Institute of Theoretical and Applied Mechanics

Institute of Theoretical and Applied Mechanics 1,323 records found  beginprevious61 - 70nextend  jump to record: Search took 0.01 seconds. 
Long term monitoring of cracks in masonry of the Fürstenberk Palace in Prague
Drdácký, Miloš ; Zíma, Pavel
Results of long-term monitoring of the behavior of cracks in the masonry of a Baroque palace exposed to the cyclical effects of temperature and humidity. Determining the rate of permanent change in crack width to predict future behavior.
The ruins of a medieval castle and modern technology
Novotný, Jakub
The topic of the paper is the relationship between torsional architecture and modern technologies. First, the Report assessing innovative restoration techniques, technologies and materials used in conservation is briefly presented, which provides an overview of the most used techniques, technologies and materials for the exploration and protection of this type of monuments. Furthermore, the paper provides an overview of the progress and results of the regional cooperation project Technological research of the Štamberk castle ruins in the wider context of the region with an emphasis on the use of modern technologies.
Survey of the terrain and structures under the floor of The Mother of God Church (The Telč Old Town)
Válek, Jan ; Kotková, Kristýna ; Kozlovcev, Petr
A non-destructive survey of the building structures hidden under the current level of the Church of the Mother of God in the Old Town of Telč was carried out using ground-penetrating radar. The survey revealed the occurrence of hidden constructions that are related to the current concept of the church and its construction solution.
Contribution to the investigation of the oldest history of the Telč Castle
Drdácký, Miloš ; Buzek, Jaroslav
The summary research report presents the results of research into the oldest building relics of Telč Castle. It uses radiocarbon dating of skeletal remains, non-destructive surveying by thermal imaging and ground-penetrating radar, and 3D photogrammetric reconstructions of the shape and dimensions of architectural elements. It also analyzes Templar traces in Telč region and in the wider region.
Analysis of displacement measured during the compressive testing of cylindrical specimens
Frantík, P. ; Lisztwan, D. ; Kumpová, Ivana ; Daněk, P. ; Rovnaníková, P. ; Keršner, Z.
The paper deals with selected aspects of the analysis of the displacement and deformation stiffness of cylindrical specimens during compressive tests. A developed correction model is presented, and two types of material were selected for the adjustment of the correction model: concrete from an existing structure, and alkali-activated aluminosilicate composite. The correction model was calibrated using the test response of a steel cylinder.
Construction of the Lyapunov function reflecting the physical properties of the model
Náprstek, Jiří ; Fischer, Cyril
Practical experience shows that the random excitation component can affect the system response and its dynamic stability not only negatively but also positively. Such mechanisms are usually developed heuristically and are often not sufficiently justified theoretically. The paper presents a possibility of using the properties of first integrals for the construction of a Lyapunov function for the analysis of a dynamic system stability in the stochastic domain. In such case, the Lyapunov function itself contains information on the examined system and, consequently, it is able to provide a more detailed insight into the system stability properties. The procedure is illustrated by a nonlinear SDOF example.
Analysis of van der Pol equation on slow time scale for combined random and harmonic excitation
Náprstek, Jiří ; Fischer, Cyril
Vortex shedding represents one of the most important processes that constantly attract the attention of experimental and theoretical research. A number of non-linear effects arise from the fluid-structure interaction. The non-stationary response in the vicinity of the lock-in region has a quasi-periodic character, beating frequency of which varies considerably with the distance from the lock-in frequency. This property is significantly affected by the assumption of combined random and harmonic excitation. This paper describes several details that contribute to the probabilistic characteristics of the system on a time-slow scale using partial response amplitudes.
Chemical and microstructural analysis of plaster sampled from the castle Sychrov (CR) – Breton tower
Slížková, Zuzana ; Frankeová, Dita ; Bauerová, Pavla ; Náhunková, Pavla
The analysed mortar contains 76.5% by weight quartz sand and 23.5% wt. the lime binder - it is highly hydraulic lime. The aggregate of the mortar is made up mostly of quartz. The hydraulicity of the contained lime binder is evidenced by the presence of belitic clinkers, a strongly inhomogeneous microstructure (typical alternation of dense, Ca-enriched parts and more porous decalcified areas) and the presence of silicate components in varying degrees of reaction. It is suggested that the hydraulic binder used could have been artificially prepared by mixing lime with a hydraulic silicate additive.
Selection of mortars samples for radiocarbon dating
Válek, Jan ; Kozlovcev, Petr ; Fialová, Anna ; Kotková, Kristýna ; Frankeová, Dita ; Skružná, Olga ; Maříková-Kubková, Jana ; Tomanová, Pavla ; Herichová, Iva ; Světlík, Ivo ; Pachnerová Brabcová, Kateřina ; Šimek, Pavel
Radiocarbon dating of organic residues may not always correctly determine the age of analysed historic mortars. Therefore, it seems advantageous to use of carbon dating of the carbon contained in the structure of the lime mortar, which will provide representative data of the age of the investigated structure. The methodology presents basic instructions and rules for sample selection, processing, and evaluation. The aim of this methodology is the identification of cases where the radiocarbon dating of a binder is appropriate and to define the reasons why some binder systems fail to provide relevant results.
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Preparation of mortars samples for radiocarbon dating by mechanical separation
Válek, Jan ; Kotková, Kristýna ; Fialová, Anna ; Kozlovcev, Petr ; Králová, Karolína ; Světlík, Ivo ; Pachnerová Brabcová, Kateřina
The methodology establishes the procedure for mechanical separation of the binder from the mortars to determine their age using the radiocarbon method. Along with the procedure, there is also a method of verifying the quality of purification using optical microscopy supplemented with cathode luminescence. The methodology is developed on the basis of the current state of knowledge and presents the basic sample preparation procedure in the form of a detailed description of the proven method of mechanical separation of the binder from lime mortar samples together with possible problems and an evaluation of the separation quality.
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Institute of Theoretical and Applied Mechanics : 1,323 records found   beginprevious61 - 70nextend  jump to record:
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