GPS (Global Positioning System) technique has become a major tool in contemporary surveying and geodesy. This concerns mostly measurements of horizontal point coordinates, where centimeter-level accuracies are usually required and easily achievable. For the height component, however, these requirements are higher and millimeter-level accuracy is necessary. On the other hand, the intrinsic precision of GPS-derived heights is clearly lower comparing to the horizontal components. This is due to unfavorable satellite geometry, adverse effects of the troposphere or GPS antenna phase center offset and variations. In order to overcome these effects one has to carefully model all the error sources and rigorously process the GPS data. This paper presents studies on the optimal GPS data processing strategy suitable for precise leveling. This was done through the extensive testing and selection of the most appropriate observational session duration, ambiguity resolution strategy, network geometry, troposphere and ionospheric delay reduction methods, signal linear co mbination, elevation angle cut-off, etc. The analyzed processing strategies were evaluated through the processing of a test network. The test network consisted of 19 monitored points and 5 control points, and covered the area of 20 km x 60 km. The obtained results show that the precise GPS leveling with the selected optimal processing strategy allows for about 3 mm repeatability of height measurements when processing 4-hour long sessions. In our opinion GPS leveling may serve as fast and cost-effective replacement of classic geometric leveling, especially in applications where the hei ghts in orthometric or normal height systems are not necessary. This is the case in, e.g., ground deformation studies., Katarzyna Stepniak, Radosław Baryła, Paweł Wielgosz and Grzegorz Kurpinski., and Obsahuje bibliografické odkazy
This paper deals with issues related to convenient monitoring of subsidence due to longtime mining activities of Czech Karviná Mine: Lazy plant, using satellite SAR interferometry (InSAR) techniques. It maintains approaches for optimizations of differential InSAR, especially including available filtering possibilities. It was realized that current SAR satellites were not able to appropriately evaluate deep subsidence as it occurs in Czech mining sites. Other issues are related to the presence of dense vegetation. Data from previous and only available L-band SAR satellite ALOS demonstrates its high potential in this area of interest. However, only a few acquisitions are available of the mining site disallowing usage for purposes of continuous monitoring of subsidence in the area. Processing results of InSAR techniques of the Lazy plant are presented in this paper., Milan Lazecký and Eva Jiránková., and Obsahuje bibliografii
Films of aliphatic polyurethane-silica nanocomposite containing up to 27.3 mol. % of silica were obtained by the parallel synthesis of both composite components in one common process. This method permits to obtain the nanocomposite materials with the uniform distribution of nanoparticles in the polymer matrix volume. The rise of the silica concentration in the nanocomposite film was shown to lead from one hand to the progressive fall of both the Young’s modulus and yield stress and from another hand to the rise of the ultimate deformation and thermal expansion coefficient values. These effects were ascribed to the formation of the excessive free volume in the material along with the raise of silica concentration., Josif V. Gofman and Ivan V. Abalov., and Obsahuje bibliografii
This study investigates the clay mineralogy of permafrost-affected soils derived from predominantly calcareous loess-like material under the cold ultra-continental climatic conditions of Central Yakutia. These soils are named "Palevye (Pale)" following the Russian Classification, or Cryosols (WRB, 2006). Based on the data obtained, the loess-like substrate of Central Yakutia is enriched by chlorite in comparison with that of the loess-like parent material of European Russia. The clay mineralogy of the fine size fractions (<1μm) of all soil profiles is dominated by a smectitic mineral (most likely random mixed-layer illite-smectite and probably chlorite-smectite where smectite is ≥ 50 %), with subordinate chlorite and illite as well as the products of their transformation with smectite (vermiculite) layers < 50 % in the upper horizons, and finally traces of kaolinite. Pedogenesis has brought about change in the more acidic upper horizons, including a marked reduction in the expandability of the smectitic phase, possibly accounted for by the introduction of non-exchangeable hydroxy-Al into the interlamellar space and / or partial dissolving of smectitic phase, together with a relative reduction in the contents of bothillite and chlorite. Illite has been at least partially transformed to a mixed-layer illite-vermiculite (smectite), whereas chlorite has either been completely decomposed or has transformed to a mixed-layer expandable component. In one profile, the smectitic mineral appears to be absent from the upper horizon, suggesting that it may have been completely decomposed. An alternative explanation is that it has been eluted or translocated down the profile to accumulate in a Bt horizon. The distribution of clay minerals relates to the change of pH values in the profiles (acidic in the upper part, neutral - slightly alkaline in the middle, and alkaline in the basal horizons) possibly determined by seasonal migration of dissolved carbonates., Sofia N. Lessovaia, Sergey V. Goryachkin, Roman V. Desyatkin and Matrena V. Okoneshnikova., and Obsahuje bibliografické odkazy
Two geodynamic test transects across the Polish segment of the Western Carpathians, crossing the Orava Basin in the west (KO) and the Pieniny Klippen Belt and Magura Nappe along the Dunajec River valley in the east (DD), are presented. Multidisciplinary studies conducted along these transects incl uded gravimetric, geodetic, geologic and morphostructural investigations. Gravimetric and geodetic results appear to suggest recent subsidence of the Orava Basin, particularly intensive in the Wróblówka Graben, confirming conclusions derived from geomorphic analyses. Data ob tained for the Dunajec River transect do not show any particular differentiation among individual benchmarks, what can point to either minor uplift of the entire area (already suggested by the results of geomorphic and morphotectonic studies), minimal differences between successive slices of the Magura Nappe and the Pieniny Klippe n Belt, or both. Horizontal displacements of benchmarks, different for the KO and DD transects, towa rds the west and SW as well east and SE, respectively, can result from general uplift of the area comprised between these transects, i.e. the Gorce Mts., Monika Łój, Janusz Madej, Sławomir Porzucek and Witold Zuchiewicz., and Obsahuje bibliografické odkazy
Geodynamic processes take place in the Carpathians even nowadays. For tracing them, a research project employing gravity measurements was undertaken. Movements in the crust result in a change of mass distribution, which may be traced with the use of a gravimetric method. Two measurement profiles were designed for tracing geodynamic changes, and in the years 2004-2005 gravimetric measurements were realised. The first results of observed gravity changes are presented in the paper and are followed by preliminary conclusions on the observed changes and the assumed measurement methods., Sławomir Porzucek, Janusz Madej and Monika Łój., and Obsahuje bibliografii
In Autumn 2010 a new permanent GPS station started observati ons intended to investigate the episodic displacements o f rocks in the Książ Massif, where the Geodynamic Laboratory (LG) is situated. These investigations are being made for common interpretation with water-tubes and horizontal pendulums tiltmeters registering large (one order of magnitude greate r than the tidal effects) non-periodic geodynamic signals. The studies conducted as up to date excluded instrumental and loading effects as potential reasons of those signals. The construction of water-tube tiltmeters and their measuring principles allowed to state that the strong non-tidal signals have a geodynamic nature. To support investig ation of this problem, different analysis of the GPS data are performed in appropriate scales and applying various processing methods. The applied methods refer to selected reference GPS stations in Poland and their neighbors and are aimed at reduction of disturbance effects of geophysical origin such as tectonic activity, post-glacial rebound, anthropogenic effects, etc., Ryszard Zdunek., and Obsahuje bibliografické odkazy
Physical mass properties of various types of rocks were ascertained, and their relationships are discu ssed in this article. Basedon water permeability and mercury intrusion porosimetry methods, conductivity coefficient, porosity, and pore size distribution were determined. Furthermore, bulk and particle densities of rocks we re determined. All laboratory tests were carried out according to Czech versi on of the Technical specif ication CEN ISO/TS 17892-11:2004. The above-mentioned specification has the status of the Czech standard (ČSN, CEN). Permeability and porosity are in close relation, and it could be assumed that its relationship is linear, i.e., with increasing porosity, permeability increases as well. This relationship is influenced by other rock properties, such as the amount of open and closed pores with in the rock sample, size, and distribution of pores or mineral admixtures. From this point of view, it is necessary to study these physical properties of rocks as well, because this enables an overall analysis of rocks and its possible use for engineering constructions, Jan Šperl and Jiřina Trčková., and Obsahuje bibliografické odkazy
Permeability refers to the ability of coal to transmit gas when a pressure or concentration gradient exists across it. The permeability of coal is dependent upon factors that include effective stress, gas pressure, water content, disturbance associated with drilling and matrix swelling/shrinkage due to adsorption/desorption. A programme of laboratory tests were conducted on coal samples from the Bulli seam for evaluating the permeability and drainability of coal. Two different types of permeability apparatus were used in this study. The methods of permeability testing of coal under different triaxial conditions are discussed. Permeability testing of the Bulli seam coal with N2 is described. The laboratory test results were found to be in agreement with the calculated permeability values, Naj Aziz, Ting Ren, Jan Nemcik and Lei Zhang., and Obsahuje bibliografii