This thesis deals with the possibility of using evapotranspiration for efficient drying of wood. An important prerequisite is that the trees with good coppice pleated capability even after they are felled and physiologically active until they have enough water in the wood. The physiological activity sheets then accelerates the drying of wood. In search of work deals with familiarization with the problems of drying biomass possibilities of its use, and other definitions associated with this work. The main output of this work is to evaluate the decrease in water content in the wood poplar Populus maximowiczii x Populus nigra 'Max 1-5', chopped down just before the start of the growing season, due to evapotranspiration. In discussing data are compared with other available literature and summarized at the end of everything.

The main content of the thesis comparing selected stands at LZ Židlochovice. Forests were compared with a predominance of English oak (Quercus robur), black walnut (Juglans nigra) and poplar stands (Populus spp.). It was not pursued only production functions, but the thesis deals with evaluation of non-production functions of forests and their social importance for the population. The results indicate that the selected forests at LZ Židlochovice have high bioproduction and sanitary-hygienic function. Conversely ecological functions - stabilization is low. In economic terms can return from the forests very high, assuming grow quality range

The aim is to compare and evaluate the production of pellets and short piece of wood to its use for heating houses. Work presents the results of measurements of energy intensity of production short piece of wood per unit volume, compared to naturally drying metods and determination of bulk density at a given humidity. There was also found mechanical resistance, moisture and bulk density of pellets of different manufactures. Conclusion contains the proposal which describes technology for heating a house with use of both types of biofuels.

The main objective of this study was to determine the effect of elevated CO2 and drought on growth of fast-growing trees, hence hybrids of poplar Populus nigra and Populus maximowiczii on experimental station Domanínek. These parameters were measured: photosynthesis, reflectance, fluorescence of chlorophyll and content of chlorophylls and flavonols. The results show a demonstrable effect of greater regulatory abilities stomatas at elevated CO2 concentration, which leads to greater efficiency of water use. Decisive influence on leaf area, specific leaf area and the dry weight has the effect of drought. However, for specific leaf area, contrary to expectations, there was an noticeable increase during drought period. In the case of other characteristics come to reduce them. By contrast specific leaf area slightly decreases at elevated CO2 concentration. Rate of photosynthesis increases with increasing concentrations of CO2, while the effect of drought dampens these characteristics and also reduces the chlorophyll content. Increasing concentration of CO2 during the experiment also leds to an increase in NDVI index, which shows increased chlorophyll content. The values of fluorescence at two concentrations of CO2 when exposed to drought stress differed minimally. The maximum quantum yield of photosystem II is slightly higher at elevated CO2 concentration. Overall, it can be summarized that in the short-term effect of drought stress in hybrid poplar, increased concentration of CO2 increases water use efficiency and thus to mitigate the impact of drought on photosynthetic parameters.

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Made available in DSpace on 2014-12-17T14:58:10Z (GMT). No. of bitstreams: 1 JoseAON_DISSERT2.pdf: 5185692 bytes, checksum: 367f032712c5c62b8f1be324410ba3fc (MD5) Previous issue date: 2011-09-12 / This work presents an optimization technique based on structural topology optimization methods, TOM, designed to solve problems of thermoelasticity 3D. The presented approach is based on the adjoint method of sensitivity analysis unified design and is intended to loosely coupled thermomechanical problems. The technique makes use of analytical expressions of sensitivities, enabling a reduction in the computational cost through the use of a coupled field adjoint equation, defined in terms the of temperature and displacement fields. The TOM used is based on the material aproach. Thus, to make the domain is composed of a continuous distribution of material, enabling the use of classical models in nonlinear programming optimization problem, the microstructure is considered as a porous medium and its constitutive equation is a function only of the homogenized relative density of the material. In this approach, the actual properties of materials with intermediate densities are penalized based on an artificial microstructure model based on the SIMP (Solid Isotropic Material with Penalty). To circumvent problems chessboard and reduce dependence on layout in relation to the final optimal initial mesh, caused by problems of numerical instability, restrictions on components of the gradient of relative densities were applied. The optimization problem is solved by applying the augmented Lagrangian method, the solution being obtained by applying the finite element method of Galerkin, the process of approximation using the finite element Tetra4. This element has the ability to interpolate both the relative density and the displacement components and temperature. As for the definition of the problem, the heat load is assumed in steady state, i.e., the effects of conduction and convection of heat does not vary with time. The mechanical load is assumed static and distributed / Este trabalho apresenta uma t?cnica de otimiza??o estrutural baseada no M?todo de Otimiza??o de Topologia, MOT, desenvolvida para solucionar problemas de termoelasticidade 3D. A abordagem apresentada fundamenta-se no m?todo adjunto unificado de an?lise de sensibilidade de projeto e destina-se a problemas termomec?nicos fracamente acoplados. A t?cnica faz uso de express?es de sensibilidades anal?ticas, possibilitando uma redu??o no custo computacional por meio da utiliza??o de uma equa??o adjunta de campo acoplado, definida sobre os campos de temperatura e deslocamento. O MOT utilizado ? baseado na abordagem material. Desta forma, para fazer com que o dom?nio seja composto de uma distribui??o cont?nua de material, possibilitando o uso dos m?todos cl?ssicos de programa??o n?o linear no problema de otimiza??o, a microestrutura ? considerada como um meio poroso e sua equa??o constitutiva homogeneizada ? fun??o apenas da densidade relativa do material. Nesta abordagem, as propriedades efetivas dos materiais com densidades intermedi?rias s?o penalizadas com base em uma microestrutura artificial fundamentada no modelo SIMP, (Solid Isotropic Material with Penalty). Para contornar problemas de tabuleiro de xadrez e reduzir a depend?ncia do leiaute ?timo final em rela??o ? malha inicial, ocasionados por problemas de instabilidade num?rica, restri??es ?s componentes do gradiente de densidades relativas foram aplicadas. O problema de otimiza??o ? resolvido aplicando-se o M?todo do Lagrangiano Aumentado, sendo a solu??o obtida atrav?s da aplica??o do M?todo dos Elementos Finitos de Galerkin, utilizando no processo de aproxima??o o elemento finito Tetra4. Este elemento tem a capacidade de interpolar tanto a densidade relativa quanto as componentes de deslocamento e temperatura. Quanto ? defini??o do problema, o carregamento t?rmico ? suposto em regime estacion?rio, isto ?, os efeitos da condu??o e da convec??o do calor n?o variam no tempo. O carregamento mec?nico ? assumido est?tico e distribu?do

This thesis deals with the cultivation of fast growing trees, mainly the Japanese poplar, as the most widespread species cultivated in our territory. The first part of the thesis describes the history of fast growing timbers, followed by presentation of individual species of poplars. Furthermore, the individual methods of cultivation technologies are analyzed, from the selection of suitable habitat to the final reclamation of the plantation. The final part of the literary review describes the non-production functions of plantations, including possible negative impacts of growing fast growing timbers. The practical part of the thesis describes a private plantation of Japanese poplar clones located in the cadastral area of Žabčice. The measurements were made on a particular plantation. From the obtained data an estimate of the future plantation yield for individual clones was performed by power regression. The final part of the thesis discusses the data obtained mainly from the economic point of view.

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The work deals with the analysis of production and economic parameters of plantation short rotation coppice LMB in LS Deblín. Production plantation was assessed after 7 and 8 years since its inception through a network of inventory plots and stencil poplar. Surveys to be wood volume (m3) and the total biomass (o.d.t). Plantation economy was measured as the difference between revenues and costs. The survey was also regenerative experiment to assess the influence of the width of the cuts on the growth of poplar saplings. Total volume production of tree plantations for 2012 was set at 46,95 +/-9,7 m3. Total volume production of tree plantations for 2013 was set at 63,41 m3 +/-10,5 m3. Total dry weight biomass for 2012 amounted to 23,31 t/ha ie 3,33 t/ha/year. The following year, the total biomass dry weight was for 8,42 t/ha greater. The average production was also greater, it reached 3,97 o.d.t/ha/year. The total cost of the plantation in the first rotation reached 79 022 CZK. The cost of timber harvesting in 2012 amounted to 7 485 CZK. The total yield of the plantation in 2012 was 72 906 CZK. The profit in 2012 amounted to -6 116 CZK . Total revenue for 2013 amounted to 99 249 CZK. The profit in 2013 amounted to 20 227 CZK. Next experiment shows vigorous sprouting capacity. Wider cuts (3 lines) is generally larger than the cuts closer (2 lines). It was also found that the wider lines is greater proportion of sprouts in the greatest height class (+2 m).

This diploma thesis describes the comparison of two different kinds of structures of snowboard wooden core. One is a combination of ash and poplar (long known and reliable structure currently used by the company Hackboards Ltd.). The other is tested combination when abele is replaced by lighter balsa wood. For both types of core the same types of fibreglass, base and top sheet are used (triaxial fibreglass, sintered base, protective top sheet). The individual mouldings were cut to the required sample on which the tests were made for the determination of bending strength according to ČSN EN 310 and impact bending according to ČSN EN ISO 179-1. Then according to ČSN EN 322 and ČSN EN 323 the moisture and density of used wooden boards were set. The measured results were evaluated and presented in charts and tables in the experimental part of this work.