the applied research's striving consists in providing the users with new slag-mortar-based materials. Basic research, in its turn, aims at examining the newly created materials from the viewpoint ... -
Impedance spectroscopy measurement of metakaolin-based alkali-activated building materials
Kusák, Ivo; Luňák, Miroslav; Mizerová, Cecílie; Rovnaník, Pavel (IOP Publishing, 2020-12-18)Cement-containing as well as cement-free building materials are regarded as dielectrics. Therefore, electrically conducting admixtures are to be added to them in order to increase their electrical conductivity. Steel or ... -
Low-frequency noise measurements used for quality assessment of GaSb based laser diodes prepared by molecular beam epitaxy
Chobola, Zdeněk; Luňák, Miroslav; Vaněk, Jiří; Hulicius, Eduard; Kusák, Ivo (Faculty of Electrical Engineering and Information Technology of the Slovak University of Technology, 2015-08-01)The paper reports on a non-destructive method of reliability prediction for semiconductor lasers diodes GaSb based VCSE. Transport and noise characteristic of forward biased were measured in order to evaluate the new MBE ... -
Monitoring of concrete hydration by electrical measurement methods
Kusák, Ivo; Luňák, Miroslav; Chobola, Zdeněk (Elsevier, 2016-08-01)Analysis of impedance spectra of inhomogeneous materials is a part of the impedance spectroscopy which is still waiting for its development. Materials having higher electric resistance values (over 500 kohm) can be considered ... -
Nonlinear Elastic Wave Spectroscopy with MLS Perturbation Signal
Carbol, Ladislav; Martinek, Jan; Kusák, Ivo; Kucharczyková, Barbara (Výzkumný ústav stavebních hmot,a.s., 2016-05-31)The article describes a test procedure based on the fundamental principle of Nonlinear Elastic Wave Spectroscopy. Without integration of all test stages into one automated measurement station and without Maximum Length ... -
On the effect of addition of carbon nanotubes on the electric conductivity of alkali-activated slag mortars
Kusák, Ivo; Luňák, Miroslav (IOP Publishing, 2017-10-18)This paper presents basic electric properties of laboratory prepared alkali-activated composite materials on the basis of finely ground granular high furnace slag to which various quantities of carbon nanotubes (CNT) have ... -
Self-sensing performance of metakaolin geopolymer with carbon nanotubes subjected to repeated compressive loading
Mizerová, Cecílie; Rovnaník, Pavel; Kusák, Ivo; Schmid, Pavel (IOP Publishing, 2021-12-21)Alkaline activated binders showing enhanced piezoresistive properties have recently attracted increased interest in research of their application in smart self-sensing components. This study is focused on metakaolin ... -
Self-Sensing Properties of Fly Ash Geopolymer Doped with Carbon Black under Compression
Mizerová, Cecílie; Kusák, Ivo; Topolář, Libor; Schmid, Pavel; Rovnaník, Pavel (MDPI, 2021-08-04)The development of smart materials is a basic prerequisite for the development of new tech-nologies enabling the continuous non-destructive diagnostic analysis of building structures. Within this framework, the piezoresistive ...