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Methodology for determining the provenance of raw materials for the production of historical lime mortars
Martinec, Petr ; Ščučka, Jiří
The methodology was developed in the years 2018-2021 as part of the solution of the project Historical landscape on the border of Silesia and Moravia financed by the Ministry of Culture of the Czech Republic (project No. DG18P02OVV017, NAKI II programme). The methodology is based on the long-term experience of prof. Petr Martinec, Ph.D. and Jiří Ščučka, Ph.D. in the field of geomaterial and building material analyses, which are carried out at the Institute of Geonics of the Academy of Sciences of the Czech Republic in cooperation with experts from the fields of archaeology and monument care. The methodology includes a comprehensive procedure for identifying potential original sources of raw materials used for the production of the main material components of historical lime mortars – aggregate and binder. The methodology also includes: principles of sampling mortars and comparative rocks or soils in situ, procedures for laboratory material analysis of aggregates, binders and rocks to determine relevant comparative parameters, and the main information sources that can be used when searching for sources of raw materials.\n
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.
Fulltext: content.csg -  DOC
Plný tet: UGN_0398599 - DOC
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