Browsing by Subject "mathematical modeling"

Now showing 1 - 3 of 3

Access status: Open Access ,
Mathematical modelling of the continuous casting of blooms and beam blanks
(Wydawnictwa AGH, 2021) Gomes, Daniela Fátima; Braga, Bernardo Martins; Tavares, Roberto Parreiras; Bagatini, Maurício Covcevich
Defects and discontinuities generated in continuous casting are directly related to heat transfer during the process and the stresses to which the material is subjected. Knowledge of these phenomena is essential for both process safety and the quality of the final product. The aim of this work is to analyze the thermo-mechanical behavior of blooms and beam blanks during continuous casting. The continuous casting machine considered in this study is used to cast both blooms and beam blanks. The secondary cooling can be divided into cooling zone z0, cooling zone z1, cooling zone z2, and cooling zone z3. For each geometry, there are specific molds, z0, z1, z2 (sprays and support rollers), which need to be replaced when there is a geometry shift. The changing of the cooling segments brings security risks for the operators and reduces the continuous casting availability. Therefore, it is desired to have a common z2 for both blooms and beam blanks to reduce operational risk exposure and increase the machine production rate. For this to be possible, it is necessary to assess the temperature and resistance of the solidified skin, the effects of thermal stresses, ferrostatic pressure, and contact stresses. This work is the first step in this study. A thermo-mechanical model was developed for both geometries. The thermal model was verified by temperature measurement and shell measurements of blackouts. Finally, the results were analyzed and compared.
Access status: Open Access ,
Present metrological standards in mathematical modeling procedures
(2013) Twardowski, Kazimierz; Lewandowska-Śmierzchalska, Joanna; Przybyłowicz, Joanna
In the years 1993-1994 International Organization for Standardization (ISO) introduced to the metrology the fundamental changes of basic character, involving - in addition to the traditional concept of measurement error - the use of new fundamental term of uncertainty of measurement. In consequence, this has led to currently undisputed axiom of metrology, that the measurement result has a form of a section on dimensional axis. These rules of presenting measurable physical values should be reflected in the of practical procedures of mathematical modeling. Presented work relates to this particular problem. It discusses the principles of mathematical modeling together with the assessment of the results. Particular attention was paid to the identification of possible systematic errors (i.e. the load of model) and to estimating the uncertainty of the statistical and deterministic modeling.
Access status: Open Access ,
The art and science of modeling decision-making under severe uncertainty
(2007) Sniedovich, Moshe
For obvious reasons, models for decision-making under severe uncertainty are austere. Simply put, there is precious little to work with under these conditions. This fact highlights the great importance of utilizing in such cases the ingredients of the mathematical model to the fullest extent, which in turn brings under the spotlight the art of mathematical modeling. In this discussion we examine some of the subtle considerations that are called for in the mathematical modeling of decision-making under severe uncertainty in general, and worst-case analysis in particular. As a case study we discuss the lessons learnt on this front from the <i>Info-Gap</i> experience.