Národní úložiště šedé literatury Nalezeno 47 záznamů.  začátekpředchozí38 - 47  přejít na záznam: Hledání trvalo 0.03 vteřin. 
Study of quality of nine aluminium alloys surfaces created using abrasive waterjet
Klichová, Dagmar ; Klich, Jiří ; Gurková, Lucie
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.
Study of surface topography of material eroded by pulsating water jet
Klich, Jiří ; Klichová, Dagmar
The paper focuses on the study of the effect of technological parameters on the topography of a surface eroded by a pulsating water jet. Parameters of the water pressure and the traversing velocity of the nozzle over the surface were observed. Effects of technological parameters were compared to the surface roughness parameters Ra, Rz, Rv, Rp, Rsk and Rku. The material tested was the aluminium alloy EN AW6060 T66. The surface was measured using an optical profilometer and further assessed using the confocal microscope based on a metallographic section.
Hardness and elasticity of abrasive particles measured by instrumented indentation
Hvizdoš, P. ; Zeleňák, Michal ; Hloch, Sergej
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.
Vodní paprsek 2015 - výzkum, vývoj, aplikace
Sitek, Libor ; Klichová, Dagmar
Čtvrté mezinárodní setkání výrobců, uživatelů, tvůrců a zájemců o technologii vysokorychlostního vodního paprsku. Fórum k výměně názorů, informací a zkušeností v oblastech výzkumu, vývoje a aplikací vysokorychlostních vodních paprsků (řezání, obrábění, sanace konstrukcí a staveb, čištění, odstraňování povlaků a nánosů, hydrodemolice, těžba, abrazivní materiály, speciální aplikace paprsku, vysokotlaká technika, bezpečnostní aspekty, atd.).
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.
Preliminary study using pulsating water jet for bone cement demolition
Hloch, Sergej ; Kloc, J. ; Foldyna, Josef ; Pude, F. ; Smolko, I. ; Zeleňák, Michal ; Sitek, Libor ; Hvizdoš, P. ; Monka, P. ; Monková, K. ; Kozak, D. ; Stoić, A. ; Sedmak, A. ; Milosevic, M. ; Lehocká, D. ; Mihalčinová, E.
The paper deals with the study of using the selective property of ultrasonic pulsating water jet for the disintegration of bone cement which creates the interface between femoral stem and trabecular bone tissue. For investigation, commercial bone cements were used. Bone cements were tested by nanoindentation in order to review their mechanical properties. A representative sample Palacos R+G was selected for disintegration of bone cement. Bone cements samples fixed between two plexiglasses were disintegrated using ultrasonic water jet and water jet generated by self-resonating nozzle at the pressure level of 20 MPa. Visualisation of bone cement demolition was provided with high speed 1 kHz cameras with two led pulsed sources. Potential were observed for using of pulsating water jet for bone cement demoliton during femoral stem extraction.
Effect of pulsating water jet peening on stainless steel
Hlaváček, Petr ; Kruml, T. ; Foldyna, Josef ; Tobiáš, J. ; Man, J.
Effects of action of pulsating water jet on polished surface of the stainless steel AISI 316L are presented. Surface slip bands appeared after this treatment. In the most severe conditions, microcracks were formed. Hardness measurement showed that the affected layer was thinner than 60 μm. Application of the pulsating water jet has beneficial effect on the fatigue life of the material.
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.
Concrete damaged by high temperature – possibilities of treatment with high speed water jet
Bodnárová, L. ; Válek, J. ; Sitek, Libor ; Foldyna, Josef ; Klich, Jiří
The paper describes analysis of behavior of cement based composite materials (concrete) exposed to high temperature. Recommendations for minimization of damage of thermally loaded structures are proposed and possibilities of renovation of fire damaged concrete using the technology of high speed water jet to remove damaged layers are given.
Hodnocení monitoringu napěťodeformačního stavu horninového masivu při dobývání sloje 30 (634) v rámci zkušebního provozu dobývací metody chodba-pilíř v OPJ Dolu ČSM - Sever
Waclawik, Petr ; Koníček, Petr ; Ptáček, Jiří ; Staš, Lubomír ; Kajzar, Vlastimil ; Kukutsch, Radovan ; Souček, Kamil
Jedná se o projekt monitoringu napěťodeformačního stavu horninového masivu při dobývání sleje č. 30 (634) v rámci zkušebního provozu nové metody chodba - pilíř v ochranném pilíři jam Dolu ČSM, lokalita Sever.

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