Number of results to display per page
Search Results
352. Sorption of alkylammonium cations on montmorillonite
- Creator:
- Navrátilová, Zuzana, Wojtowicz, Petr, Lenka Vaculíková, and Šugárková, Věra
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, adsorpce, montmorillonit, adsorption, montmorillonite, hexadecyltrimethylammonium, benzyldimethylhexadecylammonium, 7, and 551
- Language:
- English
- Description:
- Adsorption procedure of two cationic surfactants hexadecyltrimethylammonium bromide (HDTMABr) and benzyldimethylhexadecylammonium chloride (BDHDACl) onto two samples of montmorillonite was studied. Infrared spectroscopy and X-ray diffraction proved intercalation of both quaternary cations into the interlayer space of montmorillonite. An aspect of time showed not to be important for the cations adsorption., Zuzana Navrátilová, Petr Wojtowicz, Lenka Vaculíková and Věra Šugárková., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
353. Sorption of heavy metals on lignite impregnated with chitosan
- Creator:
- Havelcová, Martina, Jiří Mizera, Machovič, Vladimír, Borecká, Lenka, Oldřich Přibyl, and Krausová, Ivana
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, hnědé uhlí, chitosan, těžké kovy, sorpce, lignite, heavy metals, sorption, INAA, 7, and 551
- Language:
- English
- Description:
- A combined sorbent was prepared by impregnation of lignite mined in the South Moravian Coalfield, Czech Republic, with chitosan. Sorption performance of the combined sorbent and the untreated lignite was tested for Co(II), Cu(II), and Cd(II) in equilibrium sorption experiments with respect to pH and metal concentration. The amount of metal retained by the sorbent was determined by instrumental neutron activation analysis in the short time irradiation mode with epithermal neutrons. For pH~5, sorption isotherms were determined and fitted using the Langmuir and Freundlich models. The results have been compared with those obtained previously for similar combined sorbent based on naturally oxidized coal mined in the Sokolov Basin, Czech Republic. It has been shown that the effect of chitosan on sorption efficiency of the chitosan-doped coal sorbents strongly depends on solution pH, and type of coal and metal., Martina Havelcová, Jiří Mizera, Vladimír Machovič, Lenka Borecká, Oldřich Přibyl and Ivana Krausová., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
354. Stabilising rock surfaces with a glass reinforced polymer skin
- Creator:
- Nemcik, Jan, Baafi, Ernest, and Porter, Ian
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, skály, rocks, bolts and anchors, TSL support, laboratory testing, 7, and 551
- Language:
- English
- Description:
- Mine roadways developed in highly stressed strata are subject to roof shear, which under severe conditions may manifest as the well known symptom of guttering, particularly at the roadway edge leading into the major horizontal stress. This roof shear can progressively reduce the effectiveness of bolt confinement of the strata within the lower roof horizon affecting stability of the immediate roof. This paper presents the results of a study to investigate the effectiveness of polymers as skin reinforcement in highly stressed coal mine roadways, as they may provide better roadway skin support than the currently used steel mesh. A large concrete block intercepted with artificial joints and reinforced with steel bolts without skin support, was loaded until significant slip occurred along the joints. Upon loading, a roof cavity resembling a gutter developed, as some of the jointed concrete parted from the free surface. In addition to bolts, subsequent models with identical fracture planes were supported with steel mesh or with glass reinforced polymer skin bonded to the free side. Loads and displacements were compared for models with and without skin reinforcement. As expected the skin support helped resist gutter formation, to various degrees, while increasing the residual strength of the concrete block. It was found that there was significantly less bedding displacements in models with the polymer skin, when compared with both steel mesh and no skin reinforcement. This suggests that there would be benefits to using a spray on polymeric skin as surface support in roofs subject to severe roof shear., Jan Nemcik, Ernest Baafi and Ian Porter., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
355. Stability of period and quality factor of free core nutation
- Creator:
- Jan Vondrák and Cyril Ron
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, earth orientation, nutation, geophysical excitation, VLBI, 7, and 551
- Language:
- English
- Description:
- In our study we find, from the analysis of VLBI observations, small quasi-periodic fluctuations of the period and quality factor of retrograde Free Core Nutation (FCN), ranging mainly between 429.8 to 430.8 days and 17000 to 21000, respectively. To this end, we use resonant effects in several dominant forced nutation terms to calculate the period and quality factor of FCN in running 6-year intervals. We also recently demonstrated that the atmospheric and oceanic excitations are capable of exciting FCN. Both amplitude and phase of the geophysically excited motion are consistent with the values observed by VLBI, in the interval of tens of years. The geophysical excitations are now numerically integrated, using Brzeziński’s broadband Liouville equations, and removed from the observed celestial pole offsets. The remaining part is then used to derive the period and quality factor of FCN in running intervals, and to study the temporal stability of these important Earth parameters. It is demonstrated that the observed quasi-periodic variations of both parameters are probably not caused by these geophysical excitations., Jan Vondrák and Cyril Ron., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
356. Stanovení největšího odtoku přívalových dešťů pro úpravy toků
- Creator:
- Jan Horák
- Publisher:
- Jan Horák
- Format:
- print, text, regular print, and 15 s., 1 tab.
- Type:
- text, volume, studie, model:monograph, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, srážky dešťové, odtok povrchový, povodně, úprava vodních toků, hydrologie, 551.577/.578, 556.166, 7, 551, and UP05
- Language:
- Czech
- Description:
- napsal Dr. Jan Horák, Separát z: Technický obzor, 1912, and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
357. Station correction of patnet network for improvement of earthquake location in central part of Gulf of Corinth
- Creator:
- Jaromír Janský, Sokos, Efthimios, Serpetsidaki, Anna, and Lyon-Caen, Helene
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, zemětřesení, seizmicita, earthquake, seismicity, PATNET network, Aigion Greece 2001 earthquake sequence, CRLNET network, hypocentre relocation, 7, and 551
- Language:
- English
- Description:
- PATNET, the seismic network of the University of Patras, monitores regularly the seismic activity in the whole western Greece, using for a HYPO location a model, derived as an average representation for this broad area. One of the active regions of the western Greece is the Gulf of Corinth, which central part lies partially on the edge of the PATNET. Due to this and to the fact that the PATNET stations have mostly the vertical component only, the PATNET HYPO location of events in this region are often characterized by large standard errors in epicentres and especially in depths. Using a sequence of small earthquakes that occurred from February to May 2001 close to the city of Aigion, and was recorded by PATNET and as well by local Corinth rift laboratory (CRL) three-component network (CRLNET), we have derived for PATNET station and local model constants whose aplication improves the PATNET HYPO location of events in central part of Gulf of Corinth. These constants represent the main result useful for improvement of the future PATNET location in the given region., Jaromír Janský, Efthimios Sokos, Anna Serpetsidaki and Helene Lyon-Caen., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
358. Statistical evaluation of the 3D monitoring of displacements of dinaric fault zone in Postojna Cave, Slovenia
- Creator:
- Šebela, Stanka, Turk, Janez, Janez Mulec, and Stemberk, Josef
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, jeskyně, geodynamika, caves, geodynamics, Postojna (Slovinsko), Postojna (Slovenia), micro-tectonic displacements, 3D monitoring of displacements, TM 71 extensometer, statistical evaluation, Postojna Cave, Slovenia, 7, and 551
- Language:
- English
- Description:
- The results obtained by four years long TM 71 extensometer monitoring of 3D micro-tectonic displacements of Dinaric Fault Zone on two sites, being 260 m apart in Postojna Cave, were statistically evaluated with different methods (Kolmogorov- Smirnov test, comparison between relative displacement and earthquakes, linear regression, Kruskal-Wallis one-way analysis of variance, histograms and correlation coefficients). Responses to stress changes regarding x, y and z-axes are not the same on two monitoring sites even if we are monitoring the same fault zone. Kolmogorov-Smirnov test for comparing the two curves is applicable only for three axes combination (Postojna 1 z - Postojna 2 z, Postojna 2 y - Postojna 1 z, and Postojna 2 z - Postojna 2 y). Kruskal-Wallis analysis is most representative for z-axes. Some sharp peaks coincide with earthquake occurrences (Krn M=5.2, Cerkno M=4.0, Ilirska Bistrica M=3.9, Brežice M=2.9 and Krško M=3.1). Generally we detect very small tectonic deformations, dextral horizontal movement of 0.05 mm in 4 years for Postojna 1 and extension of 0.03 mm in 4 years for Postojna 2. Discrepancies between two sites can be attributed to complex geological structure and by the fact that studied fault zone is cut by cross-Dinaric fault zone., Stanka Šebela, Janez Turk, Janez Mulec, Blahoslav Košťák and Josef Stemberk., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
359. Stress and deformation states in underground structures using coupled modelling
- Creator:
- Petr Procházka and Jiřina Trčková
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, svahy, tunely, slopes (physical geography), tunnels, physical and numerical modelling, rock behaviour, inverse analysis, 7, and 551
- Language:
- English
- Description:
- The techniques of the method of the coupled modelling was substantially extended and used for solving problems connected with underground constructions for various materials and appropriate structural systems. In principle, a combination of linear effects of the external loading and material and time-dependent nonlinear change in structures was considered. Assessment of rock behaviour in surrounding of utility tunnels, solution of the structural strength below foundation, back analysis of reinforced soil slopes and studies of slopes endangered by groundwater were carried out., Petr Procházka and Jiřina Trčková., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
360. Structural analysis within the Rožná and Olší uranium deposits (Strážek Moldanubicum) for the estimation of deformation and stress conditions of underground gas storage
- Creator:
- Jiří Ptáček, Rostislav Melichar, Antonín Hájek, Petr Koníček, Kamil Souček, Staš, Lubomír, Kříž, Petr, and Lazárek, Josef
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, strukturní analýza, deformace, structural analysis, deformations (mechanics), stress, underground gas storage, 7, and 551
- Language:
- English
- Description:
- Uranium deposits, between which gas storage are being designed, the Rožná deposit and Olší deposit, are situated on the east edge of the Strážek Moldanubicum in Bohemian Masiff. Based on structural analysis it was possible to carry out the first rough prediction of potential weak zones in the rock mass. The structural analysis was also one of the supporting materials for determining the geometry and design method for the mine workings for the gas storage and for the advancing exploration of the gas storage region. Until now, the measurement of foliation planes and discontinuity planes in the survey crosscut V1-XXI and in a survey connecting gate GR1-XXI has been carried out. The results of interpretation of the measurement and monitoring of ductile elements (foliations) and joints (ruptures) as well as dislocations interpretation from the mine maps can be summarized and quoted in the contribution., Jiří Ptáček, Rostislav Melichar, Antonín Hájek, Petr Koníček, Kamil Souček, Lubomír Staš, Petr Kříž and Josef Lazárek., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public