Number of found documents: 950
Published from to

Characterization of fine-grained montmorillonite fractions suitable for composite preparation
Valovičová, Věra; Vaculíková, Lenka; Plevová, Eva; Dolinská, S.; Znamenáčková, I.; Danková, Z.
2019 - English
The aim of this experimental study was to characterize a fine-grained fraction of montmorillonites (SAz-2, STx-1, SWy-2 and Kunipia-F). It was investigated in order to provide more precise information of used montmorillonites than could be obtained by analysis of the unfractioned montmorillonites. At first, the fine fraction of montmorillonites were prepared by sedimentation and activation by means of Na2CO3. The prepared clay materials were characterized by the X-ray diffraction analysis and FTIR spectroscopy. The thermal behaviour of the studied samples was determinated according to the characteristic temperatures obtained from TG/DTA curves. The temperatures of dehydratation and dehydroxylation were evaluated and kinetic parameters were also calculated. The porosity and surface properties of the studied samples were gained by the nitrogen adsorption measurements. The obtained results confirmed that the fine fraction of montmorillonites could be a suitable material for subsequent preparation of composites with enhanced sorption properties, especially montmorillonite/MnO2 composite. Keywords: montmorillonite; activation; characterization; composites Available in digital repository of the ASCR
Characterization of fine-grained montmorillonite fractions suitable for composite preparation

The aim of this experimental study was to characterize a fine-grained fraction of montmorillonites (SAz-2, STx-1, SWy-2 and Kunipia-F). It was investigated in order to provide more precise information ...

Valovičová, Věra; Vaculíková, Lenka; Plevová, Eva; Dolinská, S.; Znamenáčková, I.; Danková, Z.
Ústav geoniky, 2019

Zatížení svorníků v silně namáhavém masivu
Waclawik, Petr; Sahendra, Ram; Šňupárek, Richard
2019 - Czech
Při zkušebním provozu modifikované metody komora-pilíř s ponechanými stabilními pilíři, nazvané chodba-pilíř byla na Dole ČSM použita svorníková výztuž stropu a boků chodeb (stěn ponechaných pilířů). Zatížení a deformace svorníků byly měřeny v rámci rozsáhlého geotechnického monitoringu [1,2]. Následně bylo použito matematického modelování v softwaru Itasca FLAC3D [3] pro lepší objasnění zatěžovacích charakteristik svorníkové výztuže. The trial test of new mining method “Roadway-Pillar” was finished at the underground coal mine – ČSM Mine. The wide ranging monitoring was focused on the load bearing capacity of coal pillars and strata deformation changes induced by the roadway-pillar mining method. The results of monitoring allowed bolts loading and loading characteristics to be described. Further, an attempt is made to understand the rock bolt loading characteristics at different stages of rib dilation using numerical modelling with the available properties of rock mass and reinforcement for the studied site. Elastic and Mohr Coulomb strain-softening constitutive models are considered in FLAC3D to evaluate the performance of the rock bolts. Keywords: Roadway-Pillar mining method; ČSM Mine; coal pillars Available in a digital repository NRGL
Zatížení svorníků v silně namáhavém masivu

Při zkušebním provozu modifikované metody komora-pilíř s ponechanými stabilními pilíři, nazvané chodba-pilíř byla na Dole ČSM použita svorníková výztuž stropu a boků chodeb (stěn ponechaných pilířů). ...

Waclawik, Petr; Sahendra, Ram; Šňupárek, Richard
Ústav geoniky, 2019

Possibilities of using 3D laser scanning in geotechnical practise
Kukutsch, Radovan; Kajzar, Vlastimil; Šňupárek, Richard; Waclawik, Petr
2019 - English
We are experiencing the penetration of modern and smart technologies in all sectors of human activity, including mining and geotechnics. One of these technologies is 3D laser scanning, which has seen significant technological advancements over the last decade and has become an integral part of underground construction monitoring as a tool to enable comprehensive, accurate and unbiased capture of the spatial situation in digital form. This development was behind the fact that since 2013, 3D laser scanner has been used by the Institute of Geonics of the Czech Academy of Sciences as a necessary part of the geotechnical monitoring of mine works, when it is possible to precisely detect and quantify the time-space changes caused by man's intervention in the rock mass compared to the traditional established measuring methods. A leading project of recent years was the monitoring of the strain stress state of the rock massif during the 30th seam extraction during the trial operation of the Room and Pillar extraction method in the CSM Mine shaft safety pillar where, besides many other measuring instruments, 3D laser scanning was used for the convergence measuring of roadways, especially for capturing any deformation changes on the permanent pillars. A complementary function was the comparative evaluation with the results of other tools, e.g. with data measured by horizontal extensometers. The subject of the article will be a general description of the possibilities of using 3D laser scanning in geotechnical practice on spatial data acquired during the monitoring lasting almost 3.5 years, when important phenomena were detected in the movement of the pillar walls and the floor heave in the CSM Mine in the tens of cm, sometimes up to 100 cm. Keywords: 3D laser scanning; room and pillar; roadways deformation Available at various institutes of the ASCR
Possibilities of using 3D laser scanning in geotechnical practise

We are experiencing the penetration of modern and smart technologies in all sectors of human activity, including mining and geotechnics. One of these technologies is 3D laser scanning, which has seen ...

Kukutsch, Radovan; Kajzar, Vlastimil; Šňupárek, Richard; Waclawik, Petr
Ústav geoniky, 2019

Adsorption of pharmaceuticals from aqueous solutions onto clay minerals
Vallová, S.; Sokolová, B.; Valovičová, Věra; Plevová, Eva
2019 - English
The objective of this work was to investigate to possibility of clay minerals for the removal of drugs from aqueous solutions. Natural minerals such as montmorillonite, vermiculite, kaolinite and modified montmorillonites KSF and K10 (intercalated by Fe3+) were used as potential sorbents for three analgetics: paracetamol, ibuprofen and diclofenac from aqueous solutions. This research demonstrated that adsorption of all three pharmaceuticals onto natural untreated clay minerals, except paracetamol sorption on Na-MMT, is negligible. On the other hand, the chemically modified montmorillonites demonstrated significant sorption ability in the order diclofenac>ibuprofen>paracetamol. Keywords: adsorption; clay minerals; montmorillonite; paracetamol; ibuprofen; diclofenac Available at various institutes of the ASCR
Adsorption of pharmaceuticals from aqueous solutions onto clay minerals

The objective of this work was to investigate to possibility of clay minerals for the removal of drugs from aqueous solutions. Natural minerals such as montmorillonite, vermiculite, kaolinite and ...

Vallová, S.; Sokolová, B.; Valovičová, Věra; Plevová, Eva
Ústav geoniky, 2019

Malý pohled na historii suchých období v řece Punkvě se zřetelem na rok 2018
Lejska, S.; Kuda, František; Kněžínek, K.
2019 - Czech
Od roku 2012 lze pozorovat klesající trend hladiny vody podzemních krasových vod v povodí Punkvy. V roce 2018 klesl průtok na LG Skalní Mlýn na nejnižší hodnotu za posledních 60 let (75 l.s-1). To umožnilo suchý vstup do Dome jezera tvořící přítokovou jímku řeky Punkvy do Bludiště Milana Šlechty (Labyrint Milana Šlechty) v soutokové oblasti Sloupského potoka a potoka Bílé vody, v centrální části Amatérské jeskyně. Vana sousedí s Jezerní propastí (LAke Abyss) V té době nebylo prozkoumáno spojení mezi těmito dvěma lokalitami, takže naše pracovní skupina „Jezero Abyss - přítoková jímka řeky Punkvy“ prohledala tuto sekci pomocí 3D skeneru v srpnu 2018. Since 2012, one can observe a decreasing trend in the water level of underground karst water in the Punkva River basin. In 2018, the discharge at LG Skalní Mlýn dropped to the lowest value in the last 60 years (75 l.s-1). This permitted a dry entry to the Lake Dome forming the inflow sump of the Punkva River to Bludiště Milana Šlechty (Milan Šlechta Labyrinth) in the confluence area of the Sloup Creek and the Bílá voda Creek, in the central part of the Amatérská Cave. The sump is adjacent to the Jezerní propast (LAke Abyss) The connection between these two locations had not been surveyed at that time, so our work group „Lake Abyss – inflow sump of the Punkva River“ scanned this section using a 3D scanner in August 2018. Keywords: Punkva river; Amatérská cave; dry season Available at various institutes of the ASCR
Malý pohled na historii suchých období v řece Punkvě se zřetelem na rok 2018

Od roku 2012 lze pozorovat klesající trend hladiny vody podzemních krasových vod v povodí Punkvy. V roce 2018 klesl průtok na LG Skalní Mlýn na nejnižší hodnotu za posledních 60 let (75 l.s-1). To ...

Lejska, S.; Kuda, František; Kněžínek, K.
Ústav geoniky, 2019

Cultural functions and services of geodiversity within urban areas (with a special regard on tourism and recreation)
Kubalíková, Lucie; Bajer, A.; Drápela, E.; Zapletalová, D.; Kirchner, Karel; Balková, M.; Zágoršek, K.; Kuda, František; Roštínský, Pavel
2019 - English
Geodiversity (or abiotic nature) within urban areas has numerous functions and offers various benefits and services. In addition, it has strong links to cultural heritage and historical aspects and it influences and is influenced by urban development and planning. The geodiversity functions and services can be sorted according to the ecosystem services approach: regulating, supporting, provisioning and cultural services. The last mentioned includes a wide spectrum of aspects (spiritual, religious, historical, archaeological, social, artistic, sense of place etc.) and besides this, it encompasses also the tourist and recreational functions which are (in some cases) unexplored and underestimated in urban areas. The paper presents examples from two different Czech cities – Brno and Liberec. Selected geocultural sites are described and assessed and specific proposals for tourist, recreational and educational use are outlined. The results of evaluation show that they can represent an interesting alternative to the traditional tourist destinations within urban areas. Keywords: geotourism; geocultural site; assessment; Brno; Liberec Available in digital repository of the ASCR
Cultural functions and services of geodiversity within urban areas (with a special regard on tourism and recreation)

Geodiversity (or abiotic nature) within urban areas has numerous functions and offers various benefits and services. In addition, it has strong links to cultural heritage and historical aspects and it ...

Kubalíková, Lucie; Bajer, A.; Drápela, E.; Zapletalová, D.; Kirchner, Karel; Balková, M.; Zágoršek, K.; Kuda, František; Roštínský, Pavel
Ústav geoniky, 2019

EFFECTS OF ABRASIVES DURING ACCELERATED\nSIMULATION OF MECHANICAL CORROSION OF CEMENT COMPOSITES USING ABRASIVE WATER FLOW
Hlaváček, Petr; Sitek, Libor; Klichová, Dagmar; Bodnárová, L.
2019 - English
The paper deals with the use of the abrasive water flow technology in an accelerated simulation of the process of mechanical degradation of surface layers of cement-based composites by flowing liquids. Effects of the abrasive particle size and the mass flow rate of abrasives in an abrasive water flow impacting on the surface of concrete samples have been studied. In addition, suitability of the application of the abrasive water flow for the simulation of real situation of the surface wear by flowing liquids has been evaluated. Keywords: cement-based composite; erosion; abrasion; cavitation; high-speed water flow; abrasive material Available on request at various institutes of the ASCR
EFFECTS OF ABRASIVES DURING ACCELERATED\nSIMULATION OF MECHANICAL CORROSION OF CEMENT COMPOSITES USING ABRASIVE WATER FLOW

The paper deals with the use of the abrasive water flow technology in an accelerated simulation of the process of mechanical degradation of surface layers of cement-based composites by flowing ...

Hlaváček, Petr; Sitek, Libor; Klichová, Dagmar; Bodnárová, L.
Ústav geoniky, 2019

Application of bentonite-manganese oxide composites in removal of heavy metals
Dolinská, S.; Znamenáčková, I.; Tomčová, J.; Valovičová, Věra; Vaculíková, Lenka; Plevová, Eva
2019 - English
The paper is aimed on the using of non-homogeneous bentonites coated by manganese oxides for the removal of heavy metal cations from the water solutions. In the first stage Slovak natural bentonite was converted to sodium form using by Na2CO3 as the activating agent. After that the manganese oxides were precipitated on the surface of natural and sodium activated bentonite, respectively. The structural changes before and after the modifications of bentonites were characterized by X-ray diffraction analyses and X-ray photoelectron spectroscopy. To compare the sorption properties of the natural bentonite and modified bentonites, sorption experiments of Cd2+ from aqueous solutions were done. Keywords: bentonite; composites; adsorption Available in digital repository of the ASCR
Application of bentonite-manganese oxide composites in removal of heavy metals

The paper is aimed on the using of non-homogeneous bentonites coated by manganese oxides for the removal of heavy metal cations from the water solutions. In the first stage Slovak natural bentonite ...

Dolinská, S.; Znamenáčková, I.; Tomčová, J.; Valovičová, Věra; Vaculíková, Lenka; Plevová, Eva
Ústav geoniky, 2019

Thermal behaviour of organically modified smectites
Plevová, Eva; Vaculíková, Lenka; Valovičová, Věra; Simha Martynková, G.
2019 - English
The smectites were modified with different types of alkylammonium cations. The X-ray powder diffraction was used to calculate the values of the basal space of the modified smectites to confirm the intercalation of cations into the structure. The montmorillonites were also characterized by means of FTIR spectroscopy, which proved sorption or intercalation of the alkylammonium cations too. Thermal behaviour of the smectites was investigated by simultaneous thermogravimetry and differential thermal analysis. The temperatures of dehydratation and dehydroxylation and the temperatures related to total melting and recrystallization generally changed. Study of temperatures changes together with determination of kinetic parameters helped to obtained a comprehensive assessment of smectite thermal stability. Keywords: smectites; intercalation; thermal analysis Available in digital repository of the ASCR
Thermal behaviour of organically modified smectites

The smectites were modified with different types of alkylammonium cations. The X-ray powder diffraction was used to calculate the values of the basal space of the modified smectites to confirm the ...

Plevová, Eva; Vaculíková, Lenka; Valovičová, Věra; Simha Martynková, G.
Ústav geoniky, 2019

Možnosti využití 3D laserového skenování v geotechnické praxi
Kukutsch, Radovan; Kajzar, Vlastimil; Šňupárek, Richard; Waclawik, Petr
2019 - Czech
S pronikáním moderních a smart technologií se setkáváme ve všech odvětvích lidské činnosti, oblast hornictví a geotechniky nevyjímaje. Jednou z těchto technologií je i 3D laserové skenování, které za posledních deset let zaznamenalo výrazný technologický pokrok a stalo se nedílnou součástí monitoringu podzemních staveb jako nástroj umožňující komplexní, přesné a nezkreslené zachycení prostorové situace do digitální podoby. Právě tato skutečnost stála za tím, že je od r. 2013 3D laserový skener využíván pracovníky Ústavu geoniky AV ČR, v.v.i. jako nezbytná součást geotechnického a geotechnického monitoringu důlních děl, kdy lze oproti tradičním, zavedeným měřičským metodám, velmi přesně detekovat a kvantifikovat časoprostorové změny vyvolané zásahem člověka do horninového masivu. Nosným projektem posledních let byl monitoring napěťodeformačního stavu horninového masivu při dobývání 30. sloje v rámci zkušebního provozu dobývací metody Room and Pillar (chodba-pilíř) v ochranném pilíři jam Dolu ČSM, kde vedle mnoha jiných měřicích instrumentů bylo 3D laserové skenování využíváno pro konvergenční měření chodeb, zejména ale pro zachycení veškerých deformačních změn na ponechaných pilířích. Doplňkovou funkcí bylo komparativní hodnocení s výsledky jiných nástrojů, kupř. s údaji naměřenými pomocí horizontálních extenzometrů. Předmětem příspěvku tak bude všeobecné vytyčení možností uplatnění 3D laserového skenování v geotechnické praxi, a to na prostorových datech pořízených během monitoringu trvajícím bezmála 3,5 roku, kdy byly na Dole ČSM zachyceny významné fenomény v pohybu stěn pilíře a vyzvedávání počvy v řádu desítek cm, místy až 100 cm. We are experiencing the penetration of modern and smart technologies in all sectors of human activity, including mining and geotechnics. One of these technologies is 3D laser scanning, which has seen significant technological advancements over the last decade and has become an integral part of underground construction monitoring as a tool to enable comprehensive, accurate and unbiased capture of the spatial situation in digital form. This development was behind the fact that since 2013, 3D laser scanner has been used by the Institute of Geonics of the Czech Academy of Sciences as a necessary part of the geotechnical monitoring of mine works, when it is possible to precisely detect and quantify the time-space changes caused by man's intervention in the rock mass compared to the traditional established measuring methods. A leading project of recent years was the monitoring of the strain stress state of the rock massif during the 30th seam extraction during the trial operation of the Room and Pillar extraction method in the CSM Mine shaft safety pillar where, besides many other measuring instruments, 3D laser scanning was used for the convergence measuring of roadways, especially for capturing any deformation changes on the permanent pillars. A complementary function was the comparative evaluation with the results of other tools, e.g. with data measured by horizontal extensometers. The subject of the article will be a general description of the possibilities of using 3D laser scanning in geotechnical practice on spatial data acquired during the monitoring lasting almost 3.5 years, when important phenomena were detected in the movement of the pillar walls and the floor heave in the CSM Mine in the tens of cm, sometimes up to 100 cm. Keywords: 3D laser scanning; room and pillar; roadways deformation Available at various institutes of the ASCR
Možnosti využití 3D laserového skenování v geotechnické praxi

S pronikáním moderních a smart technologií se setkáváme ve všech odvětvích lidské činnosti, oblast hornictví a geotechniky nevyjímaje. Jednou z těchto technologií je i 3D laserové skenování, které za ...

Kukutsch, Radovan; Kajzar, Vlastimil; Šňupárek, Richard; Waclawik, Petr
Ústav geoniky, 2019

About project

NRGL provides central access to information on grey literature produced in the Czech Republic in the fields of science, research and education. You can find more information about grey literature and NRGL at service web

Send your suggestions and comments to nusl@techlib.cz

Provider

http://www.techlib.cz

Facebook

Other bases