|
| |
|
| |
|
| |
|
| |
|
|
Selected Mechanical Wood Properties of Douglas Fir from Sites in the Czech Republic
Pilař, Ondřej ; Zeidler, Aleš (advisor) ; Holeček, Tomáš (referee)
Abstract
Introduced tree species are still undoubtedly, despite the current short-term politico-economic and environmental turbulences, an object of interest of the Czech forestry sector. Worldwide the most important tree species, and thus both in the areas
of its original extension and in the large regions where it was successfully introduced,
is the Douglas fir (Pseudotsuga menziesii), which is considered as one of the most perspective tree species. Information about the quality of its wood from our territory
is missing for the time being.
That´s why the aim of this work was to evaluate the quality of Douglas fir wood from different regions of the Czech Republic through selected mechanical properties. Especially the compressive strength, impact strength, flexural modulus and flexural strength were determined by standardized procedures. As well as, the variability
of the trunk features and that one of the locality were taken in consideration.
The final results of the mechanical features compared with the values measured on the wood from the original extension areas are better in compression strength, similar in flexural strength and slightly worse in the flexural modulus.
Comparing the resultant values of Douglas fir with the values of domestic spruce, the Douglas fir shows better values, apart from the values of flexural modulus, which are higher in case of the spruce.
A statistically significant difference between the location and the measured feature is demonstrated only in the elastic modulus and density. At the variability
in frame of the trunk there was found a statistically significant difference between
the vertical and horizontal position of the trunk and all the measured features. At the same time, the value of the measured feature increases together with increasing position from the pulp.
|
|
|
Hemodynamic model in effective brain connectivity analysis using fMRI
Holeček, Tomáš ; Harabiš, Vratislav (referee) ; Lamoš, Martin (advisor)
Modeling of hemodynamic response based on changes of synaptic activity is used for mapping active areas of the brain or functional organization of the brain using functional magnetic resonance imaging. Hemodynamic model is one of the methods for modeling hemodynamic response. Balloon model is the main part of the hemodynamic model. Hemodynamic model is used in the mapping active areas using general linear model and in the effective brain connectivity analysis using dynamic causal modelling. This bachelor´s thesis is focused on description of the hemodynamic model, its parameters and impact of every single parameter of the hemodynamic model on its response.
|
|
|
Scaling of arterial input function in DCE-MRI
Holeček, Tomáš ; Kolář, Radim (referee) ; Kratochvíla, Jiří (advisor)
Perfusion magnetic resonance imaging is modern diagnostic method used mainly in oncology. In this method, contrast agent is injected to the subject and then is continuously monitored the progress of its concentration in the affected area in time. Correct determination of the arterial input function (AIF) is very important for perfusion analysis. One possibility is to model AIF by multichannel blind deconvolution but the estimated AIF is necessary to be scaled. This master´s thesis is focused on description of scaling methods and their influence on perfussion parameters in dependence on used model of AIF in different tissues.
|
|
|
Scaling of arterial input function in DCE-MRI
Holeček, Tomáš ; Kolář, Radim (referee) ; Kratochvíla, Jiří (advisor)
Perfusion magnetic resonance imaging is modern diagnostic method used mainly in oncology. In this method, contrast agent is injected to the subject and then is continuously monitored the progress of its concentration in the affected area in time. Correct determination of the arterial input function (AIF) is very important for perfusion analysis. One possibility is to model AIF by multichannel blind deconvolution but the estimated AIF is necessary to be scaled. This master´s thesis is focused on description of scaling methods and their influence on perfussion parameters in dependence on used model of AIF in different tissues.
|
|
| |
|
| |
guest ::
RSS feed.