Selected mechanical properties of unidirectional composites with polysiloxane-derived matrix and continuous basalt fibres reinforcement are presented. A special attention is devoted to the impact of long term exposition in hot air (aimed as a simulation of the anticipated operating conditions) to the composite failure under flexural load. The investigated composites worsened their properties after treatment in air at elevated temperature (650 - 750 °C). The originally non-catastrophic flexural failure changed to a brittle fracture, which was accompanied with a flexural strength decrease. The coalescence of fibres and their strong interaction with the matrix are probably the main reasons for the onset of brittleness. Unless these drawbacks are resolved the service temperature of the composites in air will probably not exceed approximately 500 °C., Petr Glogar, Martin Černý and Zdeněk Tolde., and Obsahuje bibliografii
The main assumption of this research was to check and verify the behaviour of a few EPN (European Permanent Network) stations on both sides of the Teisseyre-Tornquist zone (T-T zone), which is located on Polish territory and crosses Poland almost in half. The selected EPN stations’ time series were a subject of frequency and phase analysis. The main purpose of the research was to verify if there is any correspondence between stations located on one and on the other side of the T-T zone. The idea was also to check if any geological phenomena occurs on examined stations through the behaviour of the stations. The chosen period of research was between 2003 and 2008. The stations’ selection is not coincidental, VLNS, LAMA, BOGO, JOZE, BOR1 and WROC were chosen, because they had the longest and constant solutions provided by EPN. Using wavelets as a tool for analysis, the authors detected biases in time series on chosen EPN stations (near T-T zone). Applying multiresolution wavelet analyses on different stations in the component Up the frequency bands were achieved. The authors decided to analyze the low-frequency bias (wavelet approximation band). The reason of using this tool was to analyze the frequencies and also to compare the frequency phase, in order to have more complex analyses of physical phenomena of the T-T zone in Poland., Pawel Kaminski, Mariusz Figurski, Karolina Szafranek and Krzysztof Kroszczyński., and Obsahuje bibliografii
A Global Navigation Satellite System (GNSS) software library called G-Nut has been devel oped at the Geodetic Observatory Pecný (GOP) since 2011. Several applications built of the library will be provided as an open source in 2013 and consequently users are able to modify source code and use it for processing their own data free of charge. The main purpose of the project is to create a programming package suitable for implementing various end-user a pplications such as kinematic position estimation, long-term permanent station coordinates monitoring, zenith tropospheric delay estimation, satellite clock estimation and others. The library is written in C++ programming language following the object-oriented concept. Basic class structure implementing inputs/outputs and product/d ata containers support both real-time and post-processing modes. Integration of all available global navigation satellite systems (GPS, GLONASS, Galileo, BeiDou, QZSS) as well as new tracking signals is properly handled. The configuration is governed through the XML format. The estimation model currently supports the least square adjustment, the Kalman and square root covariance filtering methods based on processing undifferenced data and fixed precise orbit and clock products. The estimated state vector includes receiver coordinates and clocks, troposphere zenith path delays and initial carrier phase ambiguities. The first applications based on G-Nut library are shown with examples for off-line/online kinematic/static precise point positioning and ultra-fast troposphere estimation., Pavel Václavovic, Jan Douša and Gabriel Györi., and Obsahuje bibliografické odkazy
A new observation network has been built to observe the surface manifestations of undermining at Gabriela locality. This locality lies in the Czech part of the Upper Silesian Coal Basin and the history of the hard coal underground exploitation is more than 150 years long here. Recently, the last coal mining panel was started to be exploited here. Its location and mining parameters are very suitable for the analysis of the actual and future surface changes caused by undermining. The fixed points of the observation network are surveyed by geodetic GNSS me thod. This method enables the evaluation of both vertical subsidence and horizontal displacements. Such complex evalua tion of processes on the surface of the undermined territory makes it possible to understand the progress of the subsidence depression and to capture the final phase of the surface undermining changes, i.e. the phase of the subsidence decline., Vlastimil Kajzar, Hana Doležalová, Kamil Souček and Lubomír Staš., and Obsahuje bibliografické odkazy
A novel method called Generalized Average of Signals (GAS) for detection of very weak waves in seismograms is describe d and tested. The general principle of the GAS method is to take advantage of the cohe rency of the signal, which is extracted. The signals are shaped with moving window and converted to the frequency domain. Then they are non-linearly summed considering their complex representation (a mplitudes and phases). The method impr oves signal-to-noise ratio of coherent seismograms considerably. The GAS method is tested on sy nthetic seismograms and comp ared with the PWS method., Jiří Málek, Petr Kolínský, Jaroslav Štrunc and Jan Valenta., and Obsahuje bibliografické odkazy
The region of Central Europe, Adriatic region and Balkan Peninsula were subjects of geo-kine matical monitoring in several projects performed since 1992. Independent GPS epoch-wise observing campaigns took place in several regions and the whole territory is now covered by tens of permanent stations. The long-term observational series from permanent stations generally yield reliable site velocities, however distribution of such stations is not dense enough to provide velocity field with sufficient resolution all over the monitored region. On the other si de the epoch-wise campaigns sites are much denser than the permanent ones, however the repeated epoch observations are not very frequent and their referencing is not unique. In the paper we shortly describe velo city fields available from various national and regional GPS geo-kinematics projects and an attempt to homogenize the heterogeneous velocity fields is presented. The intraplate GPS velocities in Central and South-East Europe and their reliability are discussed, mainly focusing on Adria and East Balkan region where the geo-kinematics is mostly variable and complicated., Ján Hefty., and Obsahuje bibliografické odkazy
In the contribution the results of repeated precise levelling and GPS measurements at the central part of the Diendorf-Čebín tectonic zone (DCTZ) are presented. This morphologically very expressive tectonic system that belongs to a typical type of transcurrent tectonic system, with activity from Protherozoic up to recent period in separate parts is considered to be a seismoactive fault, too. Preliminary results at two measured profiles across central part of eastern marginal fault of the Boskovice Furrow confirmed expected vertical movement tendencies. It is evident that all tectonic system is seismoactive not only in the Lower Austria district but also in its northern continuation., Lubomil Pospíšil, Otakar Švábenský, Josef Weigel and Michal Witiska., and Obsahuje bibliografii
Rock block forms of the Szczeliniec Wielki (919 m a.s.l.) in the border area of the Stolowe Mountains massif originated due to various exogenous and endogenous pro cesses. The processes had started in the Upper Cretaceous, culminated in Late Tertiary, and continue till the present day with much lower intensity. Such processes were indica ted by historical earthquakes and different tectonic events in the Sudeten Mountains and adjacent areas. Results of geodetic geodynamic studies are presented. Several sectors of the Sudeten Mountains which include the Table Hills - Stolowe Mountains, show horizontal and vertical movements. Results of periodic precise levelling in three geodetic micro-networks established on the Szczeliniec Wielki: "Przy Schronisku", "Piekielko" and "Tarasy Poludniowe / Schody" are presented. Investigations have been augmented wit h TM-71 crack gauging in rock blocks. These studies started in 1972 increasing gradually effectiveness of monitoring. Levelling changes, as well as displaceme nts resulting from 3D monthly records of three TM-71 crack gauges have been confronted with recent investigations into tectonic micro-deformations along the Sudeten Fault in the Bohemian Massif. It is suggested that aseismic geotectonic processes participated in the deformations found in investigated networks., Stefan Cacoń, Blahoslav Košťák and Krzysztof Mąkolski., and Obsahuje bibliografické odkazy