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The thesis is focused on the problems of degradation of engine oils of the same viscosity class 5W-30.The first part of the thesis is describing lubricating systems and their component parts. The thesis also focuses on the division of oil in each classification and description of its properties. Samples of the oil have been taken from two cars with identical diesel engine, but with different total traveling distance. Attention is paid to the amount of structural metals, contaminants and additives in both oils, and throughout the oil usage interval. The results are interpreted graphically and various dependencies are modeled using appropriate regression functions. Thesis compares the mechanical and physical properties of engine oils, depending on mileage. The conclusion summarizes the evaluation and the results obtained.

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

This doctoral thesis is concerned with particles in modern Vietnamese. Although Vietnamese particles form a small group of synsemantic words, they play a very important role in expressing the attitude of the speaker to the hearer/listener and to the message content as well as expressing grammatical and modal relationships within the sentence. The group includes particles positioned at the end of the sentence, particles appearing before a word as well as at the beginning of a phrase or a sentence. Despite their important function, particles in Vietnamese still are a scarcely explored topic. Particles have been explored usually as part of grammar books; so far, there are only few monographs on the topic of particles. Almost all works deal with a small number of particles and focus especially on those appearing at the end of the sentence. This work is concerned with particles at the end of the sentence as well as particles preceding a word, a phrase, or a sentence. It examines whether particles in Vietnamese are a part of speech at all; it sets forth criteria for classification of particles; it performs their analysis based on actual situations where they appear and describes their semantic characteristics; furthermore, it offers a chart of particles including their possible combinations. Besides, the...

This thesis deals with really small cyclone separators which could be used for a flue gas purification. The search section discusses particle formation in combustion, their characteristics, any other flue gas cleaning options and last but not least, a cyclone separator where is the effort to understand all the influences that contribute to a cyclone’s resulting separability. The Experimental section analyses a calculation of the cyclone and theoretical separability, a verification of this separability using a cyclone created by a 3D printer. On the one hand, the verification was made by gravimetric analysis which is intended for a bigger particles, on the second hand, it was made using the PALAS which is aimed at particles in µm. There is also a comparison of theoretical and measured values in this section.

Wind erosion is one of the mail reasons of soil degradation. The amount of wind erodible fraction (EF) is the key parameter regarding wind erosion susceptibility of the soils. As the EF of the soil is considered percentage of aggregates < 0, 84 mm in diameter. Dry sieving with use of rotator or flat sieves is the standard method for EF estimation The main aim of this study is comparison of standardized flat sieving method against the use of equations for predicting EF. The first of these equations, EF = 29,09 + (0,31.sand) + (0,17.silt) + (0,33.sand/clay) - (2,59.ogranic matter) – (0,95.CaCO3), was proposed by D. W. Fryrear in 1994. But it has not been tested outside of USA, Spain and Argentina, so far. Another equations used here, EF = 9,98 + 6,91.(sand/clay) + (14,1/organic matter) a EF = 4,77 + 7,43 (sand/clay) + (27,6/ organic matter), were proposed by M. V. López in 2007 during his research of EF. The results show that the values obtained by calculating these equations do not match the EF obtained by means of a flat sieving. With the use of the statistical program Unistat the new equations have been proposed, EF = 84,94 - (0,03.sand) - (1,36.clay) + (1,90.Corg) + (43,14.CaCO3), EF = 84,77 - (0,02.sand) - (1,34.clay) + (0,95.humus) + (42,71.CaCO3) and EF = 21,25 + (0,52.silt) + (7,63.sand/clay) + (0,41.humus) – (7,44.CaCO3), for the determination of EF in the surveyed soil samples.

The thesis deals with meshfree methods, especially the SPH method. It is focused on the question of convergence near the boundary of the problem domain and its following solution in the form of using the so-called ghost particles as a boundary condition. There is also presented a suitable setting of parameters for a shock tube 2D problem based on many tests and software modifications.

MicroRNAs are small non-coding RNA molecules with length of about 22 nt. These molecules participate on regulation of gene expression at the post-transcriptional level. They represent the largest group of regulators in the cell and therefore are also involved in all key processes such as proliferation, differentiation or apoptosis. Moreover, they participate in tumor transformation. These small molecules have a great potential to be diagnostic markers or assist in the treatment and prevention of diseases. This research was focused on the development of isolation method using magnetic particles with subsequent electrochemical detection of microRNA. Optimization steps were performed and then the entire method was successfully applied to real samples of HEK293 cells expressing increased levels of miR-124. The developed method proved to be sufficiently specific and applicable to the analysis of microRNA.

Thanks to the prove of connection between the aberrant occurrence of small RNA and various diseases and their potential in diagnostics and treatment led to discovery of new methods and materials facilitating their detection and targeted transport during gene therapy. This work summarizes present knowledge about chosen groups of small RNA, their significance in medical science and the possibilities of their detection. This work primarily concentrates on combination of magnetic separation with electrochemical detection. Magnetic particles (MPs) with different surface modifications were used for isolation. Non-specific isolation was carried out using silanol-coated MPs; streptavidin-coated MPs modified with specific biotinylated probe were used for specific separation. Square wave voltammetry (SWV) was used as a very sensitive electrochemical detection method. Optimized method based on specific magnetic separation with SWV was able to reach nanomolar detection limit (4 nM) with microRNA. The method was applied on human embryonic cells for specific isolation and detection of miR-124. The CdTe quantum dots (QDs) were studied as a nanomaterial tool for nucleic acid detection. The QDs were modified with streptavidin for their bioconjugation with biotinylated molecules were used. Interaction of QDs with nucleic acids was studied using capillary electrophoresis.