National Repository of Grey Literature 54 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Způsoby likvidace Lýkožrouta smrkového
ŘÍHA, Jan
The bachelor thesis deals with the morphology and life cycle of the spruce lichen-eater. The main focus is on measures to combat the spruce lichen-eater and an overview of such techniques and technologies designed for that. Here I describe the issue of swarming, wintering and what bark beetles have natural enemies. The bachelor's thesis describes how to treat the lichen-eater, how to prevent it, and mainly there are instructions on how to use individual technologies for its disposal. It is a mechanical technology of liquidation or even chemical liquidation. There is also a research overview of articles from international databases and extracts from them in my words. The aim of this work is to create a research overview of the biology and methods of disposal of the spruce lichen-eater.
Study of quantitative parameters of Norway spruce needle structure under the effect of elevated CO₂ concentration and different irradiance
Kubínová, Zuzana ; Lhotáková, Zuzana (advisor) ; Urban, Otmar (referee) ; Gebauer, Roman (referee)
Zuzana Kubínová: Study of Quantitative Parameters of Norway Spruce Needle Structure under the Effect of Elevated CO2 Concentration and Different Irradiance, Doctoral Thesis, Prague 2019 Abstract Atmospheric concentration of CO2 is increasing, while its influence on plants is still not fully elucidated. Norway spruce (Picea abies L. Karst.) is an abundant conifer tree in European temperate and boreal forests, which behave as carbon sink in the global carbon cycle. The physiological response to elevated CO2 concentration may be interconnected with changes in leaf anatomy and morphology. Needle structure is also determined by other factors in addition to CO2 concentration, irradiance being the most important one. Thus, effect of irradiance was also included in our studies. The effects of elevated CO2 concentration and irradiance on Norway spruce needle structure were studied using new applications of well-established quantitative methods and novel methods enabling effective and unbiased analysis of needle structural traits. The General Procrustes analysis showed to be effective for needle shape on cross section comparison and the disector method proved to be suitable for chloroplast number estimates. The influence of elevated CO2 concentration and different irradiance on needle structure was studied at two...
Establishment and growth of spruces in reclaimed and unreclaimed plots on heaps after coal mining
Spurná, Veronika ; Frouz, Jan (advisor) ; Reif, Jiří (referee)
Coal is the most important raw material mined in our country. The mining acitivity creates huge impact on the landscape. The aim of the thesis is to compare the attachment of spruces on spoil tips created by coal mining and their growth during spontaneous succession and reclamation. The studied non-recultivated areas are overgrown with spontaneous vegetation consisting mainly of willow (Salix caprea), white birch (Betula pendula) and aspen poplar (Populus tremula L.). The reclaimed area only consists of planted Norway spruce (Picea abies). The density of localities, age and height structure, layout on terrain waves and distance from the edge of the dump were studied. Spruces were also mapped using GPS. The density of spruce vegetation on reclaimed areas is significantly higher than on succession, however, their growth is slower. On non-reclaimed areas, the growth of already attached spruces is significantly faster than on reclaimed areas. The results show a higher attachment of spruces on the slopes of the waves, especially on the northern leeward side, rather than in the troughs or on the peaks. The results show the possibility of undercutting succession areas with climax trees as a promising method of reclamation. Keywords: spruce, succession, reclamation, establishment of trees, density of trees
Analysis of methods for determining wood moisture by non-destructive methods
Změlík, Jiří ; Zach, Jiří (referee) ; Vaněrek, Jan (advisor)
Subject of this bachelor thesis is the analysis and comparison of hygrometers considering their price, availability and applicability. Theoretical part compared available types of hygrometers based on their operating principle. Subsequently, resistance, capacitive and microwave portable hygrometers were compared in more detail. There were five reviewed hygrometers in total, with three of them capacitive and one of each resistance and microwave. The measurement was performed on beech and spruce trees at gravimetrically known humidity, ranging from extremely low to extremely high values (even out of bounds recommended by the manufacturer). The evaluation of the methods was performed according to the Saaty´s AHP method. Hygrometers were then selected by their optimization. After the experimental part, the suitability of individual methods was determined. The best method was capacitive, followed by resistance and the worst microwave method.
The analysis of acoustic properties of innovative wood-based materials
Svojanovský, Jan ; Nop, Patrik (referee) ; Jirásek, Ondřej (advisor)
The content of this work is research of innovative wood-based materials in the acous-tic perspective. Basically, the goal is to determine the influence of the internal structure of the wood-based material on variables, which are sound speed, acoustic resistance, or acous-tic constant. In total were measured 15 samples, each one was made in a different way. Each sam-ple was weighted, and the length of its sides was measured. By using the ultra sonic timer, it was measured the time of the sound impulses, which go through the samples in all of their axes for the purpose of observation the influence the fibers on speed of sound in the materi-al. The next thing to do was to determine another magnitude, which describe acoustic of the material. All measurements were taken in room conditions (room humidity). Six of the sam-ples, which were randomly selected from those 15 samples, were measured once again after two weeks. In those two weeks were all the samples saved in air-conditioned place in which was the room humidity distinct lower. In the end all the samples were compared with each other and they were also com-pared with materials which are commonly used in production of musical instruments or acoustic components. Possible use in the music industry was assigned to each sample.
Ověření experimentální metodiky vyhledávání hnilob založené na impedanční tomografii v porostech smrku ztepilého (Picea abies L.)
Vincour, Matěj
The purpose of this Bachelor thesis was to monitor health of the Norway spruce (Picea abies L.), which is currently strongly endangered by biotic and abiotic factors. For the health detection of the woods are used non-destructive diagnostic machines. Measuring were in the territory of the Training forest enterprise Masarykův les Křtiny, Polesí Habrůvka. For the measuring were used acoustic tomography, which is based on passage of sound waves and electrical impedance tomography which is also used for detection rot electric resistance. Using this tomography was evaluated the presence of the rot in the trunk and its range. Total number of the trees measured by acoustic tomography was 30 trees, 15 trees were measured by electrical impedance tomography. For determination of the accuracy of measurement electrical impedance tomography, were compared the results with the specific tree cut-outs. For measurement of acoustic tomography was observed velocity changes because of the damages. Thanks to the detection rots and cavities in the trunk was also partly determined the stability of the tree.
Dendrochronologické datování a stavebněhistorické hodnocení krovu kostela svatého Jakuba Staršího v Omicích (okres Brno-venkov)
Tetur, Vladan
The aim of this work is determination of the age of roof construction of the Roman Catholic church of St. Jacob the Elder in Omics, using dendrochronological analysis. In this work is describes a standard procedure for dendrochronological dating from the sampling, editing, measurement and dating. There is also incorporated building-historical development of the building, where the effort is to determine chronologically the development of the whole building from historical literary sources. The roof of the church is mainly built of fir wood, except for two old oak binding beams, and binding beam belfry which is spruce. The fir trees used on the roof over the presbytery were cut away in autumn or winter in 1874 or in winter at the beginning of 1875. The oak trees used on the old binding beams were cut away after 1765. The fir trees above the main ship were cut away after 1917. The spruce tree used for the binding beam of the belfry was cut away in the autumn or winter of 1927 or in the winter of early 1928. Trees used for the bell tower failed to date. Using dendrochronological dating and anatomical wood building analysis, we were able to supplement or refine the historical development of the church.
Povrchové úprava dřevěného obložení dřevostavby
Šindler, Miroslav
This diploma thesis shall address the surface treatment of wood paneling of log homes. Samples representing wooden paneling were painted and exposed at two different locations in different climate conditions. The first set of samples was exposed on the premises of the Mendel University in Brno and the other one in Berkhamsted in UK. The placement of individual samples sample took place on the premises of the university where we were provided with iron racks on which samples remained for two years. Over the years, the above-mentioned measurement was performed on the roughness, lightfastness and gloss of coating material using respective devices. Samples, which were exposed in the UK, were inserted into the pre-formed racks made of oak wood and they were measured at the start of their exposure and after the completion of the experiment. That experiment shall show the changes of aesthetic and physical and mechanical properties which can be observed in individual plank lining. In our work we deal primarily with the change of the color and roughness of thematerial. As we know that wood exposed to external weather conditions is stressed by various factors, biotic as well as abiotic factors, the structure and appearance under these conditions are changing over time. These changes are also affected by the exposure of a product or the place where the test set of samples is exposed. Consequently, we will discuss the changes in color and surface roughness before and after the exposure.
Porovnání klasických a současných povrchových úprav stavebně-truhlářských výrobků v exteriéru
Luňáček, Martin
This thesis compares the differences between the use of classical and contemporary treatment practices of woodwork surfaces in carpentry, focusing on wood products made of acacia, oak, and spruce. Ox blood and used automotive oil were used for classical surface treatment whereas water-soluable pigment paints were used for contemporary treatment practices; choices were based on various conditions, such as weather, wind, or cardinal directions. Changes of the surface conditions were monitored and form the basis of this thesis; experimental measurement of samples, which were exposed to exterior conditions for ten months, form the basis of research data. A set of samples which were kept under constant environmental conditions with no access to light were stored in a laboratory in order to provide a set of contrasting samples to samples exposed to exterior conditions.
Kvantifikace odchylek objemu dříví při jeho měření harvestory a rozbor jejich závislostí na vybraných faktorech
Lesák, Josef
This thesis focuses on the problems with determining the dimensions of the timber during the processing with the harvesters. This study discusses all the possible variations in measurements, their origin and a resulting impact on the volume of the timber. Furthermore, this thesis describes other methods of measuring timber, such as manual measurement or measuring by sensing proportions of the timber with a saw measuring frames. The emphasis is on the variances in the calculation formulas, particularly focused on the differences in setting the reading bark. The research is supported by two measurements in the field, more specifically on the spruce vegetation. During these field measurements we performed the cuts with harvesters on the amount of 6 trees which were subsequently transported to the sawmill for the standard electronic checks. The log performed with the harvesters were afterwards measured twice for the purposes of precise volume measuring.

National Repository of Grey Literature : 54 records found   1 - 10nextend  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.