National Repository of Grey Literature 60 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Heterogeneous bipolar membrane and the influence of composition on its properties
Kvasničková, Lucie ; Válek, Robert (referee) ; Neděla, David (advisor)
This work is focused on the preparation of heterogeneous bipolar membranes and studies the influence of different composition on mechanical and physical properties. The main feature of this approach is optimalization of composition following gained data. Theoretical part contains new piece of knowledge in the field of heterogeneous bipolar membranes. Experimental part engages preparation of bipolar ion-exchange membranes on one face cation-selective and on the other one anion-selective. In this case are used variant types of polyethylene.
Strengthening steel beams using reinforcement based on FRP
Bláha, Tomáš ; Melcher, Jindřich (referee) ; Karmazínová, Marcela (advisor)
A study of an influence of strengthening steel beams using reinforcement based on FRP on a moment bearing resistance and bending stiffness. Evaluation of the theoretical calculation methods based on the performed experimental verification. Description of the production of carbon fibres and composite materials on the basis of carbon fibres.
Assessment of the effect of origin and the fraction of coarse aggregate for flexibility and durability of structural concrete
Hanuš, Petr ; Žalud, Oldřich (referee) ; Vymazal, Tomáš (advisor)
The bachelor thesis deals with influence of origin and fraction of rough aggregate on the durability and elasticity of structural concrete. As a criterion of durability, the frost resistance of concrete is monitored. In the theoretical part describes the types of aggregates, which are used in structural concretes. In addition, test methods are described to determine the elasticity and durability of concrete according to the test standards valid in the czech republic. In the experimental part of the thesis, seven concretes of the same consistency and strength were designed and mixed, which differed using different types of coarse aggregate. A change in elasticity during freezing cycles was observed
Nonlinear analysis of reinforced concrete foot failure
Dubina, Radek ; Václav,, Veselý (referee) ; Eliáš, Jan (advisor)
Reinforced concrete monolithic feet are one kind of shallow foundation used mainly under column systems. These systems transfer the load from upper floors through columns to the feet and through them to the foundation soil. Interaction between the foot and the foundation soil plays an important role due to the system sensitivity to the uneven settlement. Feet has to resist shear induced by vertical force and bending moment caused by stress in footing bottom. The work is devoted to design of the foot according to European standard Eurocode 2. It is then focused on numerical simulation of foot failure and calculation of the corresponding maximal vertical force in the column using a 3D model with nonlinear material models of subsoil, reinforcement and concrete. The calculations are done in software ATENA 3D for different variants of subsoil, reinforcement and foot shape. Results according to European standard and nonlinear analysis are compared.
Design and construction of the task to the subject PPI
Král, Jiří ; Krejčí, Petr (referee) ; Návrat, Tomáš (advisor)
The bachelor thesis deals with creating of computational model for definition of tensity and deformations of bars system. Then the physical model is made according to the theoretical model. This physical model is used for educational purposes. Next step is measurement of stress and deformation of bars. The final part is focused on eventual variations between theoretical and real model.
Obmedzovanie škodlivej spotreby v Európskej únii pomocou daňových nástrojov
Černáček, Kristián
The diploma thesis is focused on consumption taxes in the European Union, their changes and impacts on limiting harmful consumption. The author of the diploma thesis examines the level and change of consumption tax rates in EU countries, the development of average and median wages, prices of goods of harmful consumption and the costs caused by harmful consumption. The main goal of the diploma thesis is to find out whether it is possible to effectively reduce consumption by increasing tax rates. The secondary goal is to define the amount of consumption taxes in the EU, to find out prices and wages. In the Czech Repub-lic, find out the level of consumption, calculate the elasticity of demand and compare the results with the results of a questionnaire survey. Based on the findings, evaluate the effectiveness of the tax policy and propose measures.
Torsion of beams with a non-circular cross-section
Hablák, Ján ; Majer, Zdeněk (referee) ; Profant, Tomáš (advisor)
The bachelor’s thesis focuses on the issue of torsion of prismatic bar with a non-circular cross-section, its model in various software, calculation and comparison of real measurements with calculated values. The aim of the work is to get acquainted with the basic theoretical knowledge, which will subsequently be applied in the modeling and calculation of specific closed profiles. Individual results are compared in the thesis. Basic concepts and knowledge are explained in the theoretical part. The practical part deals with the calculation of individual cross-sections and practical measurement.
The application of elastic-plastic models in estimating damage zones caused by blasting of deep tunnels
Sysala, Stanislav
The paper deals with the continuous modelling of damage zones caused by excavation of tunnels and boreholes in connection with deep repository of spent nuclear fuel in crystalline rocks. For simplicity, elastic and elastic-plastic modelling approaches based on Mohr-Coulomb or Hoek-Brown failure criteria are presented and compared. For the implementation, proper codes were created in Matlab and Python with innovative elements.
AB INITIO STUDY OF SILVER NANOPARTICLES, GRAIN BOUNDARIES AND THEIR \nQUADRUPLE JUNCTIONS
Polsterová, S. ; Všianská, Monika ; Friák, Martin ; Pizúrová, Naděžda ; Sokovnin, S. ; Šob, Mojmír
Motivated by our experimental research related to silver nanoparticles with various morphologies, we have employed quantum-mechanical calculations to provide our experiments with theoretical insight. We have computed properties of a 181-atom decahedral silver nanoparticle and two types of internal extended defects, -5(210) grain boundaries (GBs) and quadruple junctions (QJs) of these GBs. We have employed a supercell approach with periodic boundary conditions. Regarding the thermodynamic stability of the decahedral nanoparticle, its energy is higher than that of a defect-free face-centered cubic (fcc) Ag by 0.34 eV/atom. As far as the -5(210) GB is concerned, its energy amounts to 0.7 J/m2 and we predict that the studied GBs would locally expand the volume of the lattice. Importantly, the system with GBs is found rather close to the limit of mechanical stability. In particular, the computed value of the shear-related elastic constant C66 is as low as 9.4 GPa with the zero/negative value representing a mechanically unstable system. We thus predict that the -5(210) GBs may be prone to failure due to specific shearing deformation modes. The studied GBs have also the value of Poisson’s ratio for some loading directions close to zero. Next, we compare our results related solely to -5(210) GBs with those of a system where multiple intersecting -5(210) GBs form a network of quadruple junctions. The value of the critical elastic constant C66 is higher in this case, 13 GPa, and the mechanical stability is, therefore, better in the system with QJs.
Modelling ethanol production in simultaneous equations model of global food demand and supply
Kozák, Miroslav ; Janda, Karel (advisor) ; Macháček, Vít (referee)
This thesis conducts an econometric analysis for the relationship between food price and ethanol production. A system of simultaneous equation models for the demand and supply for food are estimated, paying attention to the effect of ethanol production. The two-stage and three-stage least-squares estimation methods are adopted, which explicitly account for endogeneity in the system. Using annual data from 1981 to 2020, it is found that the ethanol production has little economic impact on food price. This may be closely related with inelastic demand and supply with respect to price that have been found in this study, where exogenous shocks such as an increase of ethanol production may have small effects on price. JEL Classification C12, C13, D12 Keywords Ethanol, Endogeneity, Food Price, Elasticity, Si- multaneous Equations Model Title Modelling ethanol production in simultaneous equations model of global food demand and sup- ply Author's e-mail kozakmiroslav92@gmail.com Supervisor's e-mail karel-janda@seznam.cz

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