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Metodika určování provenience zdrojových surovin pro výrobu historických vápenných malt
Martinec, Petr ; Ščučka, Jiří
Metodika byla vypracována v letech 2018-2021 v rámci řešení projektu NAKI II č. DG18P02OVV017 s názvem Historická krajina na pomezí Slezska a Moravy financovaného Ministerstvem kultury ČR. Metodika vychází z dlouholetých zkušeností prof. Ing. Petra Martince, CSc. a doc. Ing. Jiřího Ščučky, Ph.D. v oblasti geomateriálových a stavebně-materiálových analýz, které jsou prováděny v Ústavu geoniky AV ČR, v. v. i. ve spolupráci s odborníky z oborů archeologie a památkové péče. Metodika obsahuje komplexní postup při identifikaci potenciálních původních zdrojů surovin použitých pro výrobu hlavních materiálových komponent historických vápenných malt – kameniva a pojiva. Součástí metodiky jsou zásady odběru vzorků malt a srovnávacích horninových či zeminových vzorků in situ, postupy laboratorní materiálové analýzy kameniva, pojiva a hornin pro určení rozhodných srovnávacích parametrů, a také hlavní informační zdroje, z nichž lze při hledání surovinových zdrojů vycházet.
Plný tet:  PDF
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Composition and microstructure of plasters in convent of the Želiv Monastery (Czech Republic)
Rezek, P. ; Martinec, Petr ; Ščučka, Jiří ; Majstríková, T.
The paper deals with analyses of composition and structure of historic plasters from the convent building of the Želiv Monastery (Czech Republic). Composition and microstructure of plaster samples taken from the historic object have been assessed using both traditional and advanced analytical methods. The following techniques have been used for the assessment of binders and fine aggregates in plasters: optical microscopy of thin sections, mineralogical and petrographic analysis of separated components, infrared spectroscopy, and thermal analysis. Presented results show significant differences in character of the studied materials of varying age and demonstrate the effectiveness of the taken analytical approach.
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Velocity measurements on continuous micro water jet using fluorescent PMMA seeding particles
Zeleňák, Michal ; Ščučka, Jiří ; Souček, Kamil
The paper deals with application of optical diagnostic techniques for velocity\nmeasurements of continuous micro water jet. The combination of Particle image\nvelocimetry, Particle tracking velocimetry, Laser induced fluorescence and\nShadowgraphy methods have been applied together with the use of fluorescent\nPMMA seeding particles. An experimental closed water circuit was designed with\na low-pressure water pump, and a series of experiments was conducted to\nmeasure the velocity of seeding particles in the water jet flow below the diamond\nmicro-nozzle outlet. The basic principles of the methods used in experiments are\nalso described.
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Visualisation and quantitative analysis of flat continuous water jet structure
Ščučka, Jiří ; Zeleňák, Michal ; Foldyna, Josef ; Lehocká, D. ; Votavová, H.
The results of an experiment focused on the visualisation and structural analysis of flat continuous high-speed water jet used in descaling process are presented in this paper. The aim of the work was to test the applicability of the shadowgraph technique, combined with image processing and analysis methods, to visualise the water jet structure and analyse its main quantitative parameters. Volume percentage of water and air in the water jet structure, size of droplets and water bunches and other parameters were measured on digital images taken at various distances from the nozzle outlet. Knowledge of the water jet structure below the nozzle can facilitate an optimal setting of technological conditions of the water jetting with respect to the maximum disintegration effect on treated material. The described methods can also provide important information for development of new nozzles or entire water jetting tools for disintegration of materials.
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Surface strengthening of a stainless steel using pulsating water jet technology - evaluation by means of microhardness measurements
Hloch, Sergej ; Ščučka, Jiří ; Lehocká, D. ; Simkulet, V.
Results of an experiment focused on surface strengthening of AISI 304 stainless steel using pulsating water jet technology is presented in the paper. The tested material was subjected to the action of pulsating water jet under changing technological conditions (water pressure, traverse speed, stand-off distance, and diameter of nozzle orifice). Microhardness measurements at various distances from the created traces were applied for assessing the material strengthening. Based on the results, it can be stated that the dynamic effects of pulsating water jet on the tested steel samples cause the material deformations leading to the formation of a zone of strengthened material along the disintegrated area.
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Removal of polyurea spray coatings from the surface of cement concrete by water jet technology
Ščučka, Jiří ; Bódi, Z. ; Hlaváček, Petr ; Klich, Jiří ; Martinec, Petr ; Foldyna, Josef
The paper is focused on the removal of polyurea spray coatings from the surface of cement concrete by the water jet technology. A series of experiments was conducted to disintegrate a defined polyurea spray coat layer on the surface of cement concrete tiles using different configurations of the water jet system. The results of these experiments have confirmed that the continuous water jet was highly effective in removing the spray coat, causing no damage to the concrete substrate underneath. The partial experimental results have also indicated that this process can be used to produce an anti-skid finish on polyurea spray coatings applied onto horizontal structures.
Plný tet: UGN_0398599 -  DOC
Plný text: content.csg - DOC
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