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Chemical and microstructural analysis of asphalt concrete in the former brewery in Plasy (CR)
Frankeová, Dita; Slížková, Zuzana; Náhunková, Pavla
2023 - Czech
TG analysis revealed a proportion of organic matter (asphalt) in the total mass of the material in the amount of 14% by weight and the content of calcium carbonate in the material in the amount of 53% wt. Calcium carbonate is probably in the form of limestone powder as a fine filler. The coarse fraction of the aggregate is represented by stone grains of size 2-10 mm (33% by weight). TG analýzou byl zjištěn podíl organické hmoty (asfaltu) na celkové hmotě materiálu ve výši 14 % hm. a obsah uhličitanu vápenatého v materiálu v množství 53 % hm. Uhličitan vápenatý je pravděpodobně přítomen ve formě vápencového prášku, jako jemného plniva. Hrubou frakci kameniva představují kamenná zrna o velikosti 2-10 mm (33 % hm.).
Keywords:
thermal analysis; asphalt floors; asphalt concrete; tar; asphalt composite
Available at various institutes of the ASCR
Chemical and microstructural analysis of asphalt concrete in the former brewery in Plasy (CR)
TG analysis revealed a proportion of organic matter (asphalt) in the total mass of the material in the amount of 14% by weight and the content of calcium carbonate in the material in the amount of 53% ...
Microscopic analysis of the mortars sampled from the Hradenín fortress
Frankeová, Dita; Bauerová, Pavla; Vondráčková, Michaela; Slížková, Zuzana
2023 - Czech
Two mortar samples and one sample of plaster of the exterior facade from the Gothic fortress Hradenín were examined using an electron microscope. The aim of study was to determine the type of mortar binder and to find out the technological procedure of surface coating application. Pomocí elektronového mikroskopu zkoumány 2 vzorky malty z gotické tvrze Hradenín a jeden vzorek omítky venkovní fasády z téhož objektu. Cílem našeho zkoumání bylo zejména určit druh pojiva malt a pokusit se u vzorku omítky zjistit technologický postup aplikace povrchového nátěru.
Keywords:
mortars; plasters; coatings
Available at various institutes of the ASCR
Microscopic analysis of the mortars sampled from the Hradenín fortress
Two mortar samples and one sample of plaster of the exterior facade from the Gothic fortress Hradenín were examined using an electron microscope. The aim of study was to determine the type of mortar ...
Damage detection study for a pedestrian cable-stayed bridge using ANSYS
Bayer, Jan; Kawulok, Marek; Urushadze, Shota
2023 - English
In connection to development of new testing techniques for bridges at ITAM, a theoretical damage detection case study was performed for a cable stayed bridge over the Vltava River at Lužec. The results recognise the most susceptible loading modes which should be identified exactly during the in-situ measurements.
Keywords:
cable stayed bridges; structural health monitoring; ANSYS
Available at various institutes of the ASCR
Damage detection study for a pedestrian cable-stayed bridge using ANSYS
In connection to development of new testing techniques for bridges at ITAM, a theoretical damage detection case study was performed for a cable stayed bridge over the Vltava River at Lužec. The ...
Effect of the long-term storage methods on the stability of cartilage biomechanical parameters
Žaloudková, Blanka; Sekorová, Š.; Kopecká, B.; Kytýř, Daniel
2023 - English
Long-term stability of the tissue product in terms of mechanical parameters is a key factor for its expiration date. For the investigation of storage effects on the cartilage tissues the experimental mechanical loading test combined with XCT scanning for the irregular shape inspection was performed. The samples were preserved according to three different protocols using the deep-freezing and two types of saline solution preservation. The stability of the biomechanical parameters was tested within annual intervals. All samples were subjected to uni-axial compression loading using the in-house developed compact table top loading device in displacement-driven mode. Based on the measurements, the results are represented in the form of stress-strain curves and quantified as elastic modulus and ultimate compression stress. It can be concluded that no significant difference was found in neither the mechanical properties of the samples nor in the effects of each preservational method.
Keywords:
stability study; cartilage; biomechanical characterisation; compression loading; XCT imaging
Available at various institutes of the ASCR
Effect of the long-term storage methods on the stability of cartilage biomechanical parameters
Long-term stability of the tissue product in terms of mechanical parameters is a key factor for its expiration date. For the investigation of storage effects on the cartilage tissues the experimental ...
The effect of the backfill on the integrity of a buried pipeline upon heavy-duty vehicle crossings
Gajdoš, Lubomír; Šperl, Martin; Slížková, Zuzana; Drdlová, M.
2023 - English
The aim of this work was to determine stresses in the wall of a buried empty gas pipeline caused by the weight of backfill as well as by heavy-duty vehicles crossing the pipeline, and, on their basis to assess the applicability of protective sleeves. A buried pipeline with zero internal pressure of transported medium (empty pipeline) differs from an unburied pipeline by the vertical load due to the weight of the backfill which causes an ovalness of the circular cross section of the pipeline. This leads to the rise of through-wall bending stresses with the tensile stress at the outside surface at the 3 and 9 o´clock positions and compressive stress at the inside surface. At the 6 and 12 o´clock positions the stresses are tensile at the inside surface and compressive at the outside surface. The current depth of soil cover above gas pipelines is 0.5 m. For pipes DN500, t ~ 6.5 mm the through-wall bending stress is found to be σb ≈ ±10 MPa. In comparison with the yield stress of pipeline material, this stress is negligible. The situation is changed when heavy-duty vehicles cross the pipeline. For example, when a MAN truck with the mass load 3270 kg acting on a single wheel of the front axle crosses this pipeline, the pressure transmitted to the pipe will cause the through-wall bending stress σb ≈ ±76 MPa. This stress is superimposed to that of the backfill to give the total value ±86 MPa. When dead loads, imposed by backfill cover, together with live loads, caused by truck-wheel loads, are excessive a crushing of side walls of the pipeline and/or ring buckling of the pipe cross section can happen.
Keywords:
gas pipeline; pressure; buried pipeline
Available at various institutes of the ASCR
The effect of the backfill on the integrity of a buried pipeline upon heavy-duty vehicle crossings
The aim of this work was to determine stresses in the wall of a buried empty gas pipeline caused by the weight of backfill as well as by heavy-duty vehicles crossing the pipeline, and, on their basis ...
Experimental evaluation of aluminothermic welds
Zeman, L.; Valach, J.; Zlámal, P.; Krčmářová, N.; Koudelková, Veronika; Zeman, J.
2023 - English
The article presents a study of the mechanical processes occurring during the aluminother-mic reaction using experimental methods (strain gauges, digital image correlation, thermography,scanning electron microscopy, profilometry). The aluminothermic reaction is a highly efficient weldingmethod due to its exothermic behaviour, however, it places considerable demands not only on thewelding technique, but also on the capabilities of the experimental methods used - these limitationsare also discussed in the article. The aluminothermic reaction is associated with the formation of alocalised heat source with a time evolution dictated by the technological procedure, which manifestsitself in heat propagation to the surrounding weld material. The unequal evolution of the temperaturefield is the fundamental cause of the appearance of the heat affected zone or local deformations orsurface curvature, which was the focus of the experimental methods deployed above and the results ofwhich are shown in the article.
Keywords:
aluminothermic reaction; train gauges; hardness; profilometry; scanning electron microscope
Available at various institutes of the ASCR
Experimental evaluation of aluminothermic welds
The article presents a study of the mechanical processes occurring during the aluminother-mic reaction using experimental methods (strain gauges, digital image correlation, thermography,scanning ...
Acta Polytechnica CTU Proceedings. Vol. 42 (2023)
Kytýř, Daniel; Doktor, T.; Zlámal, Petr
2023 - English
The YSESM symposium provides a forum for young researchers and engineers, PhD students and students dealing with subjects of experimental mechanics. The Symposium concentrates on current work in all areas of experimental research and its application in solid and fluid mechanics. The topic will particularly concern to: Conventional and Advanced Experimental Methods in Solid and Fluid Mechanics, Non-Destructive Testing and Inspection, Measurements in Material Science, Computer Assisted Testing and Simulation, Engineering Design Simulation, Hybrid Methods, Experimental Techniques – Numerical Simulation, Optical Methods and Image Processing, Measurements in Biomechanics, Sensor Techniques for Micro- and Nano-Applications, Measurement Methods for Forensic Engineering.
Keywords:
experimental mechanics; fluid mechanics; mechanics of solids
Available at various institutes of the ASCR
Acta Polytechnica CTU Proceedings. Vol. 42 (2023)
The YSESM symposium provides a forum for young researchers and engineers, PhD students and students dealing with subjects of experimental mechanics. The Symposium concentrates on current work in all ...
Analyzing stochastic stability of a gyroscope through the stochastic Lyapunov function
Náprstek, Jiří; Fischer, Cyril
2023 - English
The text delves into the application of first integrals in the construction of Lyapunov functions for analyzing the stability of dynamic systems in stochastic domains. It emphasizes the distinct characteristics of first integrals that warrant the introduction of additional constraints to ensure the essential properties required for a Lyapunov function. These constraints possess physical interpretations associated with system stability. The general approach to testing stochastic stability is illustrated using the example of a 3-degrees-of-freedom system representing a gyroscope.
Keywords:
stochastic stability; Lyapunov function; first integral; gyroscope
Available at various institutes of the ASCR
Analyzing stochastic stability of a gyroscope through the stochastic Lyapunov function
The text delves into the application of first integrals in the construction of Lyapunov functions for analyzing the stability of dynamic systems in stochastic domains. It emphasizes the distinct ...
Survey of the Přibyslav underground corridor by ground penetrating radar
Válek, Jan; Kotková, Kristýna; Kozlovcev, Petr
2023 - Czech
A non-destructive survey of the Přibyslav underground corridor using ground penetrating radar was carried out. The aim of the measurement was to verify the existence of possible structures hidden under the current surface of the corridor. The survey located the backfill above the bedrock of the underground corridor and other changes in the structure. Byl realizován nedestruktivní průzkum Přibyslavské štoly pomocí zemního radaru. Cílem měření bylo ověření existence případných prostor skrytých pod současným povrchem štoly. Průzkum lokalizoval násyp nad skalním podložím štoly a další nehomogenity.
Keywords:
ground penetrating radar (GPR); cultural heritage; non-destructive testing
Available at various institutes of the ASCR
Survey of the Přibyslav underground corridor by ground penetrating radar
A non-destructive survey of the Přibyslav underground corridor using ground penetrating radar was carried out. The aim of the measurement was to verify the existence of possible structures hidden ...
Laboratory microscopic survey of the stratigraphy of colored coatings on building materials of the Morzinski Palace building in Nerudova st. Prague 1
Slížková, Zuzana; Náhunková, Pavla; Bauerová, Pavla; Vondráčková, Michaela
2023 - Czech
Stratigraphic analysis of the color coatings on the facade of the Morzín Palace in Prague in order to determine the color of the facade for the future restoration of the building. Stratigrafická analýza barevných nátěrů na fasádě Morzínského paláce v Praze za účelem určení barevnosti fasády pro návrh obnovy a restaurování budovy.
Keywords:
stratigraphy; colored layers; coatings; microscopy
Available at various institutes of the ASCR
Laboratory microscopic survey of the stratigraphy of colored coatings on building materials of the Morzinski Palace building in Nerudova st. Prague 1
Stratigraphic analysis of the color coatings on the facade of the Morzín Palace in Prague in order to determine the color of the facade for the future restoration of the building.
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