|
|
Influence of sand size of core mixtures on surface quality of cast iron castings
Brůža, František ; Krutiš, Vladimír (referee) ; Záděra, Antonín (advisor)
The diploma project deals with the mechanisms of burn-on casting defects on castings made of spheroidal graphite cast iron. It discusses the elimination of their occurrence in the conditions of the German foundry MAT Ueckermünde by changing the granulometry of the core sand. Subsequently, the thesis deals with the influence of this change on the greensand. Furthermore, the thesis compares three refractory coatings supplied by the foundry. The coatings are compared both by laboratory measurements and by experimental tests during casting in conditions simulating the operation of this foundry. Finally, the individual tests are evaluated, including the effect of the individual measures in the case of their use in MAT Ueckermünde.
|
|
|
Study on dependency of the weld geometry on process parametres in laser hybrid welding of austenitic stainless steel
Jireš, Daniel ; Daněk, Ladislav (referee) ; Mrňa, Libor (advisor)
The project has been solved during the bachelor´s degree of engineering technology examines the the influence of laser hybrid welding austenitic stainless steel ČSN 17240 (DIN 1.4301). This steel is the most widely used type of stainless steel, recommended for use in aggressive environments such as a swimming pools, laboratories or facilities in contact with sea water. The test specimens, which were performed on the weld bead at different speeds and other welding parameters, were metallographicly investigated. The results showed that the highest geometric parameters such as depth and width of the weld pool have the samples with welding speed v = 10 mm s-1, the smallest geometrical parameters have the samples with the welding speed v = 30 mm s-1.
|
|
|
Influence of the temperature on the preparing of asphalt mixtures with higher amount of RAP
Škrobáček, Petr ; Koudelka, Tomáš (referee) ; Varaus, Michal (advisor)
This bachelor thesis is focused on the preparation of the reclaimed asphalt pavement for production of asphalt mixtures. In the thesis there is investigated the effect of the temperature of preparation the reclaimed asphalt pavement on the characteristic of the bitumen content. In the theoretical part there is described bitumen as such and reclaimed asphalt pavement. In the practical part there is described the preparation of the material for laboratory tests. The next step is the extraction and distillation of bitumen. These bitumens are tested according to depredescribed tests: ‘Determination of needle penetration (ČSN EN 1426)’, ‘The softening point (ČSN EN 1427)’ and ‘Dynamic shear rheometer’. In the last section of this bachelor thesis there is a comparison of the individual properties of the rendered bitumen of the asphalt mixtures of reclaimed asphalt pavement, with the aim of evaluating temperatures of preheating and degradation of the bitumen on the final characteristic of the asphalt mixtures witch higher quantity reclaimed asphalt pavement. The measured values of the temperature for preparation of reclaimed asphalt pavement shows that the temperature of the asphalt mixture before production has a significant effect on the characteristics of the bitumen, which is included in the reclaimed asphalt pavement. There is evident the difference between specimen of the asphalt mixture of reclaimed asphalt pavement and the reclaimed asphalt pavement. It is visible only from the bottom layer too.
|
|
|
Penetration of metal into green sand during pouring of iron castings
Ptáček, Tomáš ; Neudert, Alois (referee) ; Záděra, Antonín (advisor)
This diploma thesis deals with the creation of penetration of cast iron with graphite casting cast into bentonite molds. In the first part of the thesis is theoretically described the formation of penetration, its main causes, consequences and the elimination of this defect. The second part analyzes the causes of the defect with the Minitab statistical software and shows the possible connections of the input materials to the occurrence of the defect. Next, the experimental finding of the cause of the defect, which is focused on the measurement of the pressures in the form of the casting, is devoted to it.
|
|
|
Optimalization of experimental method for study on penetration of humic acids into leaves.
Smilková, Marcela ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This bachelor’s thesis is focused on the study of penetration of humic substances trough the plant cuticle. The main objective of the thesis aimed at a literature search on foliar fertilization and transport of substances in the plant leaves. According to the literature search, experimental technique was suggested and tested in order to study penetration of humic substances through the leaf cuticle. The method consists of observation of diffusion transport of humic acids between two inert agarose gels separated by the plant cuticle. Cuticles were prepared by the means of three different isolation procedures.
|
|
|
Technology of manufacture and treatment of medieval arrowhead
Kašpar, Jan ; Stránský, Karel (referee) ; Stránský, Karel (referee) ; Doležal, Pavel (advisor)
This thesis analyses issue of manufacture, typology and use of medieval arrowheads. In theoretical part describe historical evolution of bow and his archaeological discovery in Europe, especially from medieval times. After that is revealed historical evolution of arrowheads and describe their typology. In next chapters are mentioned ways of iron production, mainly in early medieval times and also describe technology of manufacture different types of arrowheads. There is a characterization of medieval arrow, his construction and characteristics. Continuously in this background research are revealing questions of penetration depend on the various types of arrowheads, which are testing on the most known types of armour like chainmail or breast plate. In experimental part of this paper are metallographicaly analyzing archaeological discoveries from the early and late medieval times. Conclusions about their manufacturing, treatment and possibilities of use are built on knowledge about arrowheads structures, hardness and shapes.
|
|
| |
|
| |
|
|
Interaction between liquid metal and foundry mixture
Tomek, Ladislav ; Muselík, Pavel (referee) ; Rusín, Karel (advisor)
Subject of the diploma thesis was to resolve influence of grey cast iron on penetration into cement sand. Methodology of trial was designed and its attestation was implemented in experimental and running conditions. On boundary-line cement sand and pouring metal was certified generation of complex allied substances. Created mathematical model of mechanical penetration proved influence of temperature and chemical composition of grey cast iron on range of penetration.
|
|
|
Ageing of asphalt binders and mixtures
Štěpanovský, Vlastimil ; Komenda, Radek (referee) ; Hýzl, Petr (advisor)
Diploma thesis is particularly focused on ageing of asphalt mixtures and asphalt binders. In the theoretical part an array of methods simulating short term and long term ageing consequently is introduced. The main objective of the practical part was to carry out the long-term ageing test method BSA (Braunschweiger Alterung). Thereafter, specimens testing for stiffness properties according to CSN EN 12697-26 were made. After conducting the measurement on those, asphalt binder was extracted and processed to follow-up testing. The testing consisted of a range of methods – Penetration CSN EN 1426, Ring and Ball test CSN EN 1427, Determination of the Frass breaking point CSN EN 12593, Determination of complex shear modulus CSN EN 14770 and Dynamic viscosity using a dynamic shear rheometer (DSR). The given results were assessed in the last part in order to evaluate the rate of the binder degradation caused by the method BSA.
|
guest ::
