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Difuzní vlastnosti OSB desek v důsledku zasažení nadměrnou vlhkostí.
Žižková, Lucie ; Vertal', Marián (referee) ; Chybík, Josef (referee) ; Bečkovský, David (advisor)
The presented dissertation focuses on the change of diffusion properties in oriented strand board (OSB) panels after exposure to excessive moisture. OSB panels undergo a change in their diffusion properties after being affected by excessive moisture and subsequently dried, causing them to deviate from the original design of the wooden wall structure. The aim of this study is to describe the experimentally measured change in diffusion properties and incorporate it into the composition of a real wooden wall structure, evaluating its performance through computer simulation. The introduction of the dissertation provides the theoretical basis for the experimental section, which includes measurements of water absorption, diffusion properties, and the risk of mold growth. The experimental section describes the approaches and methods used to achieve the objectives of the dissertation. The measurements were conducted on test samples of OSB panels in the laboratories of the Institute of Civil Engineering. After being exposed to excessive moisture, the test samples were dried using two drying methods. The dried test samples were placed in testing assemblies, where diffusion was measured using the dry cup method. The measurements were carried out in two stages, with more than 80 samples measured in each research stage. In the final part, the measurements are evaluated through graphs. The change in diffusion properties was then incorporated into the composition of a real wooden wall structure and assessed using computer simulation, which is more commonly used in practice according to ČSN 73 0540 (Czech Technical Standard).
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Possibility of using EMW radiation for killing biotic pests
Gintar, Jan ; Klečka,, Tomáš (referee) ; Pěnčík, Jan (referee) ; Šuhajda, Karel (advisor)
The remediation of building elements and structures in terms of moisture and sterilization (inactivation) of biotic pests is dealt with quite often in construction practice and in the construction industry itself, and is thus a topical issue. The issue is dealt with by specialized companies that know the use of available technology on the market, or are themselves involved in the development and improvement of these devices. Several methods are known for the removal of moisture and sterilization of biotic pests, with sufficiently high-quality data on the technology used, the suitability of the equipment used, a more detailed description of the application of the methods themselves and the results themselves. The methods themselves, for removing moisture and eliminating (inactivating) biotic pests, must be chosen according to individual requirements, as some methods will be more appropriate (more effective) and some less suitable. For the practice itself, however, it is important that the methods are sufficiently effective and at the same time available to the wider public (their economic side). In my dissertation thesis I focus on the potential of EMW radiation utilization not only for liquidation of biotic pests (fungi, fungi, wood decaying insects), but also elimination or reduction of necessary conditions for survival or development of these biotic pests. Therefore, my work also focuses on the presence of moisture, because moisture is a common factor in the vast majority of problems associated with the occurrence of biotic pests. Due to its intensity, it is one of the less time-consuming method and therefore a more cost-effective (economically) method. The research I conducted at VUT FAST focused on the use of microwave radiation in the control of biotic pests, under conditions that are close to those on real constructions. The use of a microwave method to eliminate biotic pests and at the same time to remove moisture has proved to be advantageous.
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Separation of water drops from jet of steam
Miček, Michal ; Baláš, Marek (referee) ; Pospíšil, Jiří (advisor)
This thesis is focused on separation water drops from jet of steam. Liested are some of basic principles of separation of moisture and particles, as well as equipment, which are using these principles. Furthemore, this thesis include the part devoted to water drop formation during condesation of vapor. Last part is focused on the design of cyclone separator.
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Damage extent analysis of dry floors in case of a flood
Šír, Jan ; Vlach, František (referee) ; Bečkovský, David (advisor)
The thesis is focused on analysis of damage extent of dry floors in case of a flood. In the first part it deals with problems of buildings´ stress factors in the point of view of building physics, floor composition and its connection to constructions of timber houses. In the second part it describes testing of three experimental floor samples during simulated flood. It examines and evaluates the behavior and the way of spreading of the leaking water and the effect of moisture on the materials.
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Hygrothermal response of building components
Slávik, Richard ; Šťastník, Stanislav (referee) ; Vertál´,, Marián (referee) ; Kalousek, Miloš (advisor)
This dissertation thesis is focused on the study of simultaneous transport of heat and moisture in building components. First, the introduction briefly summarises current international state of the art in assessment and evaluation of building components focused on moisture. Besides description of methodological approaches and analysis of differences between them, the approaches are modelled using examples which help to identify their properties and explain the application framework of the methods. These examples do not only illustrate the procedures; they also indicate their limits and identify the pitfalls of models’ application in comparison with each other. Next, the thesis includes basic introduction to material parameters necessary in numerical modelling. Moreover, solutions to questions from the assignment are discussed from the point of view of the theory of heat and moisture transport. To fulfil the thesis’ objectives, theoretical analysis and calculations were implemented. Calculations were carried out not only by well-known methods, but also using an own-developed complex algorithm which implements simultaneous heat and moisture transport modelling based on finite element methods and which allows to implement nonlinear behaviour of material properties. Furthermore, the thesis contains description of and results from two experiments. A brief description of an electronic device developed and used for the experiments is included. Experimental results are confronted with both simplified and advanced theoretical models. At last the thesis concludes with discussion of acquired findings, brief summary of potential contribution of this work to the field of building science and engineering practice, and indication of the directions for further development.
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Disposal of Biotic Pests by EMW Radiation
Sobotka, Jindřich ; Klečka,, Tomáš (referee) ; Myslín, Jiří (referee) ; Tomíček,, Oldřich (referee) ; Šuhajda, Karel (advisor)
The possibility of using high-frequency electromagnetic radiation in the construction sector is a common knowledge. Various experiments have been carried out to dry construction materials, or even to destroy biotic pests. However, the majority of these experiments have been executed in laboratory conditions. It means they have been carried out under exact limiting conditions, often very far off those conditions in real building practice. Therefore, this dissertation aims at exploring the possibility of utilizing microwave technology in drying and heating of construction materials, in disposing of biotic pests and sterilizing building materials under real conditions in building practice. The thesis will explain that microwaves are a term given to a part of electromagnetic radiation. Electromagnetic radiation is based on the principle that the radiated energy is absorbed by water molecules present in moist building material. In the mass of the irradiated material, the radiated energy is transformed into thermal energy, where a so-called “motion” of water molecules occurs with the energy then being transformed into kinetic energy. The microwave technology itself offers a very wide range of use, which can be easily achieved, thus making the technology available to use in the future. Part of the experiments and the necessary measurements, too, has been carried out on selected types of building materials in the premises of the Faculty of Civil Engineering of Brno University of Technology. They have been executed under conditions which most closely correspond to the conditions in real buildings. Part of the experiments and the necessary measurements were carried out on particular constructions, by the so-called in situ method. As stated in the conclusion of the dissertation, laboratory measurements and the in situ measurements differ considerably in some cases.
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Moisture Measurements
Hřib, Jan ; Pikula, Stanislav (referee) ; Beneš, Petr (advisor)
This bachelor’s thesis deals with measuring moisture in building materials and it is focused on the capacitive and microwave method. The goal was to find out whether it is possible to employ these two methods to determine moisture distribution in the volume of a measured material. This thesis contains theoretical introduction to the moisture measurement. Practical experiments were made with both capacitive and microwave method. Capacitive method was supplemented with a simulation. Based on the results, I conclude that the capacitive method is not suitable to determine moisture distribution in the volume of a material. The same conclusion was reached in the case of the microwave method, although this conclusion was based more on the theory than on the measurements.
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Impact of injection on mechanical and physical characteristics of mortar
Fridrich, Pavel ; Myslín, Jiří (referee) ; Tomíček,, Oldřich (referee) ; Klečka,, Tomáš (referee) ; Tuza, Karel (advisor)
The increased moisture of the building materials causes the change of its mechanical and physical characteristic. In particular the high amount of loose water in construction shorten the lifetime of the building, is harmful to human beings due to biotic factors and increase the economic expenses of usage of the building. Apart from the costs of rehabilitation the loose water deteriorates the thermal insulative ability (thermal conductivity coefficient ) of perimeter masonry as well. The moisture gets into masonry not only through its deffects but also due to many different reasons. In order to improve the utility value of the buildings we have to deal with the rehabilitation of damp masonry with view to all possible causes. Only the properly working damp proofing ensures the protection against the water leaking from the subfoundation of the building. One of the direct techniques which have undergone rapid progress in last few years is the injection procedure. With use of experimental methods in my dissertation I deal with evaluation of two injection compounds used in Czech Republic and with its impact on the characteristics of the mortar. With the modern hollow bricks (system THERM) it is possible to create horizontal infusion into the lateral mortar grooves in future.
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Re-design of biomass boiler for very wet fuel
Zbořil, Martin ; Skála, Zdeněk (referee) ; Lisý, Martin (advisor)
The aim of this thesis is to calculate the stoichiometric balance of boilers and boiler fuel for normal monture to 60%. Determine the monture, content depending on the conditions of the fuel in the combustion chamber and conditions of combustion. Experimental analysis of the current state of the boiler ZKG measurements using this device and propose modifications and solutions.
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