Number of found documents: 58
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Calibration of acoustic emission sensors
Kolář, Petr; Petružálek, Matěj
2017 - English
Measurement of acoustic emission (AE) during laboratory experiments – rock sample loading - is an important tool for study of material mechanical properties as well as understanding of modes of its failure. For correct data processing it is necessary to calibrate used AE sensors. The calibration constants can depend on property of individual sensors, on their contact conditions, etc. As there can be a deformation induced charge in sensor contact condition, the calibration constants may vary with time. AE sources can be modeled (in the same way as natural earthquakes) as double couple sources with use of moment tensor (MT) formalism (3x3 symmetric tensor, i.e. 6 independent values, the problem is linear). We adopted method, which enable calibration of an individual station of a seismic network. The method is based on simultaneous determination of MTs and calibration constant(s). During the experiment there were repeatedly measured velocities of elastic waves by ultrasonic sounding, when AE sensors cyclically acted as sources. We processed this data and for each cycle determined calibration constant for all the sensors but one, which is supposed to be 1. The source is supposed to be of single force type, which further reduces number of determined parameters. The evaluation was performed cyclically for all the sensors, the final calibration constants are then the mean values. Keywords: acoustic emission; sensors calibration; ultrasonic sounding Available at various institutes of the ASCR
Calibration of acoustic emission sensors

Measurement of acoustic emission (AE) during laboratory experiments – rock sample loading - is an important tool for study of material mechanical properties as well as understanding of modes of its ...

Kolář, Petr; Petružálek, Matěj
Geofyzikální ústav, 2017

Increase of annual and seasonal air temperatures in the Czech Republic during 1961-2010
Střeštík, Jaroslav; Rožnovský, J.; Štěpánek, P.; Zahradníček, P.
2016 - English
Using the monthly means of air temperatures at 267 stations in the Czech Republic, the long-term change has been estimated at each station for the last 50 years. Annual mean temperatures for the whole country show a considerable increase, more pronounced than that for global temperature, however, supplemented by strong fluctuations from year to year. Long-term changes in air temperatures at different stations and in different regions vary. Stronger increase in air temperatures can be seen in Bohemia, whereas in Moravia temperature increase is not so significant. This difference is more pronounced in the winter, whereas in the summer, the differences are smaller and perhaps of opposite nature. This means that the continentality of the climate in Moravia increases, while in Bohemia it very slightly decreases. Long-term changes depend only marginally on the absolute values of annual mean temperatures at the respective station. The increase of autumn temperatures is considerably lower than that of other seasons. Keywords: air temperatures; long-term change; regions; seasons Available at various institutes of the ASCR
Increase of annual and seasonal air temperatures in the Czech Republic during 1961-2010

Using the monthly means of air temperatures at 267 stations in the Czech Republic, the long-term change has been estimated at each station for the last 50 years. Annual mean temperatures for the whole ...

Střeštík, Jaroslav; Rožnovský, J.; Štěpánek, P.; Zahradníček, P.
Geofyzikální ústav, 2016

Verification of model calculations for the Kaplan turbine design
Polák, M.; Polák, Václav; Hudousková, M.
2016 - English
In order to design a water turbine, the Theory of the Physical Similarity of Hydraulic Machines is used in technical practice. This principle has been known and used by manufacturers of turbines and pumps, but is not available to general public. This paper describes author's calculation program for turbine design that is well accessible to the widest possible range of users of mainly small hydropower sources. Based on the given hydraulic potential (water head and flowrate), the program determines the most suitable turbine type and calculates its main geometric parameters. In addition to numerical results, the program is also endowed with graphic output which renders in true scale hydraulic profiles of rotor blades and guide blades as well as the hydraulic profile of a spiral casing. The process of the Kaplan turbine design is used as an example in this paper. The comparisons of the calculated results with the verified standard 4-K-69 Kaplan turbine confirm the compliance of numerical results with reality. Keywords: blade geometry; calculation program; theory of physical similarity Available at various institutes of the ASCR
Verification of model calculations for the Kaplan turbine design

In order to design a water turbine, the Theory of the Physical Similarity of Hydraulic Machines is used in technical practice. This principle has been known and used by manufacturers of turbines and ...

Polák, M.; Polák, Václav; Hudousková, M.
Geofyzikální ústav, 2016

Detailed analysis of (selected) West Bohemian earthquakes - results and possible geological consequences
Kolář, Petr
2015 - English
At TCP 2011 and 2013 we informed about Interactive tool for determination of parameters of finite seismic source model using Stopping Phases method. Now the crucial part of software is developed and the Tool is in routine operation: events are analysed, values of investigated parameters are obtained and in addition the harvested results seem to yield also information about detailed geological structure in the foci area - such knowledge cannot be obtained by another way unless the exhaustive and expensive prospecting geophysical methods are applied. Namely we processed sets of events from pronounced seismic swarms which occurred in West Bohemia in yrs. 2000, 2008 and under the investigation are 2011 data (2014 data are the challenge for the future). Keywords: West Bohemia seismic swarms; finite seismic source; data processing Available at various institutes of the ASCR
Detailed analysis of (selected) West Bohemian earthquakes - results and possible geological consequences

At TCP 2011 and 2013 we informed about Interactive tool for determination of parameters of finite seismic source model using Stopping Phases method. Now the crucial part of software is developed and ...

Kolář, Petr
Geofyzikální ústav, 2015

Tool for finite seismic source parameters determination - Stopping phases method, ver. 2
Kolář, Petr
2013 - English
A special (interactive) Tool for particular processing of seismograms from West Bohemian seismic region has been already presented (TCP2011); the purpose of the study is to determine the parameter of (simplified) seismic source model. In the present contribution we inform about code current stage, processed data and obtained results (seismic swarms from 2000 and 2008 years were investigated), as well as about particular improvements and development, namely incorporation of (i) more precise onset time determination (with use of signal over-resampling), correction of effect of (ii) anisotropy and (iii) attenuation; the graphical appearance of the Tool has been also tuned. Keywords: seismograms; West Bohemia region; data processing Available at various institutes of the ASCR
Tool for finite seismic source parameters determination - Stopping phases method, ver. 2

A special (interactive) Tool for particular processing of seismograms from West Bohemian seismic region has been already presented (TCP2011); the purpose of the study is to determine the parameter of ...

Kolář, Petr
Geofyzikální ústav, 2013

New interactive software for seismic data processing
Doubravová, Jana; Horálek, Josef
2013 - English
Seismon is an open source software package under GNU General Public Li- cense developed by Stefan Mertl (TU Wien). It is designed as a modular pro- gram with de ned interface for speci c types of modules. This gives program- mer rules how to add new tools easily without disturbing the program integrity. Seismon is written in MATLAB and all input and output data are stored in MySQL database which can be accessed by more Seismon users simultaneously. Seismon is initially equipped with tools for communication with the database, various waveform le conversions, and basic tools for data analysis and visual- ization. To use this software for routine processing of data from local seismic network in West Bohemia (WEBNET), some adaptations had to be done, and the modi ed program was called Seismon_WB. There had to be put a great emphasis on user friendliness which required to de ne keyboard shortcuts, add status bars directly displaying current possibilities and properties, or extract the most important functions out of structured menus to main window as GUI components. Keywords: MATLAB; seismic data processing; Seismon_WB Available at various institutes of the ASCR
New interactive software for seismic data processing

Seismon is an open source software package under GNU General Public Li- cense developed by Stefan Mertl (TU Wien). It is designed as a modular pro- gram with de ned interface for speci c types of ...

Doubravová, Jana; Horálek, Josef
Geofyzikální ústav, 2013

The increase of the air temperatures observed in different European localities during 1951-2010
Střeštík, Jaroslav
2012 - English
Uninterrupted series of annual mean temperatures from 72 European observatories have been processed. The temperature at these stations increased in general more than global temperature, but with considerable fluctuations. The increase at the individual stations is very different. It depends very slightly on the geographic longitude. Stations where lower temperature increase has been observed are located mainly at the Atlantic coast, those with higher increase being mainly in inland. There are, however, many exceptions from this rule, but the gross character of the distribution of stations with different temperature increase seems to be clear. Keywords: temperature increase; coastal regions; continental regions Available at various institutes of the ASCR
The increase of the air temperatures observed in different European localities during 1951-2010

Uninterrupted series of annual mean temperatures from 72 European observatories have been processed. The temperature at these stations increased in general more than global temperature, but with ...

Střeštík, Jaroslav
Geofyzikální ústav, 2012

A tool for determination finite seismic source parameters via stopping phases method
Kolář, Petr
2011 - English
We present a special (interactive) tool for particular processing of seismograms from West Bohemia region. The purpose of the data investigation is to determine the parameter of (simplified) seismic source. There are given basic information about the seismic region, its activity, about the used method and about its particular realization. The developed tool is described including screen shots of the graphical interfaces. Keywords: seismograms; West Bohemia region; data processing; zpracování dat Available at various institutes of the ASCR
A tool for determination finite seismic source parameters via stopping phases method

We present a special (interactive) tool for particular processing of seismograms from West Bohemia region. The purpose of the data investigation is to determine the parameter of (simplified) seismic ...

Kolář, Petr
Geofyzikální ústav, 2011

Robust solver of a system of nonlinear equations
Růžek, Bohuslav; Kolář, Petr; Kvasnička, M.
2009 - English
ANNIT (Artificial Neural Network Inversion Tool) is solver of a set of non- linear equations. It is implemented in MATLAB and Scilab. ANNIT is based on numerical approximation of mapping the right hand sides residuals of the original set of equations to searched parameters. A population of individuals is used for building such approximation. The shape, location and size of this population is adaptively changed during the inversion depending on the convergence of the solved problem. ANNIT has been thoroughly tested by using a set of standard problems and also by using selected geophysical problems (localization of the earthquake hypocenter, magnetotelluric inversion, inversion of group velocities of surface waves etc.). Keywords: inverse problem; nonlinear equation solver; rovnice; lineární rovnice Available at various institutes of the ASCR
Robust solver of a system of nonlinear equations

ANNIT (Artificial Neural Network Inversion Tool) is solver of a set of non- linear equations. It is implemented in MATLAB and Scilab. ANNIT is based on numerical approximation of mapping the right ...

Růžek, Bohuslav; Kolář, Petr; Kvasnička, M.
Geofyzikální ústav, 2009

MEPL2 - interactive-batch tool for full seismic MT plotting
Kolář, Petr
2007 - English
Prezentujeme nový interaktivní program pro vykreslování plných momentových tenzorů. Kromě řady jiných vlastností je možný buď interaktivní nebo dávkový vstup dat. New interactive program for full seismic moment tensors plotting is presented. Among other features, interactive as well as batch data input is supported. Keywords: MATLAB program; MEPL 2 program; moment tensors; programy; hybnost Available at various institutes of the ASCR
MEPL2 - interactive-batch tool for full seismic MT plotting

Prezentujeme nový interaktivní program pro vykreslování plných momentových tenzorů. Kromě řady jiných vlastností je možný buď interaktivní nebo dávkový vstup dat....

Kolář, Petr
Geofyzikální ústav, 2007

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