Rostislav Šulc

Mathematical Model of the Painting Robot

The main objective of the research work was to construct a techno-mathematical model of the robotic arm for conducting painting work, which would streamline the speed and quality of work performed with respect to material savings. For research we chose a robotic arm that is commonly used in industrial production, and adapted it for our conditions. The mathematical model is designed to find the optimal trajectory for moving the robotic arm, where the emphasis is placed on minimizing the path length of motion of the robot ́s endpoint, thus reducing overall energy consumption for the building work. First, the optimal mathematical modeling method was chosen, it was selected according to conditions and parameters of the robotic arm. Thanks to the applied method we picked the software that helped to create the algorithm. Subsequently, a computer simulation and calculation of the optimal motion using a combination of virtual circles, sine and cosine theorem, was done. Further, we checked all relevant angles and calculation of the robotic arm rotation in space for each admissible variant. The last step was the selection of the optimal trajectory of the robotic arm in 3D space.

Optimization of the Composition of the Binder Based on CFBC Fly Ash

This paper is bound to previous research of materials based on fly ash. The main objective was to design an optimal ternary (three-component) binder based on fly ash from Circulating fluidized Bed Combustion (CFBC). The design of the binder is based on the optimization of individual components. Main components of the binder are CFBC fly ash, high-temperature fly ash and slaked lime. The binder was progressively designed and optimized. The strength characteristics of the various binders were measured, evaluated and the results were inserted into computer programs Surfer 8 and Grapher 8 from which ternary diagrams with strength maps were created. The best binder mixture were selected from the optimization process.

Chloride Resistance of Nanoparticle Repaired Concrete Measured by Accelerated Tests

This paper describes results of experimental investigation of chloride ion penetration in concrete. Chloride concentration have been studied in accelerated conditions. Part of concrete samples were treated with colloidal nanosilica solution to increase their resistance to further chloride penetration. Measurement of chloride profiles was performed and compared on samples subjected to accelerated electrical migration tests lasting for a few days. The chloride ion profile in samples was determined in layers of 5 mm thickness up to a total profile thickness of 45 mm. The developed chloride concentrations reached values found after several years of exposure in natural conditions. It was found that the resistance to chloride penetration is substantially improved by nanosilica injection and the resistance to chloride penetration is increased by 60%.

Influence of Milling on some Chemical Properties and Reactivity of CFBC Fly Ash

This paper describes influence of milling on chemical properties of fly ash from Circulating fluidized Bed Combustion (CFBC). Specific properties of fly ash was determined using calorimetric measurement. It was determined heat properties and total content of calcium oxide CaO. The following methods of measurement were also performed: granulometric measurement and chemical analysis. The ash properties of non-milled and milled ashes were also described and evaluated and the ash reactivity was compared.

Nanoparticles in Concrete: Application in Fresh and Hardened State

The paper summarizes utilization of nanoparticles (NP) in concrete for enhancing its mechanical, transport or other properties. The first part is devoted to review of NPs used in fresh concrete mixtures that have been reported previously in the literature while the second part shows original results from utilization of nanoparticles as healing agents for reparing of existing concrete structures. In the second case, nanoparticles are delivered to concrete via electrokinetic principle by using their surface charge provided in colloidal solutions. Particles are transported in the pore liquid of concrete due to electric field applied between the concrete surface and steel reinforcement. In this way, distressed concrete can be repaired, cracks sealed and risk of corrosion diminished. The injection of NPs can be complemented with extraction of chlorides that are the main deteriorating chemicals in reinforced concrete structures. Finally, the paper shows a framework developed for the electrokinetic transport of ionic species in concrete applied to chloride extraction from concrete and how it can be modified also for transport of nanoparticles.

CFBC Bottom Ash as Fine Active Filler for High Performance Composite Building Materials

This article presents the results of the bottom ash from Circulating fluidized Bed Combustion (CFBC). Ashes were modified by grinding in their physical parameters. For this treatment was used the tumbling ball mill at CTU in Prague. In this case were used bottom ashes from Ledvice power plant. Samples of bottom ash were milled in specific amounts and grinding times. The modified samples were tested for the effect of amount of bottom ash in the mill and grinding time on its granulometry. For this testing was used laser diffraction method with particle size analyzer. Milling seems to be great way to get material with better physical and mechanical properties. The reason for this experiment was to better understand behaviour of bottom ash during grinding and made fine filler with specific features for composite building material with high strength.

Modelling of Industrial Robotic Brick System

The paper will describe a design of functional model of a bricklaying industrial robot that is able to technically implement the complete process of bricklaying. The system will be created at a reduced scale and will be able to brick object. The robotic system for bricklaying will use special developed software which will convert the necessary data of mathematical model from BIM environment to format KUKA for industrial robots KRC4 and make optimal design of movements of the robotic arm. As a result will be developed: a functional model of the robotic bricklaying system including technology (de-palletizing, motion control, cutting and gluing bricks on the bond); Software for data migration (IFC -> KRC4), technical equipment (grip, applying mortar / glue, cutting bricks, control systems); control system including optimization processes (energy, time, material consumption).

Rheological Characteristics of Alkali Activated Fly-Ash Concrete Mixtures

This paper describes rheological characteristics of concrete mixtures based on alkali-activated fly ash. There are shown relationships between workability of fly-ash fresh concrete mixtures and water–fly-ash ratio in fresh alkali-activated concrete. In addition, there is described relationship between workability in fresh mixture on compressive strength of alkali-activated concrete.

Chemical Properties and Reactivity of CFBC Fly Ash

This paper describes chemical properties of fly ash from Circulating fluidized Bed Combustion (CFBC). There are shown thermal properties of fly ash using calorimetric measurement and the total content of calcium oxide CaO was determined. This paper describes the methods of measurement for determining these properties including granulometric measurement and chemical analysis. Also there were described and evaluated properties of fly ash and the reactivity of the fly ash was compared.

Grindability of CFBC Fly Ash and High Temperature Fly Ash

This article presents the results of fly ash from Circulating fluidized Bed Combustion (CFBC) and high temperature fly ash (defined in EN 450-1) with modified physical parameters by grinding. For this treatment was used the mechanical mill. In this case were used two fly ashes. The first sample was from Tisová power plant (CFBC fly ash) and the second one from Počerady power plant (high temperature fly ash). The modified samples were tested for the effect of grinding time on its grindability and granulometry. For testing of samples was used laser diffraction with particle size analyzer and the grindability was determined. The reason for this step was found more stable and better material which achieves better physical and mechanical properties. The first step is mechanical treatment of fly ash’s granule.