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Material utilization of secondary raw materials
Šolar, Matěj ; Valášek, Petr (advisor) ; Brožek, Milan (referee)
Purpose of this Bachelor thesis is to summarize actual information in area of material utilization of secondary raw materials. With focus on waste treatment from metals, plastic and glass. There are summarized technological trends in waste treatment. Also there is briefly introduced issue of waste management in the Czech republic. Material discussed in this work has their short description at the beginning of chapters: Metals, Polymers, Glass. Information about every concrete type of waste mentioned in this work is in subchapters. It is followed by concrete examples of technologies, which are currently considered as attractive. Work is replenished by images which support better understanding and imagination of issues.
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Mechanical properties of biocomposites
Janošík, Petr ; Valášek, Petr (advisor) ; Müller, Miroslav (referee)
Goal of this diploma thesis was to describe mechanical properties of epoxy resins containing organical fibers and to experimentally evaluate the effect of the fiber length with various concentrations on final mechanical property of composit material. First part of the diploma thesis is dedicated to literature review which describes general properties of fiber composites, materials which they are made of, and mechanical trials. In chapter called Methodics, materials used for experimental research are described. Process of sample preparation and mechanical trials, which were used for the test, are also described there. Last part of the diploma thesis is dedicated to evaluation of results of executed mechanical trials on composites with fiber support of various lengths and concentrations
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Inventory of woody plants in an area of 'Červený vrch' in Prague 6 and elaboration of the digital map of this selected area
Táborská, Anna ; Kunt, Miroslav (advisor) ; Prokeš, Radek (referee)
The aim of this thesis is to evaluate the current condition of flora located on the housing estate Červený Vrch in the municipal district Prague 6. The inventoried area is situated in the north-eastern part of the housing estate between the streets of Evropská st. and Horoměřická st. In this territory the woody plants have been inventoried according to Machovec (1982). The individual components of the local dendroflora have been indentified and localised in a work map or, eventually, by GPS coordinates. Based on the beforementioned localization a digital map of woody plants was created using the AutoCAD software. Furthermore the values of age and height of the local woody plants were measured and the landscaping value was determined. All the beforementioned values were imported to the inventory tables, which were created using the Microsoft Excel software and are a part of the thesis results.
In the literature search there is a short summary of the history of the garden art. Furthermore there is a chapter devoted to the historical evolution of the urban flora, the urbanism of the 20th century and the creation of housing estates in Prague. The presented thesis also contains chapters devoted to the important persons of the urbanism movement, such as Ebenezer Howard and Le Corbusier, who played a major part in the emergence of flora into the cities. The Ebenezer Howard theory of the garden city is analysed in detail. The next part of the research is dedicated to the landscape creation, its values and division. The final part is devoted to the urban greenery and its division and importance.
The sole area of Vokovice in Prague, where the Červený Vrch housing estate is located, is described in detail in the Chapter named the materials and methods. In particular, the nature characterization of landscape, the history of Vokovice housing estate and the construction of a prefab housing estate from around the time of 60s and 70s are analysed. The used methods of invetorying according to Machovec (1982) and subsequently the process of invetorying are described.
The second half of this thesis consists of the inventory tables and the visual and verbal evaluation of the beforementioned tables. From the results it is evident that the largest portion of 60% of woody plants is represented by deciduous shrubs, and hence there are plenty of their growths. This is mainly caused by the large number of seeding trees present. Thereafter the most frequently present tree species and their measured characteristics are evaluated. Finally, there is a comparison of the methods of inventorying according to Machovec and the classification of woody vegetation elements by Miloš Pejchal.
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Trends in the design and creation of new materials
Rodrová, Veronika ; Gaff, Milan (advisor) ; Borůvka, Vlastimil (referee)
The objective of my research is to examine the influence of densified wood in combination with native wood on its mechanical properties such as moduls of elasticity, bending strength, limit of proportionality, bendability coefficient and tensile-shear strength of glued line.
The examined woods are Europen beech (Fagus Sylvatica L.) and Aspen (Populus tramula L.). The tests were carried out on speciemens with different thickness. The densification by 10% and 20% was performed. For the glued joint polyurethane adhesive and polyvinylacetate glue were used.
The thesis includes simulation of the properties, their computer program tetsing, and the comparsion with the values obtained from real measurement. The purpose of this part of thesis is to achieve a simulation that will replace laboratory tests or disprove this method of scientific research and deepen our knowledge of proceses occuring during the pursued way of stress.
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Penetration of Commercial Filter Materials in Detailed Study
Ondráček, Jakub ; Zíková, Naděžda ; Ždímal, Vladimír
Testing of various filter materials proved the functionality, good precision and reproducibility of a home-made filter tester. The measurements of penetration for standard commercial filter materials might be useful for many scientists and other users working with these materials. The comparison of penetration for different types of filtration materials showed wide variety of penetration curves, MPPS and the maximum penetration. This study also confirmed our initial doubts about the standard filter efficiency testing method, regarding the used testing material, setting of MPPS and measuring only the total penetration of a polydisperse aerosol. Therefore, such a study could serve also as a basis for improvements in the filter efficiency standard method, which seems to give insufficient and in some perspectives limited or even misleading information.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22012102615351 - PDF
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Does oxidation make the organic aerosol coatings more hydrophilic? Insight from molecular dynamics study of oxidized surfactant monolayers
Roeselová, Martina ; Khabiri, Morteza ; Cwiklik, Lukasz
Organic compounds are ubiquitous in atmospheric aerosols. The morphology and structure of the organic phase affect the optical properties of the aerosols, their heterogeneous reactivity as well as their ability to nucleate cloud droplets and ice particles. It is commonly assumed that atmospheric oxidative ageing of the organic material, leading to the formation of polar groups such as carbonyl (=O), hydroxyl (-OH) and carboxylic acid (-COOH), will render the aerosol particle surfaces increasingly more hydrophilic, hence, able to take up more water. Field measurements have shown that a large fraction of the organic material found in aerosols are surface active compounds, such as fatty acids and lipids(Tervahattu, 2002 and 2005). An inverted micelle structure, with an aqueous core surrounded by an organic surfactant layer, has thus been proposed for aqueous aerosols, both marine and continental (Donaldson, 2006). While recent experiments suggest the existence of more complex structures, such as organic inclusions and surfactant lenses (Dennis-Smither, 2012), a monolayer (ML) of surface active organics on an aqueous subphase (the so called Langmuir monolayers) represents the basic model system used in laboratory studies aimed at elucidating the effect of oxidative processes on structural properties of organic coatings on aerosol particles. In our previous work, we used molecular dynamics computer simulations to study the structure and stability of oxidized phospholipid MLs (Khabiri, 2012). In this contribution, we employed the molecular dynamics simulation technique to investigate – with atomistic resolution – structural changes occuring in a fatty acid ML upon moderate degree of oxidation.
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Influence of geometric parameters on the stiffness of traditional dovetail timber joint
Kunecký, Jiří ; Cacciotti, Riccardo ; Kloiber, Michal
The paper presents the development of numerical modeling for a traditional dovetail timber joint. The objective is to find the influence of its geometrical properties on the mechanical stiffness of the joint as well as to assess the main problems and limitations faced during the numerical modeling of the structure. An experiment with a replicated timber joint was used to validate the model. Material properties were ascertained and contact adjustment was made. Parametric study was performed: two angles of the joint beams were varied. Suitable ranges of the angles for each type of loading were found. Main limitations and problems present in the modeling are depicted in the discussion.
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Evaluation of growth of beech plantations (Fagus sylvatica L.) in dependence on used reproduction material and site-ecological conditions.
Florián, Tomáš ; Remeš, Jiří (advisor) ; Bílek, Lukáš (referee)
Abstract On the Forest district Strašice, which is located at the Division Hořovice, Military Forests and Farms was founded in 2012 eight plots on 4 wooded clearings. Boots were afforested beech (Fagus sylvatica L.). Forestation was on these plots used simpleroot planting stock a indoorroot planting stock. Another criterion was the intensity of sunlight seedlings (permanent sunshine / shading; during the day changing insolation). The aim of this thesis is to evaluate the growth of seedlings depending on the planting stock and intensity of solar radiation. Subsequently, the proposed recommendations, which would be appropriate to deal with in practice. Seedlings were permanently marked with a unique letter and number. From 2012 until 2014 at the end of the growing season measured growth variables - root collar diameter, height of seedlings, height increment, quality features and mortality. Top maturing seedlings on an area where it was used in afforestation simpleroot planting stock material and irradiation area during the day alternating shading. Not permanently sunlit and shaded. On the contrary, indoorroot planting stock material is higher on permanently sunlit area than in permanently shaded. This result is identical to the results of other well-oriented work. The results and conclusions of this thesis is planted beech recommendations on areas where direct exposure varies during the day with the shading (light - shadow). However, it is not always possible and feasible, in terms of the internal structure of vegetation planted beech at said place. It is therefore possible to plant bare planting material surfaces with extreme lighting conditions (areas permanently sunlit or shaded). But what concerns simpleroot planting stock material it is advisable to observe the fact that much better grows in areas with favorable conditions (areas with alternating irradiation and shading). It is also necessary to comply with environmental requirements beech. Always determine the most appropriate place on the bare surface (Clearfelling) for the planting of beech. Use only high quality planting material conforming to CSN 482115. Professional supervision forester at cut the grass work quality and functionality over the fence, and thus mitigate damage by animals. Therefore seek the highest possible representation of planted trees (to comply with the statutory requirements for supportability) due to the selection of the best individuals in the education and creating the future quality and healthy growth.
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Activity of CoMo/MSA Catalysts in Benzothiophene Hydrodesulfurization, Cumene Cracking and Cyclohexene Isomerization
Gulková, Daniela ; Kaluža, Luděk ; Zdražil, Miroslav ; Vít, Zdeněk
It was found that MoO3 does not adsorb onto pure SiO2 despite its relatively high surface area (400 m2/g). In contrast, SA52, MSA30, and MSA19 with surface areas 430, 580 and 600 m2/g adsorbed about 14, 7 and 3 wt. % of MoO3, respectively. The content of Al2O3 in the SA based materials thus well correlated with the adsorption loadings of MoO3 achieved by the saturation experiments. Moreover, it was acquired that the highest dispersion and HDS activities were achieved over catalysts containing dealuminated MSA supports despite of relatively low loadings of Mo. After Co deposition, the weight normalized activities in BT HDS increased 2.2 and 4.3 times on effective MoS2 promotion by Co on more acidic supports. Furthermore, those catalysts keep the high acidities of the original supports, as it was determined by cyclohexene isomerization and cumene cracking, while industrial reference CoMo catalysts supported onto gamma-Al2O3 was found to exhibit low acidity.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22012102413541 - PDF
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