National Repository of Grey Literature 352 records found  1 - 10nextend  jump to record: Search took 0.02 seconds. 
Current Problems in 2D Numerical Modelling of Water Flow in the River Channels
Grmelová, Eliška ; Skokan, Jiří ; Juriga, Jan ; Chrástová, Veronika ; Pospíšilík, Šimon
Currently, the use of two-dimensional numerical models in modelling water flow in river channels and floodplains is quite common. The quality of hydraulic calculation results is influenced by the number of input parameters. However, crucial in this context is primarily the availability of calibration data. Commonly used data from historical flood records are often burdened with significant uncertainties and, in many cases, are completely lacking. One option to ensure suitable calibration data is to measure flow rates and velocity fields in selected calibration profiles, e.g., using the ADCP method (Acoustic Doppler Current Profiler). The presented article showcases the authors' experiences with the calibration of a 2D numerical model applied to a real location, specifically using the mentioned method. The focus of the calibration lies mainly in the values of Manning’s roughness coefficients and parameters of turbulent models. The conclusion of the article includes a discussion of the results and recommendations for further research directions in the field, which appear promising for practical applications.
Numerical Analysis of Creep and Shrinkage Behaviour of Concrete During Laboratory Tests Using Advanced Constitutive Model
Šindelářová, Daniela ; Chalmovský, Juraj
This paper utilizes a time-dependent elastoplastic material model to predict the creep and shrinkage behaviour of laboratory samples via the Finite Element Method (FEM) analysis. After describing the time-dependent behaviour of concrete, the influence of creep input parameters of the material model is analysed in a parametric study. Finally, the values of creep and shrinkage input parameters are calibrated based on real tests and subsequent usage in the numerical modelling of geotechnical structures is discussed.
Tyre Temper. Meauserement on Moving Vehicle with Use of Infrared Pyromether OS100
Morávek, David ; Rasch, František (referee) ; Blaťák, Ondřej (advisor)
Bc. David Morávek Tyre temperature measurement on moving vehicle with of infrared pyrometer OS100 MT, IAE, 2008, page 70, picture 41 Problemacy of recording the temperature and tyre pressure on driven car is processed in this diploma work. Suitable measuring chain was set up. Censor holders for this type of measurement were designed and produced. Driving exams and tests are depicted in this work, too. We came to the conclusion that tyre temperature depends on lengthways and transverse acceleration of the car and also on it’s load.
Documentation of Balkónová and Balkóta passages in Býčí skála cave
Velecká, Kateřina ; Kuruc, Michal (referee) ; Kratochvíl, Radim (advisor)
The bachelor thesis deals with documentation of the part of cave system Býčí skála, namely of the passages Balkónová chodba, Balkóta and part of the passage Kóta 314 in the form of a ground plan, extended longitudinal section and cross sections in the scale of 1:250. The thesis contains a short description of the locality, steps from recognition and completion of the existing measuring network to a detailed survey and creating of the final map in the JTSK coordinate system and the Bpv height system. For the detailed measurement was used a special speleological measuring method utilizing a device DistoX2 with a tablet and the program TopoDroid for creation of the measuring sketch.
Measurement and evaluation of flows in sewer networks
Haška, Aleš ; Prax,, Petr (referee) ; Raclavský, Jaroslav (advisor)
Measuring flow rate, water surface and rainfall are the crucial inputs for the calibration of the hydraulic model. This bachelor’s thesis presents mathematical models and measuring devices for the sewer networks. This thesis summarises the measuring devices that are currently available and used on the sewer network. Furthermore, theory of random and systematic errors is discussed. In the second section, this theory is implemented in the chosen area for the sewer network in Znojmo. On the 9. 9. 2020, three ultrasonic measuring devices (type ISCO 2150 with AV sensor) and one device for measuring water surface (type IJINUS) were installed in this area. This thesis provides continuous measurements which are then applied for the calibration of the hydraulic model. On completion of this thesis it is necessary to continue to calibrate and verify the model in order to increase accuracy and be more precise.
Coaxial multiplexer for automatic measurement of AC current
Boštík, Ondřej ; Klusáček, Stanislav (referee) ; Havlíková, Marie (advisor)
Master’s thesis in the theoretical part deals with literature review on the topic of measurement errors and measurement uncertainties. The practical part deals with the simulation of additional capacitive and resistive load on the amplitude and phase error during shunts based measurement. For this simulation is used mathematical apparatus of cascade matrix of two-ports and their connections. For the actual simulation is used script for MATLAB. Furthermore, the work deals with the design of voltage follower to eliminate simulated errors and its practical realization. The last part deals with the design of the coaxial multiplexer for switching current shunts developed in the Czech Metrological Institute in Brno.
The expression of the accuracy of the gauge and measurement
Svobodová, Helena ; Koška, Petr (referee) ; Pernikář, Jiří (advisor)
The bachelor thesis deals with the issue of measurement, accuracy of measuring instruments and their expressing. It outlines the legislative basis of metrology in the Czech Republic and interprets the definitions of basic terms used in metrology. These definitions are listed in the new edition of International dictionary of metrology (VIM 3:2007). It specifies and exemplifies measurement errors and presents possibilities of their elimination. Further, it describes a simple way of measurement uncertainty determination. The aim of this thesis is to explain the issue in a way that it is understandable and can be applicable for the common metrology practice.
Non-contact Temperature Measurement
Lata, Miroslav ; Janečka, Jan (referee) ; Vdoleček, František (advisor)
The object of this bachelor thesis was to create a study of development non-contact temperature measurement and show methods of measurement in infra-red radiation area. The beginning of this work is focused on major notions and definitions necessary to introduce non-contact temperature measurement topic. Other interest of this work was to mention possible error rate of measurement, it’s reasons then name some ways of calibration of a measuring equipment with it’s reasons too. Last part of this thesis was focused on a practical using of these measuring devices.
CFD software calibration
Gego, Tomáš ; Zima, Martin (referee) ; Popela, Robert (advisor)
The objective of this thesis was to calibrate a CFD software for use on a Formula Student race car. The calibration is performed by comparing the experimental data from the measurement of a single element wing in a wind tunnel with the same case replicated in a CFD software, for which the optimization of settings of the meshing and solver is performed. The result is an evaluation of deviations of CFD by assessing aerodynamic characteristics such as downforce, drag, pressure distribution, separation and wake in freestream and ground effect. The results are processed into a graphical and text form for future use in the design of aerodynamic components.
Calibration and linearization of an RTD sensor
Hucl, Václav ; Šedivá, Soňa (referee) ; Beneš, Petr (advisor)
First part of this work is focused on the description exist method of analogue and digital calibration and linearization static parameters resistance sensors. Second part deal with concrete problem linearization thermistor NTC by multivibrator compound of two transistors same polarity and multivibrator, where active element is operational amplifier. Last part of bachelor work is devoted digital linearization based on curve fitting and linearization based on piecewise-linear interpolation, their using with thermistor NTC and comparison their attributes.

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