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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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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 electrode for hybrid electric vehicles
Opravil, Petr ; Zimáková, Jana (referee) ; Bača, Petr (advisor)
This bachelors thesis is focusing on degradational proceses occurring in electrodes of lead-acid batteries working in parcial state of charge used in hybrid electric vehicles. Studied topics include storage of electrical energy, hybrid powertrains and lead-acid accumulators. Experimental cells have been made and were later used in experiments maintaining partial state of charge. This work is focused on finding a link between silanized glass fibres added to the electrodes and lowering the amount of degradation of cells.
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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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The influence of electrolyte additives to lead-acid batteries properties
Dohnal, Martin ; Zimáková, Jana (referee) ; Bača, Petr (advisor)
This day is a lead battery is most prevalent in the automotive industry. Which is a source of energy when starting the car. In recent times the battery is used not only for startups, but also when driving in city traffic. This behavior can know the concept of a hybrid car. Which is used an electric motor which as a result reduce emissions standing cars in cities. The electric motor is powered by lead-acid battery and a rapid discharging and reducing battery life. To extend the life developed additives to the electrolyte. In the thesis, these additives investigated. If they really have a positive effect on the battery.
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Low temperature behaviour of asphalt mixtures
Štěpanovský, Vlastimil ; Stehlík, Dušan (referee) ; Hýzl, Petr (advisor)
In this thesis it was paid attention to behaviour asphalt mixture of low temperature. The theoretical part deals with the technologies for reducing of mixing temperature and with their comparison. The thesis is notionally divided into two parts. The practical part is focused on the assessment of low temperature features by the test of asphalt mixture resistance against the formation of frost cracks according to ČSN EN 12697-46. Three mixtures were tested. The aim was to find if the low-temperature characteristics get worse compared to the commonly tested mixtures of the same gradation.
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Tribological behavior of detonation nanodiamond dispersed in lubricants
Dočekal, Martin ; Čermák, Jan (referee) ; Svoboda, Petr (advisor)
Currently tribological laboratories are looking for a new type of solid ingredients, to create a lubricating composition with minimal friction, heat resistant, with particles well dispersed in oils, sedimentation stable, improving the running properties and to minimize the concentration of solids. Nanodiamonds (DND) could exhibit the possible solution. These particles (in nanometers size) have very good physical and chemical properties, high hardness and resistance. The main advantages are effectiveness at low concentrations, compatibility with various types of oils or environmental safety (carbon additive, unlike metal) in a comparison with other types of additives. However, it is necessary to study these ingredients. The aim of research was to examine the influence of diamond nanoparticles on friction in a lubricated contact (elastohydrodynamic mode). Using tribological equipment, 3D optical profilometer and a microscope, we compared and evaluated using oil with diamond nanoparticles as well as without them. The research focused on the behavior of nanoparticles in contact and the effect they have on friction. To assess these properties of nanodiamonds, EHD optical tribometer was used (this is a device designed for the study of thin lubricating films). 3D optical profilometer and a microscope to assess the wear. And to determine the relationship between the coefficient of friction (COF) and time, Mini Traction Machine was used.
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