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Printed circuit boards are part of electronic devices and affect the functioning of today's society. At present, printed circuit boards are manufactured for relatively long periods of time using the same methods. The presented article focuses on the design of the possibility which eliminates errors arising from the development and etching of PCBs. It describes the theoretical design of the use of hydrodynamic continuous water jet machining in PCB production. The proposal points to the possibility of using positive water jet properties are as such: no heat-affected zone, thin separation gap, absence of dust particles and toxic fumes.

The X-ray Computed Tomography (X-ray CT) represents a progressive non-destructive method of analysing the inner structure of materials. The method was used for monitoring changes in inner structure of concrete samples of different composition before and after their exposure to various thermal loads. Eight types of concrete samples were prepared which differed by cement and aggregate types. We intentionally used such composition of concrete mixtures which increased their resistance to high temperatures. The inner structure of samples was analysed using the micro X-ray CT before the thermal loading and after exposure of samples to temperatures of 600C and 900C respectively. Damages and character of changes in the inner structure caused by high temperatures were influenced by the character of cement and aggregate we used. The analysis of obtained results is presented in the paper. Rentgenová počítačová tomografie (CT RTG) představuje progresivní nedestruktivní metody analýzy vnitřní struktury materiálu. Tato metoda byla použita pro sledování změn ve vnitřní struktuře betonových vzorků různého složení před a po vystavení různým tepelným zatížením. Osm typů betonových vzorků byly připraveny, které se liší druhem cementu a typem kameniva. Byly záměrně použity takové složení betonových směsí, které zvýšily jejich odolnost vůči vysokým teplotám. Vnitřní struktura vzorků byla analyzována za použití mikro rentgenové CT před tepelným zatížením a po expozici vzorků na teploty 600 C a 900 C, resp. Škody a charakter změn ve vnitřní struktuře způsobené vysokými teplotami byly ovlivněny charakterem cementu a kamenivem jaké jsme použili. Analýza získaných výsledků je uveden v dokumentu.

Water Jet 2013 - Research, Development, Applications is the third international meeting of researchers, manufacturers, end-users, and all those interested in the technology of high-speed water jetting organized by the Department of material disintegration of the Institute of Geonics of the ASCR Ostrava. It provides a basis not only for exchange knowledge, ideas, information and experiences in areas of research, development and applications of water jets, as well as stimulating discussions, but also opportunity to make new acquaintances and friends. Number and diversity of papers submitted to the conference indicate permanent great interest in the water jetting technology and continuous expansion of water jets to new fields of human activities

U radu se ispituje analitički model moduliranih impulsa vodenog mlaza velike brzine s osnovnom frekvencijom za tehnologiju vodenog mlaza. Za to su bila potrebna laboratorijska mjerenja osnovne frekvencije oscilacija, njeno predviđanje i verifikacija. Hidrodinamički sustav generira modulirani vodeni mlaz kod određenog tlaka zbog rezonantne komore ugrađene u sustav. Teorijski model je naime razvijen na osnovi niza dimenzija i primijenjenog tlaka tekućine koji predstavljaju sustav. Postignuto je značajno poboljšanje kod dezintegracije površine obrađivanog materijala., The paper examines an analytical model of modulated pulses of a high-speed waterjet with a base frequency for waterjet technology. It required laboratory measurements of fundamental oscillations frequency, its prediction and verification. A hydrodynamic system generates a modulated liquid jet at a certain pressure due to a resonant chamber being integrated into the system. The theoretical model was developed particularly on the basis of a set of dimensions and the used liquid pressure which represent the system. A significant performance improvement was achieved in surface disintegration of material being machined.

The article deals with the application of new knowledge and trends in the generation of high-speed water jets and their utilisation during repair of concrete structures not only in laboratory conditions but also for practical use in-situ. Contribution examines several types of water jets with emphasis on reduction of economical intensity of the process of repair and treatment of rehabilitated surface for subsequent application of repair materials.