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Design of a technology and checking the production of small steel ingots
Jakubčíková, Lucie ; Čamek, Libor (referee) ; Záděra, Antonín (advisor)
The thesis deals with the design of ingots from duplex (austenitic-ferritic) stainless steels in terms of minimal occurrence of axial porosity. The optimal shape and dimension of the ingot and the casting conditions are determined based on numerical simulations. The resulting internal quality of the realized ingot is evaluated. The presence of shrinkage porosity is determined by penetrant testing. The degree of chemical heterogeneity, the extent of macrosegregation, of selected elements in given ingot locations is measured by an optical emission spectrometer. Segregation values are compared with simulation results. The micro-purity of the ingot is assessed on the basis of metallographic samples.
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Recycling of asphalt mixtures - variability of RAP - parameters
Tuháček, Martin ; Koudelka, Tomáš (referee) ; Varaus, Michal (advisor)
The bachelor thesis is focused on RAP material (Reclaimed asphalt pavement), particularly on its characteristics and usage while producing hot mix asphalt at plant. The theoretical part thoroughly describes different fields of application of RAP, these include both the hot and cold recycling. The practical part, on the other hand, essentially covers the problem of using the maximum feasible amount of RAP in hot mix asphalt mixtures; mechanical and psychical properties of a binder and aggregate grading curves are evaluated. On the basis of the testing results, the classification of RAP is undertaken. Moreover, the variability of RAP characteristics is assessed and compared within two various plants. Therefore, the maximum amount of RAP added is based on the very deviation of each characteristic. Representative samples were of two sizes – 0/11 and 0/22.
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Evaluating the quality of implementation of the hand shotcrete
Kopecký, Lukáš ; Schmid, Pavel (referee) ; Svoboda,, Pavel (referee) ; Dočkal, Karel (advisor)
Currently, the high speed and low price are required for construction works in the modern architecture. Therefore, it is necessary to deal with verifying the quality of the constructions. Dissertation thesis is focused on evaluating the quality of the execution of sprayed concrete without accelerating additives applied by spraying by a dry way manually-sprayed. The quality of shotcrete was judged on the basis of standardized both non-destructive and destructive methods using sprayed samples. The quality of shotcrete was assessed in terms of strength of sprayed concrete in pressure, density and homogeneity judged on the basis of the velocity of sound samples. The destructive method was carried out on the core samples which were pressured on the hydraulic press, as the non-destructive method was used ultrasonic passageway method based on the propagation velocity of the ultrasonic pulse. On the basis of our results and their mutual correlations, it has been proposed the modifications of the general equal used for predicting the strength of the sprayed concrete tested by our strength class, which leads to a potential reduction in the number of cores on the real structure, and therefore reduce the price of implementation of qualitative tests and increase effectiveness of carrying out tests on the construction place.
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The Processing of Climatologic Records from Experimental Locations in Kyrgyzstan and the Synoptic-climatologic Interpretation Thereof
Sýkorová, Petra ; Huth, Radan (advisor) ; Pokorná, Lucie (referee)
The Charles University Faculty of Science KFGG team took part in an intensive research in the area of Kyrgyz glacial lakes. The collecting of records from three meteorological stations in the locations of Kolor (2,700 m above sea level) and Adygine (3,500 and 3,800 meters above sea level) was part of the research. The aim of this thesis was to analyze the homogeneity of climatic data measured in experimental locations using the SNHT method (Standard Normal Homogeneity Test), process the data using general climatological processes, create a classification of circulation types for the area of interest using Jenkinson's and Collinson's method, and finally, to quantify the relationships between individual circulation types and the values of chosen climatic elements. The analysis results are homogenized climatic sets for the Adygine H station (3,800 m above sea level) and a summary of basic statistics and trends of climatic elements in the area. Furthermore, a catalogue of circulation types was created for the period from August 2007 to July 2011, and finally, the relationships between individual circulation types and manifestations of climate elements (air temperature, precipitation and global radiation). The results of this thesis may be used to identify the types connected with bursts of glacial...
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Design of a technology and checking the production of small steel ingots
Jakubčíková, Lucie ; Čamek, Libor (referee) ; Záděra, Antonín (advisor)
The thesis deals with the design of ingots from duplex (austenitic-ferritic) stainless steels in terms of minimal occurrence of axial porosity. The optimal shape and dimension of the ingot and the casting conditions are determined based on numerical simulations. The resulting internal quality of the realized ingot is evaluated. The presence of shrinkage porosity is determined by penetrant testing. The degree of chemical heterogeneity, the extent of macrosegregation, of selected elements in given ingot locations is measured by an optical emission spectrometer. Segregation values are compared with simulation results. The micro-purity of the ingot is assessed on the basis of metallographic samples.
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Runoff development in selected catchments in the Kyrgyz Range, Tian-Shan
Jedličková, Šárka ; Šobr, Miroslav (advisor) ; Janský, Bohumír (referee)
The main objective of this paper was to investigate runoff changes in the catchment Ala-Arca, Alamaedin and Kara-Balta in Kyrgyzstan, as well as change in climate conditions from available stations in the area. The runoff, precipitation, and temperature series were subjected to monthly, seasonal and annual analyses based on available data. Both absolute and relative data homogeneity were verified using statistical tests such as the Mann-Whitney-Pettit test, the SNHT test, and the WiIlcoxon's two- sample test for absolute homogeneity, and the Alexandersson's test for relative homogeneity. The Mann-Kendall test was used to determine the trend in each serie. There were inhomogeneities found in a number of runoff data. In most cases, the changes of rivers Ala-Arca and Kara-Balta were recorded in 1987. Compare to Ala-Arca and Kara-Balta, the changes of river Alamedin were recorded 3 years later, in 1990. There was a positive trend development by the rivers with the glacial-snow regime. However, there was no statistically significant trend for the entire time series. Key words: runoff change, precipitation, temperature, glacial-snow regime, snow-glacial regime, homogenization, Mann-Whitney-Pettit test, trend, Mann-Kendall test, glaciation, Kyrgyzstan, Tien- Shan
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Homogenization of powder blends using a high-speed mixer
Perďochová, Kristína ; Šklubalová, Zdeňka (advisor) ; Mužíková, Jitka (referee)
Charles University, Faculty of Pharmacy in Hradci Králové Department of: Department of Pharmaceutical Technology Supervisor: doc. PharmDr. Zdeňka Šklubalová, Ph.D. Consultant: PharmDr. Karel Palát, CSc. Student: Kristína Perďochová Title of Thesis: Homogenization of powder blends using a high-speed mixer This work focuses on using a high-speed mixer for the powder mixing process in pharmaceutical technology. Shortened experimental plan was used to study the influence of three factors (mixing speed, mixing time and weight of the mixture) in order to achieve the overall homogenity of the mixture containing acetylsalicylic acid and microcrystalline cellulose. Individual samples were compressed into tablets. The homogenity of the mixture was evaluated using near infrared spectroscopy (NIR). The standard devations of the measured spectra were observed. The best results obtained from studied mixtures were achieved by a combination of mixing 150 g of mixture, rotational speed of 900 rpm and mixing time of 30 seconds.
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Evaluating the quality of implementation of the hand shotcrete
Kopecký, Lukáš ; Schmid, Pavel (referee) ; Svoboda,, Pavel (referee) ; Dočkal, Karel (advisor)
Currently, the high speed and low price are required for construction works in the modern architecture. Therefore, it is necessary to deal with verifying the quality of the constructions. Dissertation thesis is focused on evaluating the quality of the execution of sprayed concrete without accelerating additives applied by spraying by a dry way manually-sprayed. The quality of shotcrete was judged on the basis of standardized both non-destructive and destructive methods using sprayed samples. The quality of shotcrete was assessed in terms of strength of sprayed concrete in pressure, density and homogeneity judged on the basis of the velocity of sound samples. The destructive method was carried out on the core samples which were pressured on the hydraulic press, as the non-destructive method was used ultrasonic passageway method based on the propagation velocity of the ultrasonic pulse. On the basis of our results and their mutual correlations, it has been proposed the modifications of the general equal used for predicting the strength of the sprayed concrete tested by our strength class, which leads to a potential reduction in the number of cores on the real structure, and therefore reduce the price of implementation of qualitative tests and increase effectiveness of carrying out tests on the construction place.
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The Processing of Climatologic Records from Experimental Locations in Kyrgyzstan and the Synoptic-climatologic Interpretation Thereof
Sýkorová, Petra ; Huth, Radan (advisor) ; Pokorná, Lucie (referee)
The Charles University Faculty of Science KFGG team took part in an intensive research in the area of Kyrgyz glacial lakes. The collecting of records from three meteorological stations in the locations of Kolor (2,700 m above sea level) and Adygine (3,500 and 3,800 meters above sea level) was part of the research. The aim of this thesis was to analyze the homogeneity of climatic data measured in experimental locations using the SNHT method (Standard Normal Homogeneity Test), process the data using general climatological processes, create a classification of circulation types for the area of interest using Jenkinson's and Collinson's method, and finally, to quantify the relationships between individual circulation types and the values of chosen climatic elements. The analysis results are homogenized climatic sets for the Adygine H station (3,800 m above sea level) and a summary of basic statistics and trends of climatic elements in the area. Furthermore, a catalogue of circulation types was created for the period from August 2007 to July 2011, and finally, the relationships between individual circulation types and manifestations of climate elements (air temperature, precipitation and global radiation). The results of this thesis may be used to identify the types connected with bursts of glacial...
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