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Measurement of biological structures humidity
Vlk, Jáchym ; Kubásek, Radek (referee) ; Friedl, Martin (advisor)
The work summarizes known methods about measuring liquids and humidity in complicated biological structures. Particular methods and their principles are stated and described here. This work includes description and creation of inductive and capacitive sensor as well as information for creating inductive and capacitive sensor.
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Numerická předpěťová modální analýza kmene
Skokan, Vojtěch
This work is investigating the effect of prestress on the results of the numerical modal analysis of tree stem and the effects of the degree of simplification of the geometry of the numerical model on the values of natural frequencies and modes of natural oscillation. The work aims to create credible numerical models of trunks and to use prestress to induce such a change in the diameter of the trunk that occurs in trees during the diumal cycle, thus simulating the transpiration stress in the trunk. During the work, three different methods of inducing prestress in the trunk are investigated and their impact on the values of the observed frequencies of strain models is assessed. In addition to artificial prestress, the work also assesses the impacts of the co-effect of gravity on the values of natural frequencies. This work is one of the first attempts to investigate the effect of mechanical stress caused by the transpiration flow using numerical simulation and can thus lay the foundation for future research in this field.
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Stanovení ochlazovací funkce stromů v areálu Nadace Partnerství v Brně
Věchetová, Tamara
The urban heat island (UHI) is one of the most important problems in urban landscapes. Trees can reduce the negative impact of UHI through shading and evapotranspiration. Goal of this thesis is to determine the cooling effect of four Norway maples (Acer platanoides) in Nadace Partnerství, the area of Otevřená zahrada in Brno. Sap Flow of these trees was measured with trunk heat balance method (THB) and has taken place during the summer of 2017. It was possible, due to seasonal measurements of tree sap flow, to calculate, how much energy was consumed for process of transpiration. The consumed energy was calculated through specific latent heat which is 2450 kJ/l. Trees were able to transpirate up to 3 685 litres of water per month (June). Monthly, 28,3 to 32,8% energy was consumed for the process of transpiration. If the trees were absent, the energy would be used for heating of the urban surface thus increasing the surrounding air temperature.
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Determination of stress of Norway spruce by direct methods
Krejza, Jan ; Světlík, J. ; Bellan, Michal ; Horáček, Petr
The aim of this methodology is to introduce methods of forest ground monitoring leading to evaluation of Norway spruce tree vitality. Certified methodology describes: measuring of the stem surface temperature by thermography, measuring of the sap flow, measuring the stem diameter fluctuation and by the analysis of xylogenesis and wood morphology. Emphasis was placed on the detection of the stress reaction before occurrence of the visual symptoms. The aim of this methodology is to present a comprehensive set of methods for measuring ecopysiological activity of a tree and to determine its health status. The goal of this methodology is to provide a unique tools for foresters and for forest management for direct and precise evaluation of health status of individual trees, but also a whole complexes of forest from the ground perspective. The individual methodological approaches are defined, can be used in practice and their interpretation is unambiguous. The novelty is based on the direct measurement of the physiological activity of the individual trees, which exclude any degree of subjectivity in the evaluation process.
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Measurement of biological structures humidity
Vlk, Jáchym ; Kubásek, Radek (referee) ; Friedl, Martin (advisor)
The work summarizes known methods about measuring liquids and humidity in complicated biological structures. Particular methods and their principles are stated and described here. This work includes description and creation of inductive and capacitive sensor as well as information for creating inductive and capacitive sensor.
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Numerická analýza vlivu variability toku vody na teplotní pole během ohřevu bělové části dřeva stromu
Opletal, Libor
This thesis compares two methods for sap flow calculation during continuouslinear heating in tree sapwood. LHB method has substantially better results. For this analysis, we used three trees with different radial pattern -- Cupressusarizonica, OleaeuropaeaaPopulusinteramericana -- with radius 0,14 m, sapwood 0,08 m. We solved the equations with Qw from 0,008kg.m-2s-1 to 0,08 kg.m-2s-1 and thermal conductivity lambda 0,3 W.m-1K-1and 0,4 W.m-1K-1. The output of this thesis is the comparison of results between methods HFD and LHB, especially influence of inhomogeneous radial pattern.
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Srovnání stacionárního a nestacionárního modelu kondukce a konvekce tepla v bělové části dřeva stromu během ohřevu
Vopařil, Tomáš
This thesis compare stationary and nonstationary numeric model of conduction and convection of heat in sapwood part of tree. Numeric models are testing with diferent moistures of sapwod and diferent sapflows. There are tested HFD and LHB methods in models which are compared each other. LHB method has substantially better results. Stationary and nonstationary models are almost unchanged in decreasing sapflow. Divergency of individual models rises at increasing sapflow. There is nonstationary method departed from stationery method in the initial sapflow.
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