| |
| |
| |
|
Hydro-abrasive machining of rotating workpieces from graphite and aluminium alloy
Cárach, J. ; Hloch, Sergej ; Klich, Jiří ; Hlaváček, Petr ; Klichová, Dagmar
The paper compares the quality of machined surface of graphite and aluminium alloy by abrasive water jet using the focusing tube with a diameter of df1 = 0.5 mm and df2 = 0.78 mm. The machining was carried out using the technology of rotating workpiece disintegration by abrasive water jet. Abrasive tangential water jet was used to carry out the experiment (water pressure p = 400 MPa). Workpieces were clamped in the rotating chucking appliance with rotation frequency n = 300 min-1. The change in focusing tube diameter caused the change in values of roughness parameters, and also caused the change of resulting shape of workpieces. Values of roughness parameters were measured using the MicroProf FRT optic profilometer.
|
|
The issue ensuring of foreigners
HLAVÁČEK, Petr
The bachelor thesis is dedicated to the detention of the foreign citizens according to the law dedicated to their residence in the territory of the Czech Republic. It is focused on defining what social background do these foreign citizens have and identifying the typical reasons leading to their detention. Part of the thesis is also dedicated to searching for the differences and weaknesses of the current institute of the detention of the foreign citizens in the Czech Republic, comparing this situation with the appropriate laws in the Slovak Republic and advising the appropriate changes in the law system.
|
| |
|
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
|
| |
|
Effects of pulsating water jet on materials with variously modified surface
Klich, Jiří ; Klichová, Dagmar ; Hlaváček, Petr
The paper deals with determination of erosion effects of pulsating water jet impinging the surface of aluminium alloy samples treated by various techniques (rough and fine milling, planing and rolling). The influence of the initial surface topography on the final topography of the sample exposed to pulsating water jet was investigated. Erosion of surface layer was analysed and discussed with respect to the traversing velocity of the jet. It was found, that properties of the initial surface have a significant impact on the final topography. Degree of erosion of the surface was determined by the measurement of surface parameter Ra.
Fulltext: content.csg - DOC Plný tet: UGN_0398577 - DOC
|
| |