The aim of this paper is to increase the stability of buildings and structures to natural disasters by modifying the Georgian clays into cement concrete filler by creation-using of rehydro-liming pozzolanization technology. The risk of damage-destruction of buildings and structures caused by earthquakes, sea storms, floods, mudflows, has increased in the world. Risks can be prevented by increasing of building and structure stability by reducing the anisotropy of cement concrete strength. To do this: Aqueous aluminosilicate minerals of clays, while dehydrating preserving habitus, are modified into a void containing (...mAl2O3∙nSiO2..) base minerals in which, after mixing in cement concrete while rehydro-liming, Ca(OH)2 is sorbed. The tobermorite, stratlingite, generated in filler, together with cement ettringite form fiber-needle-flaky habit clusters by modifying the structure of cement concrete with 3D self-nano-reinforcement, by reducing the anisotropy of strength - by increasing of stability to loads with variable direction-magnitude. It has been proven that in order to prevent risks of catastrophe, it is possible to use modification of Georgian clays by thermal dehydration in cement concrete technologies, which will create the preconditions for cement concrete pozzolanization by rehydro-liming, so the study of the basics of this process is actual., Rajden Skhvitaridze, Elena Shapakidze, IIoseb Gejadze, Merab Abazadze, Malxaz Turdzeladze, Teimuraz Cheishvili and Akaki Skhvitaridze., and Obsahuje bibliografii
Fluvial archives of the Polish Carpathians bear a record of both climatic and tectonic signatures. The former consist in cyclic development of terrace covers interfingering with and/or overlain by soliluction and slopewash sediments; the latter include disturbances within strath long profiles and differentiated size of erosional downcutting. Valleys of the Outer Carpathians bear five to nine terrace steps of Pleistocene age. Most of these terraces are strath or complex-response ones; the Weichselian and Holocene steps are usually cut-and-fill landforms, except those located in the neotectonically elevated structures characterized by the presence of young straths. Long profiles of individual strath terraces frequently show divergence, convergence, upwarping, downwarping, or faulting that can be indicative of young tectonic control. Moreover, the size and rate of dissection of straths of comparable age are different in different morphotectonic units; a feature pointing to variable pattern of Quaternary uplift. Rates of river downcutting result mainly from climatic changes throughout the glacialinterglacial cycles, but their spatial differentiation appears to be influenced by tectonic factors as well. Examples based on detailed examination of deformed straths and fluvial covers in selected segments of the Polish Carpathian rivers appear to indicate Quaternary reactivation of both normal and thrust bedrock faults. The latter are mostly confined to the eastern portion of the Outer Carpathians. The Early Pleistocene, Holsteinian and Eemian stages of reactivated faulting dominated throughout the study area., Witold Zuchiewicz., and Obsahuje bibliografii
Power generation from biomass is a substantial source of ashes, the extent of which depends on the type of biomass fuel and technology of combustion being used. The current study focuses on comparison of ashes with a special emphasis on hazardous organic compounds, particularly the polycyclic aromatic hydrocarbons (PAHs) fraction, present in ash. The reason is that ashes from combustion of wood or straw are considered as fertilizers in agricultural soils. Ash samples were therefore collected from power plants in the Czech Republic coming from combustion of wood chips, sawdust, bark and straw. The organic fraction was separated by extraction, the final determination of PAHs was performed by GC-UV. The total concentration of PAHs was found to be in the range 15-733 μ g/kg. These compounds are formed during the pyrolysis stage of the combustion process by the secondary ar omatization reactions in char at temperatures above 400 °C. The created PAHs are bound in the porous unburned carbon. For a more detailed qualitative analysis of other organic compounds the GC-MS was used. Higher and branched aliphatic hydrocarbons, ketones, amides and phthalates in the sample with the highest unburned carbon content were found., Pavel Straka and Martina Havelcová., and Obsahuje bibliografické odkazy
Different types of rock crusts and the underlying unweathered sandstone were sampled in the Bohemian Cretaceous Basin, Czech Republic. Structure and mineral composition of the samples were studied using optical microscopy, scanning electron microscopy with EDAX, and X-ray diffraction. Pore parameters were determined using mercury intrusion porosimetry/ helium pycnometry. Principal salts identified in the rock crusts and in the efflorescences are gypsum and alums. Two types of rock crusts were distinguished on morphological basis: 1. patterned rock crusts with a variety of weathering forms (honeycombs, wandkarren), and 2. armoured rock crusts with a relatively smooth, hardened layer. Patterned rock crusts on medium- to coarse-grained quartzose sandstones show an increase in the size of macropores relative to unweathered sandstone, which mostly implies an increase in total effective porosity. This is explained by the subflorescent growth of salt crystals, the force of which leads to the loss of contact among grains, pore widening, and granular disintegration. Armoured rock crusts on fine-grained clayey sandstone show a reduced volume and size of macropores, as these are filled with clay mineral aggregates and gypsum crystals. A prominent increase in the volume of micropores is due to secondary porosity in kaolinite and corrosion of feldspar grains. Insufficient passability of macropores in the armoured layer for pore waters shifts the evaporation front deeper into the rock. This results in contour scaling as the main process of rock-surface degradation, as opposed to granular disintegration on patterned rock crusts., Jiří Adamovič, Radek Mikuláš, Jana Schweigstillová and Vlasta Böhmová., and Obsahuje bibliografii
During separations in both polar and nonpolar stationary phases of gas chromatographic columns, side alkylchains of n-alkylphenols and n-alkylbenzenes become cyclized. In the aromatic-quasi-alicyclic molecules that are thereby formed, the effect of van der Waals forces is thus increased. The increase involves not only intramolecularly but also intermolecularly acting effects and becomes significantly evident when propyl and higher substituents as butyl, pentyl and hexyl constitute the side alkyl chains. As a result, boiling points considerably increase (non-linearly) in the case of n-alkylphenols and n-alkylbenzenes with total number of carbons in the molecule higher than 9. This leads to divergence in the retention characteristics of the above-mentioned compounds, which can be observed in the dependence of relative retention times on the number of carbons. Cyclization of side alkyl chains in a stationary phase is a quite new phenomenon., Pavel Straka, Petr Buryan and Jana Náhunková., and Obsahuje bibliografické odkazy
The Precise Point Positioning (PPP) analysis technique adapted for monitoring of moderate high-rate coordinate variations from GPS observations is applied for measuring actual displacements related to earthquakes. Two approaches are examined: kinematic PPP which is suitable for larger displacements and analysis of residuals from quasi-static PPP which is suitable for detection of minor displacements. Results from simulated horizontal movements of GPS antenna as well as analyses of 1 Hz GPS data from M 9.0 Sendai earthquake, M 6.3 L’Aquila earthquake and M 4.3 Tatabanya earthquake are shown. Our experiments proved the ability to measure dynamic seismic-related short-term coordinate variations at sub-centimetre level with PPP and to detect both strong and weak seismic signals using GPS satellites observations., Ján Hefty and Ľubomíra Gerhátová., and Obsahuje bibliografické odkazy
This paper presents the historical background of the 20th-century technology of geopolymers in light of a literature research of the 15th to 19th centuries and offers a hypothesis on why this historical knowledge was forgotten when Portland cement appeared. The recapitulation of the different cementitious calcareous matters returns all the way to the Bible builders; Ancient Vitruvius Pollio’s work "Ten Books of Architecture". These books were not only read but practically proven in pre-Portland times and especially at the beginning of 19th century. The long-term stability of Roman mortars and constructions was studied from the perspective of the cementitious materials, and the cited literature demonstrates the historical evolution of calcareous cements, then the reasons for the interruption of progress and return to the historical experience in the 1980s., Tomáš Hanzlíček, Ivana Perná, Zdenek Ertl and Sean M. Miller., and Obsahuje bibliografii
This paper provides a summary of the Geodetic Observatory Pecný achievements within the Centre for the Earth Dynamics Research (CEDR, 2005-2009) project in the field of precise near real-time GNSS analyses. The GOP data centre supporting our own near real-time activities as well as those of various other institutes has been enhanced by including GLONASS data, real-time GNSS data and some other supporting products. The ultra-rapid GNSS orbits are routinely determined and predicte dat GOP by analysing a global network of 60 stations. Significant improvements, which resulted in the fitted and predicted satellite positionrms of 4 and 10 cm, respectively, were achieved within the CEDR project. The GOP orbit product is updated every 6 hours and it routinely contributes to the International GNSS Service (IGS). Based on these predicted precise orbits, the GOP near real-time regiona l GNSS network solution is routinely provided for monitoring water vapour in the atmosphere. Resulting zenith troposphere delays achieved a standard deviation of 3-5 cm compared to precise EUREF post-processing results or a standard deviation of 1-2 mm when converted to precipitable water vapour and compared to a nearby radiosonde. The troposphere delays estimated in GOP are operationally used in the Numerical Weather Prediction., Jan Douša., and Obsahuje bibliografické odkazy