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Experimental drying and desalination of bricks, sandstones and masonry under an applied electric field
Matyščák, Ondřej ; Katunský,, Dušan (referee) ; Ostrý, Milan (referee) ; Doc.Ing. Karel Kubečka, Ph.D (referee) ; Novotný, Miloslav (advisor)
Dewatering and desalination of building constructions is currently a discussed topic. At the present time, different techniques for dewatering and desalination can be used. The existing methods are efficient but it is necessary to improve these methods and to develop new ones. The moisture in the building constructions is directly connected with the salts, which can be dissolved in it and together with the moisture further to move. The salts can cause damage of constructions and change mechanical and physical properties of the buildings materials. The basic demands for dewatering and desalination are the speed, efficiency and economical factors. Presented dissertation focuses on dewatering and desalination with the use of electrokinetic methods together with the technique of the clay poultices. In the first part of the thesis, basic theoretical principles of moisture and salts are described. In the second part (experimental part), the series of experimental measurements were conducted both in the laboratory and in situ. In this part of dissertation, I was dewatering and desalinating bricks and sandstones under an applied electric field. The main focus was on the optimization of a laboratory setup in order to get the highest efficiency for dewatering and desalination. Other measurements were done in situ, where the same technique was used.
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Holocene Succession of Mollusc Assemblages in the Southern Part of Kokořínsko Area
Oravec, Jan ; Juřičková, Lucie (advisor) ; Beran, Luboš (referee)
The sandstone rock cities of the Bohemian Cretaceous Basin are traditionally considered floristically and faunistically impoverished areas, because the environment of acidic quartz sandstones complicates the development of developed biocenoses. The unfavourable abiotic conditions are compensated for geomorphological diversity of the landscape, which creates a wide range of locations providing habitats for many biological species with different ecological requirements. However, the current appearance of the sandstone areas is due to the extensive transformation of the environment in the late Holocene, as evidenced by the rich subfossil communities of terrestrial gastropods. In the presented study, the succession of postglacial malacocenoses was processed from five sites in the southern part of the Kokořínsko area, demonstrating the continuous development of species-rich forest habitats during the early and middle Holocene. The presence of calcareous encrustations on the surface of acidic sandstone walls, which allowed the continuous occurrence of calciphilous mollusc species, is also documented from this wet period. The gradual transformation of the natural environment is related to the beginning of the late Holocene and was caused by the leaching of nutrients from the soil horizons and the...
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Experimental drying and desalination of bricks, sandstones and masonry under an applied electric field
Matyščák, Ondřej ; Katunský,, Dušan (referee) ; Ostrý, Milan (referee) ; Doc.Ing. Karel Kubečka, Ph.D (referee) ; Novotný, Miloslav (advisor)
Dewatering and desalination of building constructions is currently a discussed topic. At the present time, different techniques for dewatering and desalination can be used. The existing methods are efficient but it is necessary to improve these methods and to develop new ones. The moisture in the building constructions is directly connected with the salts, which can be dissolved in it and together with the moisture further to move. The salts can cause damage of constructions and change mechanical and physical properties of the buildings materials. The basic demands for dewatering and desalination are the speed, efficiency and economical factors. Presented dissertation focuses on dewatering and desalination with the use of electrokinetic methods together with the technique of the clay poultices. In the first part of the thesis, basic theoretical principles of moisture and salts are described. In the second part (experimental part), the series of experimental measurements were conducted both in the laboratory and in situ. In this part of dissertation, I was dewatering and desalinating bricks and sandstones under an applied electric field. The main focus was on the optimization of a laboratory setup in order to get the highest efficiency for dewatering and desalination. Other measurements were done in situ, where the same technique was used.
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Sandstones and conglomerates Peruc Mbrs (lower Cenomanian , Upper Cretaceous ) of eastern Bohemia and coal mass in them
Martinec, Petr ; Kubina, Lukáš ; Rojáková, T.
A reasonably complete knowledge of the development of East Bohemia’s Lower Cenomanian sediments (Peruc Mbr) is still lacking. The sediments originate from rivers flowing from the buried Hořice-Nové Město elevation to Moravia in the SE direction, via a flatland depression. The sandstone and conglomerate bodies within the Litice Chlum area under investigation are channel river sediments accompanied by sedimentation in river lakes or oxbow lakes. The landscape of the region showed the character of a low-relief peneplain. At Sopotnice site, the surface of Litice kaolinite massif of granodiorite with a weathered crust incorporates fine-grained conglomerates with white quartz and quartzite pebbles in a sandy matrix. They form wedge-shaped channel bodies of several dozens centimeters thickness. The textures are massive, with inconspicuous positive gradation bedding of medium to poor bed sorting. By their character they correspond to the fill of an instable riverbed that kept changing its position in the flatlands. In the matrix, kaolinite dominates over illite.
Fulltext: content.csg -  DOC
Plný tet: UGN_0398209 - DOC
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Cave formation initiated by dissolution of carbonate cement in qartzose sandstones
Adamovič, Jiří ; Mikuláš, Radek ; Navrátil, Tomáš ; Mertlík, J.
Besides cavities of irregular shape, European sandstones also feature symmetrical cavities of spherical, ellipsoidal or teardrop shapes. Most of them are tens of centimetres across but some reach as much as 2–3 m in diameter and may coalesce into large caves tens of metres in length. Their origin has not been clearly explained yet. Based on the field comparison between such cavities in quartzose sandstones and incompletely developed cavities in carbonate-cemented sandstones, it can be demonstrated that the symmetrical cavities form by carbonate dissolution within the limits of former carbonate concretions. The diagnostic features of post-concretionary cavities include their circular or elliptical cross-section, a uniform orientation of their long axes across the region, and the presence of a set of parallel vertical joints or grooves/ribs on their inner walls. In some sandstone areas (e.g., Petite Suisse area in Luxembourg, Kokořín area in the Czech Republic), a wide variety of transitional forms can be found between the cavities and concretions forming positive relief on a vertical cliff face, depending on the position of the carbonate dissolution front in the present landscape.
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Phytogeographic importance of Central European sandstone regions
Härtel, Handrij
The importance of flora of the Central European sandstone landscapes is based not on the species richness (alpha diversity) but on the specific composition of flora. The flora of a sandstone region is characterized by a pronounced island environment resulting in frequent occurrence of relic species and isolated occurrences of many species. As a result of high habitat diversity, an unusual combination of various phytogeographic elements is specific to sandstone landscapes, such as atlantic/continental, boreomontane/thermophilous etc.
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Guide to the Post-conference excursion Sandstone Landscapes: Diversity, Ecology and Conservation
Mikuláš, Radek ; Adamovič, Jiří ; Cílek, Václav ; Hendrych, J. ; Líčenková, M. ; Mertlík, J. ; Mrkáček, Z. ; Petříček, V. ; Tomášek, O. ; Šoltysová, L. ; Vacková, D. ; Herben, Tomáš ; Kopřivová, L.
The Kokořínsko PLA, Bohemian Paradise PLA and Polická vrchovina Highland represent a high-diversity "sandstone phenomenon". Sandstones of the Bohemian Paradise can be considered as optimum for development of microrelief features influenced by saet erosion and case hardening.
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