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Start Over Subject Geologie. Meteorologie. Klimatologie Date Unknown

212. Humic acids quality of cambisols developed on gneiss and amphibolite

Creator:
Pospíšilová, Ľubica, Žigová, Anna, Šťastný, Martin, and Tibor Liptaj
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, rentgenová difraktometrie, huminové kyseliny, X-ray diffractometry, humic acids, cambisols, parent material, arable soil, grassland soil, SRATR FTIR and 13C NMR spectroscopy, 7, and 551
Language:
English
Description:
Chemical composition and structure of humic acids isolated from Cambisols forming on gneiss and amphibolite were studied. Cambisols differ in pH, cation exchange ca pacity, mineralogy composition, organic carbon input, plant residue and type of management. 13 C NMR and FTIR spectroscopy were used to show the main differences in humic substances quality. Humic acids isolated from soils developed on gneiss and amphibolite had wide variety of functional groups and different content of aromatic and aliphatic groups. Humic acids (HA) in arable soils contained more aromatic compounds and carbon in their molecule to compare with HA isolated from grassland. Forming of higher stability aggregates was connected with higher content of aliphatic groups in HA isolated from the grassland. Generally, humic acids in Cambisols represent young humic acids, with lower carbon content and high tendency to oxidation pr ocesses. Their chemical activity was mainly influenced by chemical composition and functional groups content., Ľubica Pospíšilová, Anna Žigová, Martin Šťastný and Tibor Liptaj., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

213. Hydrogen production by two-stage co-pyrolysis of bituminous coal-polymers mixtures

Creator:
Pavel Straka and Kříž, Vlastimil
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, uhlí, polymery, vodík, coal, polymers, hydrogen, co-pyrolysis, 7, and 551
Language:
English
Description:
The two stage co-pyrolysis method for obtaining of hydrogen is described. In the course of the heating of the mixture of bituminous coal with polyisoprene and styrene-butadiene polymers (co-pyrolysis), a considerable amount of hydrogen and hydrocarbons is released in dependence on the process conditions. The experiments proved that the amount of hydrogen increased already with slightly increased heating rate (5 K min-1 ) in comparison with the amount obtained at a common heating rate (3 K min-1) and, further, with the addition of the second (cracking) stage for further thermal splitting of release d hydrocarbons into hydrogen (and carbon), preferably at a temperature of 1200 ºC., Pavel Straka and Vlastimil Kříž., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

214. Hydrometeorologické srovnání povodní v srpnu 2002 s vybranými historickými případy dešťových povodní na Vltavě v Praze /

Creator:
Müller, Miloslav
Type:
text and studie
Subject:
Geologie. Meteorologie. Klimatologie, povodně, katastrofy přírodní, přehledná zpracování dějin českých zemí (chronologicky), and vědy o neživé přírodě, přírodní prostředí, astronomie
Language:
Czech
Description:
Hydrometeorogical comparison between the floods in August 2002 and selected historical rain floods on the Vltava river.
Rights:
unknown

216. Impact of Sumatra 2004 earthquake on geodynamic station GOPE (Czech Republic)

Creator:
Lukavec, Petr, Jan Kostelecký, Antonín Zeman, Jakub Kostelecký, Kouba, Jan, and Palinkáš, Vojtěch
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, GPS (navigační systém), GPS (navigation system), free oscillations, tidal gravimeter, PPP - Precise Point Positioning, spectral analysis, 7, and 551
Language:
English
Description:
The aim of this contribution is a detection of geodynamic effects at a very distant geodynamic station GOPE in the middle of Europe (Czech Republic). Strong earthquake, followed by strong indirect effect (tsunami), with the parameters (26.12.2004, 00:58:53.4 UTC, mag. 9.0, latitude 3.295N, longitude 95.982E, depth 30 km) was analysed from the records of tidal gravimeter (ASK No.228) with respect to free oscillations of the Earth (spheroidal component), by spectral analysis. This analysis detected significant vertical component of GOPE position in relatively long time interval (several hours) after the beginning of the earthquake. To verify the geodynamic tendencies of the GOPE station movements the GPS observations were analysed at the same time interval. We had data with 1s sampling interval at our disposal. For analysis we used PPP (Precise Point Positioning) method which produces absolute values of the coordinates in the ITRF 2000 system. Possible correlations between the results of both ways have been searched. We concentrated consequently to the determination of mean displacements and on the attempt of detection of some amplitudes of following free oscillations of the Earth. Mean change of position of the station GOPE during and after the earthquake, detected from the results of GPS observations is about 1.5 cm in horizontal and height components. Amplitude magnitudes for frequencies of the free oscillations of the Earth, which were analysed either from gravimetric data or from the GPS data, are equal in order. The study of free oscillations of the Earth by application of GPS is completely new. Studying of free oscillations is usualy accomplished by data from seismometers, tiltmeters or superconducting gravimeters., Petr Lukavec, Jan Kostelecký, Antonín Zeman, Jakub Kostelecký, Jan Kouba and Vojtěch Palinkáš., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

217. Impacts of hydrometeorological extremes in the Bohemian-Moravian Highlands in 1706-1889 as derived from taxation records /

Creator:
Dolák, Lukáš
Type:
text and studie
Subject:
Geologie. Meteorologie. Klimatologie, daně, prameny písemné, počasí, katastrofy přírodní, české země 1526-1792, české země 1792-1918, vědy o neživé přírodě, přírodní prostředí, astronomie, and finančnictví
Language:
English
Description:
Dopady hydrometeorologických extrémů na Českomoravské vrchovině v období 1706-1889 podle daňových záznamů.
Rights:
unknown

218. Implementation of the Vondrak's smoothing in the combination of results of different space geodesy techniques

Creator:
Štefka, Vojtěch and Ivan Pešek
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, geodezie, geodesy, Earth orientation parameters, combination of space geodesy techniques, Vondrak’s smoothing, 7, and 551
Language:
English
Description:
Four space geodesy techniques, namely VLBI, GPS, SLR and Doris, produce Earth orientation parameters (EOP) and station coordinates independently of each other. A method to combine them in a non-rigorous way (as described elsewhere) was modified by implementing Vondrak’s smoothing. It replaces a simple constraint to tie EOP at adjacent epochs by a more general expression defining smoothness of the resulting curves. This gives the method better stability of derived EOP. The new method was tested on GPS, VLBI and SLR data covering a one-year interval. The results were compared with the results of the original method and with the IERS c04 solution. The former indicates the effect of modification while the latter shows differences of this particular solution from the official IERS series, Vojtěch Štefka and Ivan Pešek., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

219. Influence of chemical and mineralogical composition of metakaolin on mortar characteristics

Creator:
Velosa, Ana Luisa, Rocha, Fernando, and Veiga, Rosário
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, metakaolin, mineralogie, malty, mineralogy, mortar, chemical composition, 7, and 551
Language:
English
Description:
Three different metakaolins processed by a Portuguese factory were studied aiming to assess the influence of chemical and mineralogical composition of metakaolin on mortar characteristics. Mineralogical analysis of both the fine and clay fractions was carried out by X-ray diffraction. Chemical composition (major elements) was analyzed by X-ray fluorescence. Mineralogical composition reveals some significant differences between the studied samples, in both analyzed fractions, metakaolin 2 being richer in kaolinitic minerals. From a chemical point of view, siliceous content is always high (aroun d 60 %) as well as Al2O3 content (around 30 %); once again metakaolin 2 is the one richer in Al2O3 and poorer in sodium and potassium. Metakaolin from the three different batches was incorporated in lime mortars in order to produce a pozzolanic reaction and hence enable them to harden in high relative humidity conditions or, when access to CO2 is limited, as in the case of mortars supporting glazed tiles. Mortars with the same volum etric ratio were tested for flexural and compressive strength at ages of 28 and 90 days, and the module of elasticity was dete rmined. A relation between the mechanical strength achieved by lime mortars with the addition of metakaolin from different batches and metakaolin mineral and chemical composition was assessed. The knowledge of the influence of the metakaolin com position on the strength of the mortars is an important step in improving their performance and extending their application., Ana Luisa Velosa, Fernando Rocha and Rosário Veiga., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

220. Influence of dislocations on bumps occurrence in deep mines

Creator:
Petr Procházka, Jiřina Trčková, and Lok, Tat Seng
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, numerické modelování, doly, numerical modeling, mines, free hexagon method, deep mines, bumps occurrence, 7, and 551
Language:
English
Description:
The problem of bumps occurrence in deep mines during the long wall mining appears to be one of the most serious one in the design of engineering of mining. The bumps are caused for various reasons, but basically it is an aftermath of the accumulated energy, which is released under some unfavorable conditions. In this paper the influence of given dislocations and their slope in a coal seam are studied based. The numerical tool is the free hexagon method. This method belongs to a set of discrete element methods and enables us to define and calculate stresses in a natural way along the interfacial boundaries of adjacent particles (elements). Since the bumps are affected by a possible slip along the dislocations, dynamical response has to be taken into account. The velocity of excavation of the mine is considered by successive change of values of Eshelby’s forces on the face of the wall., Petr Pavel Procházka, Jiřina Trčková and Tat Seng Lok., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public