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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.
2015 - English
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.
Keywords:
pulsating water jet; stainless steel; surface strengthening; microhardness
Available in digital repository of the ASCR
Surface strengthening of a stainless steel using pulsating water jet technology - evaluation by means of microhardness measurements
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 ...
Geomythology: a useful tool for geoconservation and geotourism purposes
Kirchner, Karel; Kubalíková, L.
2015 - English
The relationship between the geosciences and myths is studied by geomythology which is understood as an explanation of the geological and geomorphological features using the supernatural forces and beings. The geomythological aspect can be regarded in relation to cultural, historical and spiritual meaning or value of geodiversity and it can be included into the holistic concept of geotourism. The article briefly discuss the reasons why geomythological aspect could be used for geoconservation and geotourism purposes and it presents several examples (especially geosites and geomorphosites) from the Czech Republic where the geomythological value is (or can be) used for these purposes.
Keywords:
geosites; geomorphosites; Bohemian-Moravian Highland
Available in digital repository of the ASCR
Geomythology: a useful tool for geoconservation and geotourism purposes
The relationship between the geosciences and myths is studied by geomythology which is understood as an explanation of the geological and geomorphological features using the supernatural forces and ...
Study of quality of nine aluminium alloys surfaces created using abrasive waterjet
Klichová, Dagmar; Klich, Jiří; Gurková, Lucie
2015 - English
The article focuses on the normalized method of measurement and evaluation of a surface texture created using the abrasive waterjet. It detects selected amplitude parameters of a roughness profile providing a form of a quantified description of properties of a surface topography. It studies the change in quality of machined surfaces created by the abrasive waterjet in nine selected materials of aluminium alloys when changing the traverse speed. Studied samples were measured by an optical profilometer MicroProf FRT and further analyzed with the SPIP software.
Keywords:
surface roughness; abrasive waterjet; aluminium alloy
Available in digital repository of the ASCR
Study of quality of nine aluminium alloys surfaces created using abrasive waterjet
The article focuses on the normalized method of measurement and evaluation of a surface texture created using the abrasive waterjet. It detects selected amplitude parameters of a roughness profile ...
Measurement and analysis of abrasive particles velocities in AWJ
Zeleňák, Michal; Foldyna, Josef; Martinec, Petr; Cárach, J.; Gurková, Lucie; Nováková, Daria
2015 - English
Abrasive water jet (AWJ) is a progressive technology commonly used in many industrial applications. Potential of this technology is high and research in the field of optimal geometry design of an injection system has not been completed yet. New designs of the injection cutting head based on numerical simulation of the flow provide important information about processes occurring during the formation of AWJ. Detailed knowledge of velocities of abrasive particles during the abrasive water jet generation is vital for the verification of the numerical model. The aim of the experimental work was to test the applicability of the LIF (Laser Inducted Fluorescence) technique combined with the PTV (Particle Tracking Velocity) processing algorithms to analyze particle velocities at the output of the focusing tube. The combination of commonly used water pressures with abrasive mass flow rate was tested and the obtained results of abrasive particles velocities are presented in this paper.
Keywords:
abrasive particle velocity; LIF; PIV
Available in digital repository of the ASCR
Measurement and analysis of abrasive particles velocities in AWJ
Abrasive water jet (AWJ) is a progressive technology commonly used in many industrial applications. Potential of this technology is high and research in the field of optimal geometry design of an ...
Hardness and elasticity of abrasive particles measured by instrumented indentation
Hvizdoš, P.; Zeleňák, Michal; Hloch, Sergej
2015 - English
Basic mechanical properties of seven types (from seven different sites) of abrasive garnet particles used for water jet cutting were measured using the technique of instrumented indentation (also called depth sensing indentation or nanoindentation). Hardness and modulus of elasticity were evaluated and compared. All the abrasives had similar measured mechanical properties (hardness 20 – 24.16 GPa), the highest values were found for the Czech garnet.
Keywords:
abrasive; garnet; hardness; elasticity; instrumented indentation
Available in digital repository of the ASCR
Hardness and elasticity of abrasive particles measured by instrumented indentation
Basic mechanical properties of seven types (from seven different sites) of abrasive garnet particles used for water jet cutting were measured using the technique of instrumented indentation (also ...
CFD model of multiphase flow in the abrasive water jet tool
Říha, Zdeněk
2015 - English
The possibility of using CFD fluid flow modeling in area of tools with abrasive water jet is described in the paper. The correct function of such tool is based on proper setting of multiphase flow of water, air and solid particles in the inner space of the tool. The multiphase fluid flow numerical simulation can provide information which show relation between the geometry and the flow field. Then, this stable CFD model of multiphase flow creates key to design of the tool able to work with higher efficiency.
Keywords:
abrasive water jet; multiphase flow; CFD model
Available in digital repository of the ASCR
CFD model of multiphase flow in the abrasive water jet tool
The possibility of using CFD fluid flow modeling in area of tools with abrasive water jet is described in the paper. The correct function of such tool is based on proper setting of multiphase flow ...
An a posteriori error estimate for the Stokes-Brinkman problem in a polygonal domain
Burda, P.; Hasal, Martin
2015 - English
We derive a residual based a posteriori error estimate for the Stokes-Brinkman problem on a two-dimensional polygonal domain. We use Taylor-Hood triangular elements. The link to the possible information on the regularity of the problem is discussed.
Keywords:
a posteriori error estimate; Stokes-Brinkman problem; Taylor-Hood triangular elements
Fulltext is available at external website.
An a posteriori error estimate for the Stokes-Brinkman problem in a polygonal domain
We derive a residual based a posteriori error estimate for the Stokes-Brinkman problem on a two-dimensional polygonal domain. We use Taylor-Hood triangular elements. The link to the possible ...
Erosion effects evaluation of pulsating water jet on brass EN 12164
Lehocká, D.; Klich, Jiří; Foldyna, Josef; Hloch, Sergej; Cárach, J.
2015 - English
The objective of this experiment is to verify an assumption that with decreasing value of feed rate, mass v material removal Δ of brass EN 12164 during cutting by pulsating water jet is increased, and to seek the mass erosion curve course depending on the change of feed rate v [mm·s-1]. The selected observed parameter was evaluated in two units of Δ [mg·s-1] and Δ [mg·mm-1]. Two mutually related experiments were carried out. In the pilot experiment, the curve originating at hydraulic power output of 15 kW was evaluated that was achieved in combination of nozzle diameter d [mm] and pressure p [MPa] - d/p [mm/MPa] = 1.0668/52; 1.3208/39; 1.6002/31. After the pilot experiment, another experiment followed in which a particular range of feed rate values v = 0.2 - 8 mm·s-1 was selected. This resulted in finding that different courses of erosion process exist for mass material removal expressed in the form of curve Δ [mg·s-1] and Δ [mg·mm-1], depending on feed rate v [mm·s-1].
Keywords:
pulsating water jet; erosion; mass material removal; brass
Available in digital repository of the ASCR
Erosion effects evaluation of pulsating water jet on brass EN 12164
The objective of this experiment is to verify an assumption that with decreasing value of feed rate, mass v material removal Δ of brass EN 12164 during cutting by pulsating water jet is increased, ...
Study and characterization of natural bentonite modified by Manganese Oxides
Dolinská, S.; Schütz, T.; Znamenáčková, I.; Vaculíková, Lenka
2015 - English
The paper describes the preparation of new composite based on on relatively cheap natural materials from domestic deposits and synthetically prepared manganese oxides. The manganese oxides were precipitated on the surface of activated sodium bentonite particles.
Keywords:
bentonite; manganese oxide; domestic deposits
Available in a digital repository NRGL
Study and characterization of natural bentonite modified by Manganese Oxides
The paper describes the preparation of new composite based on on relatively cheap natural materials from domestic deposits and synthetically prepared manganese oxides. The manganese oxides were ...
GEOSITE AND GEOMORPHOSITE ASSESSMENT FOR GEOTOURISM PURPOSE: A CASE STUDY FROM THE VIZOVICKA VRCHOVINA HIGHLAND, EASTERN MORAVIA
Kirchner, Karel; Kubalíková, Lucie
2014 - English
Geotourism can be understood at a broader sense as geographical tourism sustaining environment, culture, aesthetics, heritage and the well-being of residents of a place or in a more restricted sense as a form of nature tourism that specifically focuses on landscape and geology. Geological, geomorphological and pedological sites are the most important resource for the geotourism activities. It is evident that not every site can be used for geotourism purposes. To find out which site can be used, it is necessary to identify, describe and assess various sites using a suitable assessment methodology. Based on the definition and conceptsof geotourism and the assessment methods already used for geomorphosite assessment, authors propose five groups of assessment criteria. The method was used for assessing selected sites in the Vizovickavrchovina Highland (Eastern Moravia, Outer Western Carpathians). Thanks to the assessment of the sites in this region, some potential geotourism resources were identified. Although the proposed method is numerical which should reduce the subjectivity, there is always a degree of subjectivity due to the fact that the real value of some criteria cannot be measured and it depends on assessor's experience, knowledge and preferences.
Keywords:
geodiversity; geoheritage; numerical assessment; Outer Western Carpathians
Available at various institutes of the ASCR
GEOSITE AND GEOMORPHOSITE ASSESSMENT FOR GEOTOURISM PURPOSE: A CASE STUDY FROM THE VIZOVICKA VRCHOVINA HIGHLAND, EASTERN MORAVIA
Geotourism can be understood at a broader sense as geographical tourism sustaining environment, culture, aesthetics, heritage and the well-being of residents of a place or in a more restricted sense ...
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