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Lubricants in Up-to-date Combustion Engines
Čech, Martin ; Svída, David (referee) ; Dundálek, Radim (advisor)
In my bachelor work I have tried to analyze informations about lubricants in up to date combustion engines. This work deals with motor oils and their viscosity and performance classification The special motor oils for motorcycles are part of this bachelor work too. One of the aims of bachelor work provide informations about gear oils for automatic as well as manual transmissions and their classification. This work describes also questions about additives.
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Preprocessing of sewage sludge for pyrolysis process
Ševčík, Jan ; Rusník,, Igor (referee) ; Bodík,, Igor (referee) ; Hlavínek, Petr (advisor)
The concept of sludge management at the level of sludge treating technology of sewage treatment plants, as well as at national, continental or world level, requires fundamental improvement in the interest of sustainable development. Sewage sludge production is continuously increasing. Sewage sludge contains a number of pollutants but also a significant renewable resource for material transformation and / or energy recovery. Sewage sludge is composed of an inorganic mineral part and organic components. Its organic part is a source of energy and nutrients, but also contains harmful pollutants for exapmple heavy metals. However, there are technologies that offer the possibility of neutralizing pollutants while using other sludge components in terms of recycling energy, nutrients and other attractive sludge components. The mentioned technologies include mainly thermal methods of sewage sludge treatment and one of them is pyrolysis. Thessis focuses on sewage sludge prepartation for pyrolysis process, which includes mixing with additives and peletization of prepared mixture for purposes of agricultural or energetical utilisation. Technology for material transformation and energy utilization of sewage sludge, in particular the mentioned pyrolysis or torrefaction, require an insignificant degree of detailed research in order to expand it in the field of sludge management. Indeed, it is not only research that will enable direct correct use of this technology in practice. The results of such research are the basis for the drafting of the relevant legislation, which will subsequently enable the deployment of pyrolysis technologies in practice.
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Technology of waste polylactide recyclation for 3D print
Kecíková, Alžbeta ; Tocháček, Jiří (referee) ; Přikryl, Radek (advisor)
This bachelor thesis deals with the recycling of waste polylactide from the production process and its subsequent use in 3D printing. To optimize the recycling process of polylactic acid, it was recycled with the addition of various additives such as poly(3-hydroxybutyrate), talc, limestone and chain extenders Joncryl 4368-CS and Raschig Stabilizer 9000. These materials were also investigated with the addition of the acetyl tributyl citrate plasticizer. Samples of the mixtures were prepared on a twin-screw extruder and subsequently a filament was obtained using a single-screw extruder, which was then used for 3D printing by fused deposition modelling (FDM) technology. Temperature towers were printed to obtain optimal processing temperatures for 3D printing. The effect of the additives on the characteristic temperatures and the degree of crystallinity of the PLA was determined by differential scanning calorimetry. The effect of the processing on the molecular chain of selected samples was observed by gel permeation chromatography. Furthermore, in the experimental part of the bachelor thesis, the influence of additives on mechanical properties such as modulus of elasticity, tensile strength and elongation was investigated. The molecular weight was increased due to the chain extenders. Of the particle fillers for the PLA matrix, talc had better mechanical properties than limestone. The greatest effect of the plasticizer was in a mixture with poly(3-hydroxybutyrate).
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Effect of Organic Additives on Electrochemical Processes Influencing Zn-Air Battery parameters
Smejkal, Jan ; Čech, Ondřej (referee) ; Chladil, Ladislav (advisor)
The diploma thesis is focused on the study of the influence of selected organic additives on the properties and morphology of zinc deposit on the negative electrode when used in zinc-air accumulators. Organic additives have been selected based on the study of literature and previously done experiments. The deposition was made on the tin plate electrodes in a solution of 6 mol/l KOH saturated with ZnO with added additives. All chosen additives were studied with a focus on the morphology of zinc deposit and with regard to their ability to suppress dendritic growth. Zinc morphology was studied by using a Tescan Vega 3 electron microscope and a Rigaku MiniFlex HR 600 X-ray diffractometer.
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Influence of conductive ceramics on the life of lead acid batteries
Tobolák, Jakub ; Vaněk, Jiří (referee) ; Bača, Petr (advisor)
This thesis is focused on lead-acid batteries used in hybrid electric vehicles. These cells work in specific conditions, particularly under partial charge referred to as PSOC. This fact is responsible for the premature loss of capacity cell lead-acid batteries and their short lifetime. The task of this thesis is to examine the effect of conductive ceramics as possible additives to the negative electrode active materials of lead-acid battery cells operating in a PSOC, in order to prolong their life.
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Negative lead-acid battery electrode for hybrid electric vehicles
Dvořáček, Daniel ; Křivík, Petr (referee) ; Bača, Petr (advisor)
The thesis briefly discusses the issue of electrochemical power sources, especially with a focus on lead-acid batteries operating in modes that are typical of hybrid electric vehicles. The theoretical part of the thesis should be a good basis for the subsequent practical part, in which several experimental electrodes and their parameters will be performed and evaluated. The output of the practical part will be conclusions regarding the influence of different variants of modified carbon used as an additive in the active material of the negative electrode on the capacity and life of cells
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The effect of the shrinkage reducing additives on rheological properties of high-strength concrete
Červenka, Jiří ; Kucharczyková, Barbara (referee) ; Daněk, Petr (advisor)
Master’s thesis examines the effect of the shrinkage reducing additives on rheological properties of high-strength concrete. The first part is focused on high-strength concrete in terms of their composition and properties. The second part contains a detailed analysis of the cementitious composites shrinkage problems. Total shrinkage is divided into individual elementary shrinkages. For each of them there is a detailed description of causes and factors that affect their sizes. The next part describes the basic additives used to reduce the shrinkage of cementitious composites. The experimental part is focused on verifying the effectiveness of the shrinkage reducing additives during preparation of high-strength concrete. Usage of shrinkage drains for relative strain measurement enables to determine the process of shrinkage immediately after placing the concrete in the form and to obtain the overall curve of the hight-strength concrete volume changes during its setting and hardening. At the end of the thesis, there are overall analysis and summary of the results of the performed experiments.
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The verification of durability of surface layer by pull-off testing
Fujačková, Hedvika ; Komárková, Tereza (referee) ; Kocáb, Dalibor (advisor)
The theoretical part of this bachelor's thesis defines the basic properties, categorization, and use of the individual components of concrete and presents the properties of fresh and hardened concrete, especially the tensile strength. Furthermore, the thesis addresses the problem of durability assessment of concrete, which depends directly on the quality of the surface layer. The experimental part of the thesis focuses on executing of a pull-off test and examines the surface layer tensile strengths of various concrete mix designs. The thesis examines how the results of the measurements correspond with other published results.
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Microscopic Observations of Active Mass Structures of the Negative Electrode of a Lead-Acid Battery
Zimáková, Jana ; Dostál, Zdeněk (referee) ; Kohout,, Jan (referee) ; Bača, Petr (advisor)
This doctoral dissertation deals with the study of the effect of additives on the properties of the negative electrode of a lead-acid battery. The work focuses on the investigation of the additive/base material interface for the negative electrode (so-called active mass) using atomic force microscopy (AFM). A lead sheet was used as the base material, on which the given additive was applied. The effects of carbon, TiO2, glass fibers and Indulin AT were specifically investigated. The negative electrode was cycled by a potentiostat in a defined manner and the morphology of the electrode surface was continuously scanned by AFM. This created a time sequence of images on which events on the surface of the electrode during its charging/discharging were captured. These records serve to better understand the effect of additives on the resulting properties of constructed lead-acid cells, specifically on the ability to form or dissolve PbSO4 crystals, which are formed during cell discharge and are responsible for the decrease in total capacity - gradual surface sulfation.
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