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Scientific report. Tomography of an archaeological finding – a container with coins
Vopálenský, Michal ; Kumpová, Ivana
The aim of the research is to visualize an archaeological finding of coins (mostly Ag/Cu alloy) in a ceramic container by means of the computed tomography. The artifact is dated to the first half of the 15th century, the visible coins are Prague Groschen and Vienna Pfennigs. The tomographical model should in an ideal case enable to identify the number and type of the coins and other possible materials. Besides of coins, the finding can contain wood, other organic materials (leather) and soil. The container is approx. 20 cm high, with the maximum diameter of approx. 15 cm. The weight of the artifact is 3.8 kg.
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Scientific report. Tomography of natural gold findings
Vopálenský, Michal ; Kumpová, Ivana
The aim of the research was to visualize the distribution of gold in natural findings by means of the computed tomography (CT). Gold is present as an alloy with silver (gold being prevalent at least close to the surface, where X-ray fluorescence is applicable). The findings are not homogenous nugets, but stones where gold is distributed in the parent rock (quartz). The purpose of the CT is to visualize the structure of gold in quartz, localize cavities and other structural features.
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Evaluation of self-healing in concrete by means of analytical techniques
Aspiotis, K. ; Sotiriadis, Konstantinos ; Kumpová, Ivana ; Mácová, Petra ; Badogiannis, E. ; Tsivilis, S.
In the present work, the self-healing process in concrete was evaluated using analytical techniques. For this purpose, two concrete mixes of different composition (one used as reference) were prepared with a W/B of 0.45. The self-healing process was triggered by the introduction in the concrete mix of a commercial expansive admixture (calcium sulfo-aluminate), two dicarboxylic acids, and sodium carbonate salt. After 28 days curing in water, the specimens were artificially cracked (crack width ≈ 400 μm) and then again water-cured for 40 days until self-healing occurred. The progress of self-healing was investigated with a stereo-microscope at 40, 50 and 60 days. The efficiency of the process was evaluated using micro-Raman spectroscopy and X-ray micro-computed tomography (XmCT). Significant reduction in the crack width was observed as a result of filling the crack with calcite generated during the self-healing process. In some cases, the crack was completely healed. The experimental methodology used provided new insights into the evolution of the self-healing phenomenon in concrete.
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Quantification of microstructural changes in limestone cement paste stored in sulfate environment at low temperature
Sotiriadis, Konstantinos ; Hlobil, Michal ; Machová, Dita ; Mácová, Petra ; Viani, Alberto ; Vopálenský, Michal
Samples of cement paste based on mixed cement with limestone admixture were stored in a magnesium sulfate solution for 6 months at 5 ° C to monitor the development of sulfate corrosion and its effect on microstructure. The extent of corrosion was evaluated by several different techniques. The paste samples were scanned at monthly intervals by X-ray tomography for non-destructive quantification of the pore structure and extent of damage, along with a description of the phase changes in the microstructure using X-ray diffraction and infrared spectroscopy. Compressive strength testing confirmed the effect of corrosion on the mechanical resistance of the samples. The results show a rapid course of degradation propagating in an irregular band, caused primarily by the formation of expandable sulfur-based corrosion products, the consequent crack formation and loss of internal cohesion of the material. The occurrence of both ettringite and thaumasite and gypsum was confirmed in the damaged parts.
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Celtic swords
Kumpová, Ivana
The work was focused on the development of the methodology using X-ray tomographic imaging for exploration of metal-based historical artefacts. In the laboratory of X-ray tomography, two objects were examined by this method - two tomography measurements of the early medieval sword in the pre-conservative phase were taken, supplemented by imaging if the bronze bracelet of the same period. The survey was conducted to reveal the technology of production, decoration and possible damage.
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Concrete with steel reinforcement
Kumpová, Ivana ; Jandejsek, Ivan ; Vavřík, Daniel
The work was focused on X-Ray tomography and creating of 3D computer models of ten concrete samples with various steel reinforcement contents and different production technology. From these models, the volume ratios of individual components (concrete: reinforcement: pores) and directional layout of individual fibers were calculated.
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Long bone measurements
Kumpová, Ivana ; Vavřík, Daniel
The work was focused on X-Ray tomography and creating of 3D computer models of historically valuable long bones. Selected slices of reconstructed data in 50% and 35% of each bone length and the entire 3D reconstructions of all specimens, were stored on the supplied medium in DICOM format and forwarded to the client representative together with an extensive measurement protocol.
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