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The X-ray CT lab and the research at the Institute of Geonics AS CR
Souček, Kamil; Staš, Lubomír
2014 - English
In recent decades, non-destructive methods of materials analysis (Desrues 2006) have been used increasingly for the study of different kinds of materials. Especially, it concerns the method of the X-ray computed tomography (CT). This technique was invented in 1970's (Hounsfield 1972) and it quickly became an indispensable part of medicine. In the 1980's, this success in medicine encouraged the research and development of the X-ray CT applications in the field of materials engineering and consequently also in the field of geomaterials (Otani, Obara 2004). Nowadays, many applications are possible due to high resolution of individual building units in the tomographic cross-sections (so called voxels) with dimensions of units or tens of micrometres. To get this resolution, the use of the 2D and the 3D high-resolution X-ray CT, or the micro-CT with micro-focal sources of X-rays, and suitable linear or flat (2D) X-Ray detectors are preferred.
Keywords:
X-Ray computed tomography; non-destructive investigation of geomaterials; X-ray CT lab; rentgenové záření; materiály
Available in digital repository of the ASCR
The X-ray CT lab and the research at the Institute of Geonics AS CR
In recent decades, non-destructive methods of materials analysis (Desrues 2006) have been used increasingly for the study of different kinds of materials. Especially, it concerns the method of the ...
Stability of suspension bridges in lateral wind
Malík, Josef
2014 - English
The collapse of the original Tacoma suspension bridge has been studied in many papers. On 7 November 1940 around 10 a.m. the torsional oscillations appeared on the deck of the original Tacoma bridge after the loosening of one midspan cable band, which resulted in the lateral asymmetry of the construction. It seems that the loosening of the midspan cable band had a significant impact on the behavior of the bridge and in the end it resulted in the collapse.
Keywords:
stability; suspension bridges; torsional oscillations
Available in a digital repository NRGL
Stability of suspension bridges in lateral wind
The collapse of the original Tacoma suspension bridge has been studied in many papers. On 7 November 1940 around 10 a.m. the torsional oscillations appeared on the deck of the original Tacoma bridge ...
Geosite and geomorphosite assessment for geotourism purposes: a case study from the Vizovická vrchovina Highland, Eastern Moravia
Kirchner, Karel; Kubalíková, L.
2014 - English
Contribution deals with the problem of geodiversity, geoheritage and possibilities of their assessment for geotourism purposes. Geological, geomorphological and pedological sites are the most important resource for the geotourism activities. To find out which site can be used, it is necessary to identify, describe and assess various sites using a suitable assessment methodology. Based on the definition and concepts of geotourism and the assessment methods already used for geomorphosite assessment, authors propose five groups of assessment criteria. The method was used for assessing selected sites in the Vizovická vrchovina Highland.
Keywords:
geodiversity; numerical assessment; Outer Western Carpathians
Available in a digital repository NRGL
Geosite and geomorphosite assessment for geotourism purposes: a case study from the Vizovická vrchovina Highland, Eastern Moravia
Contribution deals with the problem of geodiversity, geoheritage and possibilities of their assessment for geotourism purposes. Geological, geomorphological and pedological sites are the most ...
Optimization methods for inverse problems with energy norm
Hrtus, Rostislav; Haslinger, Jaroslav; Blaheta, Radim
2014 - English
The paper deals with the application of the energy norm in the inverse problem which is based on a minimization of a nonlinear least squares function. Three different parameter distribution examples are solved by the steepest descent, nonlinear conjugate gradient and Newton methods. Efficiency comparison is also presented.
Keywords:
optimization methods; parameter distribution; Newton methods
Available in a digital repository NRGL
Optimization methods for inverse problems with energy norm
The paper deals with the application of the energy norm in the inverse problem which is based on a minimization of a nonlinear least squares function. Three different parameter distribution examples ...
Slightly generalized regular space decompositions
Kolcun, Alexej
2014 - English
Space decomposition methods represent an important part of numerical modelling process. In many applications it is suitable to use the simplest case of decomposition { regular rectangular grid: the whole raster graphic concept can be seen from this point of view. Dierent raster concept, based on regular hexagonal mesh, is analyzed e.g. in [18]. Generalized task { decomposition of the space to the set of the identical elements have been presented in various research areas since a long time, and it is connected with Hilbert's 18th problem [9], [10].
Keywords:
space decomposition methods; numerical modelling; discretization
Available in a digital repository NRGL
Slightly generalized regular space decompositions
Space decomposition methods represent an important part of numerical modelling process. In many applications it is suitable to use the simplest case of decomposition { regular rectangular grid: the ...
Geo-oriented mathematical modelling: multiphysics and multiscale
Blaheta, Radim
2014 - English
This contribution is aimed at a brief introduction to two important aspects of nowadays geo-oriented mathematical modelling: multiphysics and multiscale. Moreover, these types of modelling are illustrated on problems currently solved at the Institute of Geonics AS CR.The multiphysics means modelling of coupled physical phenomena. In the case of the geotechnical engineering, it is typically modelling of coupled thermo-hydro-mechanical (THM) processes, in other engineering branches, we can consider similar models, e.g. coupling of electric and mechanical phenomena. The modelling of coupled processes is particularly involved in modelling of sealing and plugging effects of bentonite barriers used in the design of underground repository of spent nuclear fuel. At present, the team at the Institute of Geonics is involved in the solution of Task A of the Decovalex 2015 project aimed at modelling in-situ SEALEX experiments, which were performed in Tournemire underground laboratory in France.
Keywords:
cyclic loading; thermal loading; dynamic loading; creep; underground opening; cyklické zatěžování; tečení
Available in digital repository of the ASCR
Geo-oriented mathematical modelling: multiphysics and multiscale
This contribution is aimed at a brief introduction to two important aspects of nowadays geo-oriented mathematical modelling: multiphysics and multiscale. Moreover, these types of modelling are ...
The history of measurement of rock mechanical properties at the Institute of Geonics AS CR
Konečný, Pavel; Blaheta, Radim
2014 - English
The rock testing and evaluation of parameters for description of rock behaviour is an important part of the research at the Institute of Geonics AS CR since its foundation as an independent institute of the Czechoslovak Academy of Sciences in 1982. Focusing on mechanical testing, the first testing device, the hydraulic press EDZ 100H made in GDR with maximum force 1000 kN, was acquired in 1980, when only a branch of the Mining Institute existed in Ostrava. This equipment was substantially extended in the eighties by two „small“ mechanical presses FPZ 100 (max. force 100kN) and FPZ 10 (max. force 10kN) purchased in 1987 from GDR. But a really great progress came with the mechanical press ZWICK 1494 (500 kN) controlled by computer with a possibility of recording and processing the data. This press was bought from ZWICK Ulm (FRG) in 1985. The deformation measurement was realized by the dial test indicators. The described equipment was used for rock testing with focus on elastic behaviour and uniaxial strength limits, which were required for solving engineering problems mostly related to the coal mining.
Keywords:
rock testing; measurement under uniaxial and triaxial loading; permeability tests; zkoušení; mechanické lisy
Available in digital repository of the ASCR
The history of measurement of rock mechanical properties at the Institute of Geonics AS CR
The rock testing and evaluation of parameters for description of rock behaviour is an important part of the research at the Institute of Geonics AS CR since its foundation as an independent institute ...
High performance computing in micromechanics
Blaheta, Radim; Hrtus, Rostislav; Jakl, Ondřej; Starý, Jiří
2014 - English
By micromechanics we understand analysis of the macroscale response of materials through investigation of processes in their microstructure. Here by the macroscale, we mean the scale of applications, where we solve engineering problems involving materials like different metals and composites in aircraft design or rocks and concrete in a dam construction. Different applications are characterized by different characteristic size. At macroscale the materials mostly look as homogeneous or they are idealized as homogeneous or piecewise homogeneous. A substantial heterogeneity is hidden and appears only after more detailed zooming view into the material.
Keywords:
analysis on CT scans; high resolution finite element solution; boundary value problems; solution of inverse problems
Available in a digital repository NRGL
High performance computing in micromechanics
By micromechanics we understand analysis of the macroscale response of materials through investigation of processes in their microstructure. Here by the macroscale, we mean the scale of ...
Inner Structure of Functionala Region: Theoretical Aspects
Erlebach, M.; Klapka, Pavel; Halás, M.; Tonev, P.
2014 - English
The contribution addresses theoretically the inner structure of functional region. It defines types of functional regions on the basis of selected criteria regarding their inner structure. As classification criteria a number of cores in a region, their hierarchical importance and ch aracter of interaction relationships between them and within a region have been employed. A study of functional regions is not important only for geography, but also for regional and spatial science and for planning practise.
Keywords:
functional region; inner structure; types of regions
Fulltext is available at external website.
Inner Structure of Functionala Region: Theoretical Aspects
The contribution addresses theoretically the inner structure of functional region. It defines types of functional regions on the basis of selected criteria regarding their inner structure. As ...
Texture of cokes in relation to parameters of coal and coke
Pěgřimočová, J.; Kožušníková, Alena
2013 - English
The article presents a proposal of the simplified classification of textures of coke and the relationship between the texture parameters of coke both coal, from which the coke was made, and properties of the coke.
Keywords:
texture of cokes; coal; phase carbon forms
Available in a digital repository NRGL
Texture of cokes in relation to parameters of coal and coke
The article presents a proposal of the simplified classification of textures of coke and the relationship between the texture parameters of coke both coal, from which the coke was made, and ...
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