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262. Implementation of the Vondrak's smoothing in the combination of results of different space geodesy techniques
- Creator:
- Štefka, Vojtěch and Ivan Pešek
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodezie, geodesy, Earth orientation parameters, combination of space geodesy techniques, Vondrak’s smoothing, 7, and 551
- Language:
- English
- Description:
- Four space geodesy techniques, namely VLBI, GPS, SLR and Doris, produce Earth orientation parameters (EOP) and station coordinates independently of each other. A method to combine them in a non-rigorous way (as described elsewhere) was modified by implementing Vondrak’s smoothing. It replaces a simple constraint to tie EOP at adjacent epochs by a more general expression defining smoothness of the resulting curves. This gives the method better stability of derived EOP. The new method was tested on GPS, VLBI and SLR data covering a one-year interval. The results were compared with the results of the original method and with the IERS c04 solution. The former indicates the effect of modification while the latter shows differences of this particular solution from the official IERS series, Vojtěch Štefka and Ivan Pešek., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
263. Influence of chemical and mineralogical composition of metakaolin on mortar characteristics
- Creator:
- Velosa, Ana Luisa, Rocha, Fernando, and Veiga, Rosário
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, metakaolin, mineralogie, malty, mineralogy, mortar, chemical composition, 7, and 551
- Language:
- English
- Description:
- Three different metakaolins processed by a Portuguese factory were studied aiming to assess the influence of chemical and mineralogical composition of metakaolin on mortar characteristics. Mineralogical analysis of both the fine and clay fractions was carried out by X-ray diffraction. Chemical composition (major elements) was analyzed by X-ray fluorescence. Mineralogical composition reveals some significant differences between the studied samples, in both analyzed fractions, metakaolin 2 being richer in kaolinitic minerals. From a chemical point of view, siliceous content is always high (aroun d 60 %) as well as Al2O3 content (around 30 %); once again metakaolin 2 is the one richer in Al2O3 and poorer in sodium and potassium. Metakaolin from the three different batches was incorporated in lime mortars in order to produce a pozzolanic reaction and hence enable them to harden in high relative humidity conditions or, when access to CO2 is limited, as in the case of mortars supporting glazed tiles. Mortars with the same volum etric ratio were tested for flexural and compressive strength at ages of 28 and 90 days, and the module of elasticity was dete rmined. A relation between the mechanical strength achieved by lime mortars with the addition of metakaolin from different batches and metakaolin mineral and chemical composition was assessed. The knowledge of the influence of the metakaolin com position on the strength of the mortars is an important step in improving their performance and extending their application., Ana Luisa Velosa, Fernando Rocha and Rosário Veiga., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
264. Influence of dislocations on bumps occurrence in deep mines
- Creator:
- Petr Procházka, Jiřina Trčková, and Lok, Tat Seng
- Format:
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- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, numerické modelování, doly, numerical modeling, mines, free hexagon method, deep mines, bumps occurrence, 7, and 551
- Language:
- English
- Description:
- The problem of bumps occurrence in deep mines during the long wall mining appears to be one of the most serious one in the design of engineering of mining. The bumps are caused for various reasons, but basically it is an aftermath of the accumulated energy, which is released under some unfavorable conditions. In this paper the influence of given dislocations and their slope in a coal seam are studied based. The numerical tool is the free hexagon method. This method belongs to a set of discrete element methods and enables us to define and calculate stresses in a natural way along the interfacial boundaries of adjacent particles (elements). Since the bumps are affected by a possible slip along the dislocations, dynamical response has to be taken into account. The velocity of excavation of the mine is considered by successive change of values of Eshelby’s forces on the face of the wall., Petr Pavel Procházka, Jiřina Trčková and Tat Seng Lok., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
265. Influence of particle shape on the viscosity of kaolin suspensions
- Creator:
- Eva Gregorová, Willi Pabst, and Bouchet, Jean-Baptiste
- Format:
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- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, kaolin, viskozita, viscosity, particle shape, 7, and 551
- Language:
- English
- Description:
- The influence of particle shape (aspect ratio) on the intrinsic viscosity is investigated, taking three Czech kaolin products (floated kaolins) as paradigmatic examples. An average aspect ratio is obtained for each kaolin from a comparison of particle size measurements using sedimentation and laser diffraction. The intrinsic viscosity is obtained by a multistep procedure: firstly, flow curves are recorded for each kaolin with the optimum deflocculant concentration, secondly, the (apparent) relative viscosities read off from the flow curves are plotted against the kaolin volume fraction and, thirdly, these data are fitted using the Krieger relation to obtain the intrinsic viscosity in the asymptotic dilute limit. It is shown that the data determined with the method proposed are within the Jeffery and Brenner bounds and that an average aspect ratio of about 20 (17-22) results in an intrinsic viscosity of about 10 (7-13), compared to 2.5 for spherical particles. Although currently th e measurement precision is not suffi cient to seriously assess the influence of Brownian motion, the method can principally be used to predict the intrinsic viscosity when the average aspect ratio of the system (and its particle size distribution) is known, and vice versa., Eva Gregorová, Willi Pabst and Jean-Baptiste Bouchet., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
266. Influence of temperature changes on the Vladislav Hall vault
- Creator:
- Petr Fajman, Jiří Máca, and Pavel Beran
- Format:
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- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, klenby, haly, teplota, vaults (architecture), halls, temperature, rib, rod, loading, 7, and 551
- Language:
- English
- Description:
- The vault in Vladislav Hall is a structural masterpiece of great historical value. Its structural analysis revealed that the permanent load exerted by its self weight is uniformly transmitted into the vaults and ribs without any potential crack appearance. The topical issue, however, is its response to temperature changes with respect to actual effects. Computations show that temperature changes may cause problems., Petr Fajman, Jiří Máca and Pavel Beran., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
267. Instrument for monitoring spectral acceleration on response seismic ground motion
- Creator:
- Buben, Jiří and Rudajev, Vladimír
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, zesilovače, elektronika, amplifiers, electronics, AD converter, damping, selective filter, transfer function, inverted pendulum, vibration acceleration, spectral response, seismic recorder, 7, and 551
- Language:
- English
- Description:
- For investigation of influence of various subsoil geological structures on spectral acceleration amplitudes of foundation soil it is necessary to continue in long time monitoring of near seismic events by using of large number of field accelerometers. The new special apparatus for automatic recording of spectral acceleration response was constructed. Principle of this apparatus is reverse pendulum with piezoelectric converter. This simple construction makes possible production numerous series with small requirements on capital expenditure and installation. The function of developed apparatus prototype was field-tested in station Prague - Květnice. Various seismic signals were recorded and also response amplitude of earthquake with focus near Červený Kostelec (10 October 2005, 10 : 51 : 57.4 ; M = 3.4; R = 156 km; φ = 50.47; λ = 16.07)., Jiří Buben and Vladimír Rudajev., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
268. Instrumental Meteorological Measurements in Moravia up to the End of the Eighteenth Century /
- Type:
- text and monografie kolektivní
- Subject:
- Geologie. Meteorologie. Klimatologie, Mag z Maggu, František Alois,, Kiesswetter, Aloys Ferdinand,, Gaar, Josef,, Beck, Felix,, meteorologie, měření meteorologická, počasí, klimatologie historická, vědy o neživé přírodě, přírodní prostředí, astronomie, and české země 1740-1792
- Language:
- English, Latin, and German
- Rights:
- unknown
269. Interactive seismic viewer "OP": short review
- Creator:
- Kolář, Petr
- Format:
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- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, seizmologie, seismology, interactive seismic viewer, seismogram processing, MATLAB, 7, and 551
- Language:
- English
- Description:
- We introduce an interactive seismic viewer "OP" (developed in MATLAB platform), primary designated for detailed processing of selected events. Few examples of graphical outlook are presented (main display window, particle motion diagram, etc.), available tools are briefly described, uncommon special tools (simultaneous display of original and filtered signal or time-spatial correlation of seismogram components) are emphasized. Features of the viewer are discussed, some programming solutions are also mentioned., Petr Kolář., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
270. Investigation of environmental influences to the precise GNNS solutions
- Creator:
- Bogusz, Janusz, Figurski, Mariusz, Kroszczyński, Krzysztof, and Szafranek, Karolina
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, GPS (navigační systém), GPS (navigation system), GLONASS, ASG-EUPOS, environmental influences, 7, and 551
- Language:
- English
- Description:
- The results presented in this paper concern investigation of environmental influences to GNNS coordinates on the example of ASG-EUPOS network. The problem of the impact of environmental effects is crucial for observing gravity. Satellite systems are not as susceptible to changes in local hydrology or atmospheric effects, although significant influences are clearly visible in the change of coordinates. The authors analyzed daily and sub-daily solutions (geocentric coordinates) in the context of different disturbances to eliminate sites suffering from poor quality for further researches (e.g. data from the most reliable ASG-EUPOS stations will be used for investigating the correlation of their movements with the lithosphere deformations on territory of Poland). There are many doubts regarding proper antennas’ placement - as they are mostly placed on the roofs, there were questions if data from these sites can be used for scientific purposes like velocity estimations or geodynamical researches. Analysis of daily solutions was supposed to prove that the majority of Polish sites give fully valuable data. Some factors that may cause a precision decreasing can be avoided or eliminated in the future. Taking into consideration that GLONASS will be soon fully operational and it will be an alternative for commonly used GPS, the authors made separate elaboration of GPS and GLONASS data. Usage of two different satellite systems holds the potential to increase of solutions’ reliability and eliminate errors that could be possibly related to the specific satellite system. Base on time series of coordinates residual values, systematic errors that could prove geophysical and geodynamical influence on GNSS measurements were investigated. In this elaboration only post-processing observations were taken into account, but the monitoring of the network in the near real-time by means of coordinates’ stability is under development., Janusz Bogusz, Mariusz Figurski, Krzysztof Kroszczyński and Karolina Szafranek., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public