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Brass Corrosion Layers Reduction by Low-Pressure Low-Temperature Plasma
Řádková, Lucie ; Slavíček,, Pavel (referee) ; Zahoran,, Miroslav (referee) ; Krčma, František (advisor)
This thesis presents results of the corrosion layers removal which could be found on the archaeological artefact surfaces. The low pressure low temperature plasma reduction was used for this purpose. Brass samples were chosen for this study. Two different ways have been used to form model corrosion layers. Several sets of corrosion layers were prepared in laboratory in two different corrosion atmospheres, namely ammonia atmosphere and atmosphere of hydrochloric acid. These samples were placed into desiccator. Small quantities of sand were added to some sets of samples so samples with sandy incrustation were prepared. The corrosion layers had been usually formed during four weeks. The second way, which was used to prepare model corrosion layer, was the natural corrosion in soil or compost. In this case, the corrosion layers had been formed approximately 2 years. The samples were treated in the low pressure (150 Pa) cylindrical Quartz reactor (90 cm long and 9.5 cm in diameter) with a pair of external copper electrodes connected via the matching network to a radiofrequency generator (13.56 MHz). The flows of working gases were set by independent mass flow controllers. Whole system was continuously pumped by the rotary oil pump which was separated from the discharge reactor by liquid nitrogen trap with aluminium chips eliminating dust and reactive species from the gas flow. Each sample was placed on a glass holder at the reactor center. Plasma was generated in pure hydrogen or in mixture of hydrogen and argon. Total flow of working gas was 50 sccm. Different ratios of gas mixture were tested, the ratio 30 sccm hydrogen and 20 sccm argon flows was the best. RF discharge was used in a continuous and pulsed regime. Pulsed mode was carried out with various duty cycle at the frequency of 1000 Hz. There were two ways of temperature monitoring. The sample temperature during the treatment was monitored by a K-type thermocouple installed inside the sample in the first case. Thermometer optical probe was connected to the sample surface by a small stainless plate and allowed continuous sample temperature monitoring in the second way. Safe object temperature for copper and copper alloys is 100–120 °C. To avoid exceeding this temperature, power control or the duty cycle in pulse mode were automatically controlled if thermometer optical probe was used. Plasma chemical treatment is based on generation of reactive atomic hydrogen in plasma discharge. The main reactions during reduction were reactions between oxygen and chloride contained in the corrosion layer and the hydrogen ions and neutral atoms generated in the plasma. These reactions create an unstable OH radical, which emits light in the region of 306–312 nm. This radiation was detected by the optical emission spectroscopy using Ocean Optics HR4000 spectrometer with 2400 gr/mm grating. Data obtained from this method were used to calculate rotational temperatures and integral intensity of OH radicals that were used for the process monitoring. Corrosion layer was not completely removed during the reduction, but due to the reactions which occur in the plasma corrosion layer became brittle and after plasma chemical treatment can be removed easily. The SEM-EDS material analyses were carried out before and after treatment of some samples. Some samples were analysed by XRD analysis. EDS analysis showed that amount of oxygen and chloride was decreased, mainly at 400 W pulse mode.
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The archaeological evidence of relations between Scandinavia and North-West Russia in the early middle ages
Trusova, Daria ; Košnar, Lubomír (advisor) ; Štefan, Ivo (referee)
This work is devoted to the contacts between North-Western Rus' and Scandinavia in the early Middle Ages. The work pays attention to disclosure of the nature of the Scandinavians stay in the territory of Rus'. This is done through the description and evaluation of the archaeological finds in the most important economic centers along the trade routes of the Middle Ages. Information on research in the territory of Russia and found objects is taken from the modern Russian scientific publications. In the work the modern vision of the presence of Scandinavian immigrants is disclosed. The result is the recognition of northerners as permanent inhabitants in several economic centers along with the Finno- Ugric and Slavic population. Keywords Scandinavia, North-West of Russia, archaeological finds, trade and craft centers, early Middle Ages
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Medieval bell founding. Bell founding and archaeology in the Middle Ages and the Early Modern period.
RYCHLÍK, Martin
The bachelor thesis examines bell founding in Bohemia in the Middle Ages and the Early Modern period of modern history, primarily from an archaeological viewpoint. The archaeological part of the bachelor thesis, which is central to the whole paper, relies on findings of works on both moveable and immoveable archaeological evidence of bell founding from several regions of Bohemia. The goal of the bachelor thesis is to introduce a new picture of bell founding from various perspectives. The paper comprises not only an archaeological point of view, which focuses on archaeological finds of bells and bell fragments and archaeological evidence from bell foundries, but also a campanological and historical point of view, presenting the current state of research in the field. In terms of methodology, the bachelor thesis uses description, transcription, induction, deduction, analysis, synthesis, and a synchronous approach to the matter. Attached are: sketches and photography of archaeological finds, sketches and photography of immovable archaeological finds, tabular summaries and graphs.
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Mutation rates and dispersal of human populations
Kulichová, Iva ; Černý, Viktor (advisor) ; Šolc, Roman (referee)
This bachelor thesis deals with estimation of mutation rate of DNA and its use for dating of the first settlement of Sahul. The first part describes direct approach for the estimation of the mutation rate, based on the analysis of pedigrees and indirect approach based on phylogenetic analysis. The weaknesses of these methods are presented as well, as they distort the resulting values of the mutation rate and therefore it is necessary not to ingore them. Some alternatives of calibration methods for the direct and the indirect estimation of the mutation rate are introduced, for example based on archaeological samples. The subsequent section discusses the characteristic mutation rate of mitochondrial and nuclear DNA estimated utilising the direct and the indirect approach. The difference between pedigree and phylogenetic rates appears especially in the mitochondrial DNA, because of selection.The second part outlines the evolutionary path leading to anatomically modern human in Africa and his expansion into Eurasia based on the fossil record dated 45,000 years ago. Particular attention is paid to the settlement of Sahul in archaeological and molecular point of view. Based on the combination of these sources of information, it is possible to conclude that the settlement of Sahul passed from Africa along...
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The archaeological evidence of relations between Scandinavia and North-West Russia in the early middle ages
Trusova, Daria ; Košnar, Lubomír (advisor) ; Štefan, Ivo (referee)
This work is devoted to the contacts between North-Western Rus' and Scandinavia in the early Middle Ages. The work pays attention to disclosure of the nature of the Scandinavians stay in the territory of Rus'. This is done through the description and evaluation of the archaeological finds in the most important economic centers along the trade routes of the Middle Ages. Information on research in the territory of Russia and found objects is taken from the modern Russian scientific publications. In the work the modern vision of the presence of Scandinavian immigrants is disclosed. The result is the recognition of northerners as permanent inhabitants in several economic centers along with the Finno- Ugric and Slavic population. Keywords Scandinavia, North-West of Russia, archaeological finds, trade and craft centers, early Middle Ages
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"Kaptorgas" in early Middle Ages
Feit, Jan ; Otavský, Karel (advisor) ; Novák, David (referee)
Presented BA thesis "Early medieval kaptorga" dealing with metal caskets which were worn on the neck by the women in the early medieval period and called by the archaeologists "kaptorgas".This work summarises available archeological material together with the published finds of kaptorgas from Bohemia and Moravia. Introductional part of the work dealing with questions of origin, purpose and social status of women which worn them. The main part of this work contains typology a complete register of kaptorgas sorted by archeoligical locality. Detailed description and style analysis accompanied with pictures is the other important part of this work. The relevant information are arranged in synoptical table.
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Brass Corrosion Layers Reduction by Low-Pressure Low-Temperature Plasma
Řádková, Lucie ; Slavíček,, Pavel (referee) ; Zahoran,, Miroslav (referee) ; Krčma, František (advisor)
This thesis presents results of the corrosion layers removal which could be found on the archaeological artefact surfaces. The low pressure low temperature plasma reduction was used for this purpose. Brass samples were chosen for this study. Two different ways have been used to form model corrosion layers. Several sets of corrosion layers were prepared in laboratory in two different corrosion atmospheres, namely ammonia atmosphere and atmosphere of hydrochloric acid. These samples were placed into desiccator. Small quantities of sand were added to some sets of samples so samples with sandy incrustation were prepared. The corrosion layers had been usually formed during four weeks. The second way, which was used to prepare model corrosion layer, was the natural corrosion in soil or compost. In this case, the corrosion layers had been formed approximately 2 years. The samples were treated in the low pressure (150 Pa) cylindrical Quartz reactor (90 cm long and 9.5 cm in diameter) with a pair of external copper electrodes connected via the matching network to a radiofrequency generator (13.56 MHz). The flows of working gases were set by independent mass flow controllers. Whole system was continuously pumped by the rotary oil pump which was separated from the discharge reactor by liquid nitrogen trap with aluminium chips eliminating dust and reactive species from the gas flow. Each sample was placed on a glass holder at the reactor center. Plasma was generated in pure hydrogen or in mixture of hydrogen and argon. Total flow of working gas was 50 sccm. Different ratios of gas mixture were tested, the ratio 30 sccm hydrogen and 20 sccm argon flows was the best. RF discharge was used in a continuous and pulsed regime. Pulsed mode was carried out with various duty cycle at the frequency of 1000 Hz. There were two ways of temperature monitoring. The sample temperature during the treatment was monitored by a K-type thermocouple installed inside the sample in the first case. Thermometer optical probe was connected to the sample surface by a small stainless plate and allowed continuous sample temperature monitoring in the second way. Safe object temperature for copper and copper alloys is 100–120 °C. To avoid exceeding this temperature, power control or the duty cycle in pulse mode were automatically controlled if thermometer optical probe was used. Plasma chemical treatment is based on generation of reactive atomic hydrogen in plasma discharge. The main reactions during reduction were reactions between oxygen and chloride contained in the corrosion layer and the hydrogen ions and neutral atoms generated in the plasma. These reactions create an unstable OH radical, which emits light in the region of 306–312 nm. This radiation was detected by the optical emission spectroscopy using Ocean Optics HR4000 spectrometer with 2400 gr/mm grating. Data obtained from this method were used to calculate rotational temperatures and integral intensity of OH radicals that were used for the process monitoring. Corrosion layer was not completely removed during the reduction, but due to the reactions which occur in the plasma corrosion layer became brittle and after plasma chemical treatment can be removed easily. The SEM-EDS material analyses were carried out before and after treatment of some samples. Some samples were analysed by XRD analysis. EDS analysis showed that amount of oxygen and chloride was decreased, mainly at 400 W pulse mode.
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Návrh na řešení veřejného prostranství s archeologickými nálezy základů kostela s. Marka a školy Jednoty bratrské v lokalitě Na Marku v Přerově
Kolaříková, Aneta
The bachelor thesis, due to the selected topic, deals with general concept of torso architecture that represents a specific category of architectural heritage. It outlines ways of uncovering, legal protection and presentation of torso architecture in situ , as a historical trace, which remains in its fragmentary form in many places legible even at present. With specific Czech as well as foreign examples, are these different ways of presenting illustrated. The analytical part contains the general characteristics of the city Přerov, contains review of historical urban development and is supplemented by several spatially functional analyzes relating to housing and greenery. In a design part are then synthesized all the sub- surface analysis solutions and open at the garden architectural design, which aims to bring potential visitors to the city and present designed flat as an important layer in the history of the city and offer residents a comfortable place for leisure activities.
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