National Repository of Grey Literature 21 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Phenomenon of water in mining - gold panning, findings of ore mills in Slovakia.
Fajta, Martin ; Labuda, Jozef (advisor) ; Hrubý, Petr (referee)
Fajta, M. 2015: Phenomenon of water in mining - gold panning, findings of ore mills in Slovakia. [Master's thesis] Water has always been closely associated with the mining and processing of precious metals. Either it served as a secondary source from which gold was gained by gold-washing, or as a tool for further processing of primary mined ore. Thesis is divided into two sections which describe both of these options. In the first part, thesis deals with gold-panning. It describes sources for the history study of gold-panning in Slovakia and it presents current state of research. On the basis of historical knowledge from "De Re Metallica libri XII." (G. Agricola 1556) are presented the different types of chutes, which are used for gold-washing. This section also includes excursion about mining archaeology and excursion about origin and appearance of gold in Slovakia. The second part describes different steps in the processing of primary mined ores. Since there was no archaeological research of medieval facilities for processing ores in Slovakia, in the paper are presented examples of two researches of mining facilities from Czech Republic. In the chapters describing processing of ores is the biggest attention devoted to ore mills. The most common evidence for the existence of such mills are...
Methodic of pre-analytic sample selection
HRUBÝ, Petr ; MALÝ, Karel ; BÍŠKOVÁ, Jarmila ; GAŠPAR, Adam ; HAVLÍKOVÁ, Markéta ; HONS, David ; KAPUSTA, Jaroslav ; KMOŠEK, Matěj
This methodic offers approaches of pre-analytic selection of samples for, both financial and terminable realistic, analyses of samples from big collecions of archaeological and museal artefacts.
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Changes of slag particles during its alkaline activation
Pavlíčková, Ludmila ; Hrubý, Petr (referee) ; Bílek, Vlastimil (advisor)
This bachelor thesis deals with changes of slag particles during its alkaline activation. The altered parts of the slag as well as the course of the alkaline activation varies depending on the activator used, and therefore suspensions of blast furnace slag in sodium hydroxide, water glass, sodium carbonate and, for comparison, in water were prepared. Slag particles were isolated from these suspensions at selected time intervals (5 min, 30 min, 1 h, 2 h, 5 h and 24 h) for particle size analysis and evaluation of BET specific surface. After solidification, the microstructure of the samples was observed using an electron microscope. To better assess the reaction processes, the pore solution was isolated from the suspensions and its composition was analyzed using optical emission spectrometry in inductively coupled plasma. The hydration process was monitored using isothermal calorimetry.
Utilization of lignosulfonate plasticizer in alkali-activated materials
Zetocha, Martin ; Hrubý, Petr (referee) ; Kalina, Lukáš (advisor)
Tato bakalářská práce se zabývá využitím plastifikátorů na bázi lignosulfonátu v alkalicky aktivovaných materiálech. Sledován byl vliv na směs pasty aktivované vysokopecní strusky za použití hydroxidu sodného, vodního skla o různých modulech a uhličitanu sodného. Pozorován byl vliv plastifikátoru na bázi lignosulfonátu při zamíchávání do různých směsí, na zpracovatelnost, mechanické vlastnosti a reologii směsi. Důležitým faktorem byly použité aktivátory ve směsích. Nejlépe reagující směs na lignosulfonát se ukázala být za použití NaOH jako aktivátoru. Při pokusech pochopit reologické vlastnosti sledovaných směsí, jako klíčového faktoru chování těchto směsí bylo měření zeta potenciálu. Hodnoty zeta potenciálu nám daly bližší náhled na povrchový náboj častic vysokopecní strusky. Ten se prokázal jako klíčový faktor při posuzovaní účinnosti plastifikátoru. Tato zjištění budou vzata v úvahu a dále diskutovány v této práci.
Hybrid binders containing Portland clinker
Kratochvilová, Lucie ; Hrubý, Petr (referee) ; Opravil, Tomáš (advisor)
This bachelor thesis is focused on the use of cement kiln dust in combination with portland clinker. Cement kiln dust is a fine bulk material which is not good to mix further with cement, due to its unsuitable chemical composition. The aim of the bachelor thesis is to verify the possibilities of using this secondary material as a potential component of hybrid binders. For experimental part were taken several cement kiln dusts from different sources. The evaluation of the prepared binders was similar to Portland cement, the tests were performed according to ČSN EN 196.
Zjišťování početnosti prasete divokého v lesním prostředí
Hrubý, Petr
In the last time, there are growing problems with wild boar. Their overpopulation and problematic estimation of population density is a problem which is attached with another problems. The database of scientific papers dealing with the same topic was created. After that the suitable estimating methods was chosen for my future field works. In the locality of the Litovelské Pomoraví Protected Landscape Area, research was carried out to verify the estimation methods for wild boar (Sus scrofa) in forest environment. By the chosen method of direct observation was established the density of 128 individuals per 1000 hectares. The second chosen method was the method of the faecal pellet group counting within the striped transects. This method was modified and transects were situated on 21 experimental areas, which were equally distributed in the study area. By this method a density of 124 individuals / 1000 ha was determined. The results of the work show that it is advisable to use two independent counting methods to obtain an accurate estimate of the number of wild boar in the forest environment.
Zhodnocení prostorového chování a početnosti prasete divokého v lesním prostředí na základě analýzy distribuce trusu
Hrubý, Petr
The wild boar (Sus scrofa) is highly adaptable. This proves that it benefits in today's cultural and intensely exploited landscape. In the summer, it resides in fields where there is enough food, calm and causes damage to crop. During the winter period it moves to forests where conditions are less favourable. It is extensively hunted, disturbed by forest cuting, tourism and other human activities. In the winter time, it has only limited food sources in the woods, and therefore searches and visits the feeding sites. The escalating problems regarding the wild boar were an initiative to study his behavior. The behaviour was studied by analyzing the distribution of faecal pellet groups in the Bradlo forest complex with an area of 11.59 km2. The complex is situated in the northeast of the Czech Republic and is surrounded by agricultural landscapes. The distribution of faecal pellet groups was evaluated on 617 research areas (each covering an area of 100 m2), which were evenly distributed throughout the forest complex. In the first year (2017) was counted 20.4 individuals per km2. In the second year (2018) after intensive hunting during the year, 15.1 individuals were counted per km2. The research has examined the relationship between the amount of dropping and the factors such as geomorphological characteristics, distance from the feeding sites, water sources, forest edges, roads, hiking trails and intravilans. Impact of forest environment and Jurisdiction to the hunting area were investigated. It has been confirmed that most wild boar are staying in young dense forest stands, regardless of jurisdiction to hunting area, distance from roads, hiking trails, intravilans and areas with intensive forest cuting. With increasing distance from the edge of the forest, the number of droppings increased, and, conversely, with increasing distance from the feeding sites the number of droppings was smaller. The influence of geomorphological properties and distance from water courses has not been proved.
Effect of selected activators on the properties of alkali-activated composites reinforced with basalt fibers
Švardala, Daniel ; Hrubý, Petr (referee) ; Kalina, Lukáš (advisor)
This paper deals with the alkali activated materials (AAM) applicable as a construction material, thanks to low cost, environmental friendliness and good mechanical properties. The goal of this thesis is to search for suitable alkaline activator with respect to the final properties of alkali activated composite reinforced with basalt fibers. This thesis is focused on the determination the effect of basalt fibers addition on the mechanical properties. The influence of alkaline activator to basalt reinforcement was determined by simply strength tests, like the compressive and flexural strength measurements. The matrix fiber interaction, as one of the main parameters indicating the quality of the material reinforcement, was measured by electron scanning microscope equipped with an X ray energy dispersing analyzer (SEM EDS). It was found out that the most significant effect on the improvement of the mechanical properties of alkali activated material was in the case of the samples activated by sodium and lithium waterglass. The mechanical strength of these reinforced materials was considerably higher compared to non reinforced samples. AAM activated by potassium waterglass with and without the basalt reinforcement indicates the same or very similar mechanical strength. The comparison of composites with different alkaline activator leads to the conclusion that the mechanical properties depend on the type of used waterglass. AAM activated by sodium waterglass achieve the highest strengths compared to potassium and lithium waterglass activated materials and therefore seems to be the most appropriate for basalt fiber composites preparation.
Utilization of basalt fibers in alkali activated materials
Hrubý, Petr ; Šoukal, František (referee) ; Kalina, Lukáš (advisor)
Alkali activated materials (AAMs) represent construction materials with a huge potential especially because of environmental and economic aspects but sufficient mechanical properties as well. A fibre or fabric reinforcement of the AAMs could support more widespread application potential due to the mechanical properties, fracture toughness or composite durability improvement. Various alkaline activators were used for a blast furnace slag (BFS) activation to produce a suitable matrix for basalt fibres (BF) implementation in this thesis. The BFs represent applicable reinforcing material because of its favourable mechanical and thermal properties. Still, the utilization of BFs in the AAMs is quite limited due to the fibres low chemical stability under the alkaline conditions. Accelerated leaching tests with a determination of basalt fibres chemical composition same as tensile strength change using various analytical techniques (XRD, XPS, SEM-EDX, ICP-OES) have confirmed these assumptions. An influence of basalt fabric reinforcement in one or more layers on the mechanical properties was determined with the meaning of the compressive and flexural strengths. The fibre/matrix adhesion and transition zone properties were studied using SEM-EDX and pull-out tests as well because they are crucial parameters for the composite material reinforcement efficiency.

National Repository of Grey Literature : 21 records found   1 - 10nextend  jump to record:
See also: similar author names
13 HRUBÝ, Petr
2 Hrubý, Patrik
6 Hrubý, Pavel
13 Hrubý, Petr
2 Hrubý, Přemysl
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