Local seismicity of the Hronov-Poříčí Fault Zone is studied using two-year continuous seismic data from four seismic stations in the area. Newly developed software for automatic seismic events detection is introduced - it is based on the method used at the Icelandic seismic network. Twelve major local earthquakes are detected, localized and their magnitudes are estimated. Simultaneously, groundwater levels are continuously monitored in three wells in the area. Multiple-filtering method, originally used for processing of broadband and dispersed seismic signals, is modified and used for the frequency-time analysis of the water level data. Dominant tidal influence on the groundwater level variations is shown. Theoretical tidal potential for all three well locations is computed. Groundwater data and tidal potential are bandpass filtered to focus on the semidiurnal periods. Mutual amplitude ratio and phase shift between both quantities are computed. Each of the three wells exhibits different pattern of the groundwater level variations with respect to tides. A distinct change in the phase shift is observed at the VS-3 well in the second half of 2009. In the same time span, increased seismic activity is also observed. However, other two wells do not exhibit any evidence of such phase shift. Detailed groundwater level data analysis does not prove any significant rises or drops of the groundwater levels in 28 day intervals around the detected local events. In contras t, unexplained groundwater level drop in the V-34 well is obser ved 18 hours before the teleseismic Tohoku earthquake, Japan, March 11, 2011, Mw = 9.0., Petr Kolínský, Jan Valenta and Renata Gaždová., and Obsahuje bibliografické odkazy
Bosnia’s seismotectonics seems to follow the Mediterranean marine regime. Earthquakes occur mostly in the outer Dinaric Alps (southern Bosnia), while the strongest earthquakes occur within the Sarajevo Fault system in southern and northwestern Bosnia. In addition to active tectonics being strong, crustal earthquakes occur often as well. Due to Bosnia’s rich hydrogeology, crustal loading such as by snow and rain, or reservoir inundation, represents the most important secondary seismogenic source in the region. Despite its exquisite and active geomorphology no comprehensive and reliable geodynamical studies exist on the region. Seismic sensors coverage is extremely poor also. One centenary analogue, and a few recently installed digital seismometers are insufficient for a region that exhibits mild-to-high seismic activity. Significant investments are needed in order for GPS, seismic and other sensor-instrumented networks to be put in place or enhanced. Technical personnel needs to be educated to enable support provide for studies that are done within broader scientific activities. Such efforts that presently seek to include Bosnia under their scope are ESF-COST Action 625, NATO Stability Pact DPPI program, and EUREF/CERGOP geophysics projects., Mensur Omerbashich and Galiba Sijarić., and Obsahuje bibliografii
A detailed geomorphological mapping was performed in the valley of the Losenice R., which is situated on the NE slopes of the Šumava Mts. nearby the Kašperské Hory town. The dominant characteristics of the studied area are steep slopes of the deeply incised, narrow valleys, strong fragmentation of the bedrock composed of various types of gneisses and obvious structural influence on the valley network plan. Based on the analysis of the occurrence, parameters and relative position of selected landforms, which have significance for documenting certain processes, as well as other inputs, the relief of the studied area was divided into eight genetic types of relief segments: structural, erosional, erosional-structural, structuraldenudational and erosional-denudational slopes, flat denudational ridges and planation surface remnants and finally the valley floors with the floodplain., Filip Hartvich and Vít Vilímek., and Obsahuje bibliografii
Since 1998, a seismic network has been monitoring the underground gas storage located near the town of Příbram in the Central Bohemian Pluton, Czech Republic. Hundreds of weak induced seismic events have been recorded there. Moreover, several weak earthquakes have also been recorded from the vicinity of the nearby Orlík water reservoir. To improve location of both types of seismic events, shallow crustal structure of the region is studied in the present paper. Refraction measurements to distances of about 20 km were carried out using quarry blasts as seismic sources. Smoothed P-wave travel times were interpreted using the Wiechert-Herglotz method, which yielded a 1-D velocity model of shallow crustal structure down to a depth of about 1.7 km. The P-wave velocity of the model increases from about 5.0 km/s at the surface to about 6.15 km/s at the 1.7 km depth., Jiří Málek, Oldřich Novotný and Libor Žanda., and Obsahuje bibliografii
In this study shape optimization of fibers in composite fiber reinforced structure is presented. The problem targets the optimal shape with respect to the maximum bearing capacity and the minimum deformation of the whole composite set up. The shape is constrained by a constant volume (area) ratio. The optimization includes a process of seeking the overall properties of composites, i.e. localization and homogenization. Since no a priori estimate of the shape of fibers is known, numerical tool, finite element method, is employed. Such a problem is important in a wide range of applications, prevailingly in fiber reinforced concrete assessment, biomechanics, biophysics, and in the mechanics of classical composites with epoxy matrix. Since many types of fibers are used in various fiber reinforced concretes (fibers from polypropylene, steel, glass, clay, basalt, hemp, etc.), a deeper study is of importance to engineers and researchers. Application on FRC is preferred, i.e. fiber volume ratio is small, while classical composites require relatively very high volume ratio. The theory involves an original procedure leading to the optimal shape of fibers; it is then applied in the form of a numerical study. Also two examples from experiments verify the theoretical results. The problems are solved as two-dimensional, i.e. a unidirectional distribution of fibers is supposed., Petr P. Procházka and Martin Válek., and Obsahuje bibliografii
Rayleigh waves in the period range 0.2 - 3.0 s from eight quarry blasts are analyzed to obtain S-wave velocity model beneath the Příbram seven-station array in the Czech Republic. Locations and origin times of blasts are estimated using P- and S-wave onsets and then verified at the quarry in the vicinity of the location. This blind test confirms a sufficient precision of the location procedure for identification of quarries. Epicentral distances are in the range from 16 to 52 km. Group velocity dispersion curves of Rayleigh waves are determined by the frequency-time analysis. An average group velocity beneath the array for each period is computed with the help of mean travel-time curve for all blasts and stations. The resultant group velocity dispersion curve is inverted to obtain a 1-D S-wave velocity model using the Isometric method. The results are compared with known geological structure in the area of interest., Renata Gaždová, Petr Kolínský, Jiří Málek and Jan Vilhelm., and Obsahuje bibliografii
Vermiculite (V) from Brazil with aqueous solutions AgNO3 and/or Cu(NO3)2 was used for preparation of nanocomposites V/Ag, V/Cu, V/AgCu and V/CuAg using two procedures and their effect on bacteria was compared. Structural changes were evaluated using X-ray diffraction (XRD) analysis, Infrared spectroscopy (IRS) and Scanning electron microscopy (SEM). Elemental chemical composition was determined using X-ray fluorescence (XRF) analysis and the solutions were analyzed by Atomic emission spectroscopy with inductively coupled plasma (AES-ICP). Antibacterial properties of Ag- and Cu-vermiculites and combined Ag/Cu-vermiculites were tested on two bacteria groups: (1) Gram-positive, G+, (Staphylococcus aureus and Enterococcus faecalis) and (2) Gram-negative, G-, (Pseudomonas aeruginosa and Klebsiella pneumoniae). The samples under antibacterial testing showed different effective times and minimum inhibitory concentration (MIC) values. The Gram-negative bacteria showed higher sensitivity to the prepared samples than Gram-positive bacteria. The combined Cu/Ag vermiculites stopped the bacterial growth at lower MIC value., Marianna Hundáková, Marta Valášková, Vladimír Tomášek, Erich Pazdziora and Kateřina Matějová., and Obsahuje bibliografii
Oxidation kinetics of celulose, lignin, brown coal, and their mixtures were investigated. Using non-linear regression method kinetic parameters from thermogravimetric curves were calculated for oxidation of volatile matter and fixed carbon (char). The presence of the cellulose in the mixture affects the rate constant of lignin and brown coal oxidation which was determined by means of Arrhenius plots., Petr Šušák, Silvie Vallová and Juraj Leško., and Obsahuje bibliografii
Series of repeated epoch-wise GPS campaigns performed in Central European region are used for estimation of site velocities. The main features of campaign processing and combination of network solutions are outlined. The velocities obtained from epoch observations within the Central Europe Regional Geodynamic Project covering the 11-year time span are compared at some sites with velocities derived from permenent GPS observations., Ján Hefty and Ľubomíra Gerhátová., and Obsahuje bibliografii
Stability conditions in a wider surrounding of the rock castle Drábské Světničky (Drábské Rooms) near the town of Mnichovo Hradiště were investigated. The area which has been intensively disturbed by large old as well as present slope movements is located in the north-western part of Příhrazy Platform. Solid, thick bedded sandstones, well resistant to weathering, are lying on claystones apt to plastic deformations. Marginal sandstone blocks separate, move down on the slope and sink into the plastic bedrock. As a result, block fields with many crevasses develop. In rock walls that separate individual blocks, rockfalls originate and central, as well as lower parts of the slopes develop large landslides. A zone comprising up to 400 m wide rim of the high and exposed platform has been subject to a process of loosening. A local group of tower-like sandstone blocks was used in the 15th century to build a small rock castle called Drábské Světničky. An extensive landslide that destroyed a substantial part of the village of Dneboh in June 1926, reached in its separating zone up to the toe of marginal rock towers belonging to the complex of Drábské Sv ě tni č ky with the result of local movement activation. Marginal zones of the flat land behind display fresh linear, as well as oval depressions and sinks. Fissure and pseudocarst caves develop. Present activity of the movements has been evidenced by dilatometric measurements on two selected rock objects where movement rates reached 1 to 2 mm per year in average., Jan Rybář, Josef Stemberk and Filip Hartvich., and Obsahuje bibliografické odkazy