A reflection of the coronavirus crisis compared to the regular activities of the scout troop.

Katedra pedagogikyFaculty of EducationPedagogická fakult

Modelling and simulation of robotic applications

Cílem této diplomové práce je provést rešerši v oblasti Open Source softwaru pro simulaci autonomních robotů. V úvodu je provedena rešerše vybraných robotických simulátorů. V první části této práce je seznámení se s robotickým simulátorem Gazebo a robotickým frameworkem ROS. Druhá část této práce se zabývá simulováním a následnou implementací vybranné robotické úlohy prostřednictvím simulátoru Gazeba a frameworku ROS.The aim of this master thesis is to make research of Open Source software, which are used for simulation autonomous robots. At the begining is performed research of selected robotic simulators. In the first part of this work is to get familiar with robotic simulator Gazebo and robotic framework ROS. The second part of this work deals with simulating and subsequent implementation of choosen robotic tasks through the simulator Gazebo and the ROS framework.

Software for the simulation of autonomous robot

Cílem této bakalářské práce je provést rešerši v oblasti SW pro simulaci autonomních robotů. V úvodu jsou vysvětleny obecné pojmy, týkající se robotické simulace. Dále jsou obecně vysvětleny výhody použití robotických simulátorů. V první části rešerše jsou popsány vybrané robotické simulátory. Druhá část rešerše spočívá v porovnání jednotlivých robotických simulátorů z hlediska vhodnosti pro simulaci robotických úloh. Po porovnání je vybrán nejvhodnější robotický simulátor, ve kterém je následně demonstrována robotická ukázka.Objective of this bachelor work is to make research of SW, which are used for simulation of autonomous robots. At the beginning I explain general concepts of robotic simulation. And I also explain advantages of usage of robotic simulators. In the first part of my research are described some chosen robotic simulators. The second part of my research compares robotic simulators, which is more suitable for simulations of robotic operations. In the end of my research the most suitable simulator is taken and used for simple robotic demonstration.

New filler for lightweight concrete

V příspěvku jsou prezentovány výsledky experimentálního výzkumu zabývajícího se problematikou využití recyklované tvrdé polyuretanové pěny po ukončení životního cyklu o objemové hmotnosti 30 - 35 kg.m-3 jako nového plniva do lehkých betonů. Cílem bylo navrhnout optimální recepturu, s optimálním poměrem jednotlivých složek betonové směsi. U navržených experimentálních záměsí, byly sledovány následující vlastnosti: konzistence čerstvého betonu, objemová hmotnost čerstvého betonu, objemová hmotnost ztvrdlého betonu, krychelná a hranolová pevnost v tlaku.The article presents the results of an experimental research dealing with the utilisation of recycled rigid polyurethane foam after the end of its life cycle, with the bulk density of 30-35 kg.m-3, used as new filler for lightweight concrete. The objective of the research was to design an optimal recipe, with an optimal ratio of the individual components of the concrete mixture. The following properties of the prepared experimental mixtures were monitored: consistency of the concrete mixture, the bulk density of fresh concrete mixture, bulk density of hardened concrete, cube and prism compressive strength

Wideband transimpedance photodiode amplifier

Tato práce se zabývá návrhem transimpedančního zesilovače s velkým zesílením. Jsou zde popsány různé principy polovodičových snímačů optického signálu. Dále se zde nachází porovnání různých způsobu převodu fotoproudu na elektrické napětí. Zabývá se také návrhem vhodného zpětnovazebního kompenzačního kondenzátoru z pohledu stability v zapojení jako transimpedanční zesilovač. Zkoumá se vliv nenulových proudů tekoucích do vstupu operačního zesilovače na funkčnost obvodu a kompenzaci výstupního offsetu. Součástí práce je simulace, která potvrzuje vypočtené hodnoty. Práce se dále věnuje realizaci přijímače a způsobu korektního měření mezního kmitočtu.This thesis deals with the design of transimpedance amplifier with high gain. There are described different principles of semiconductor sensors of optical signal. There is also a comparison of different methods of converting the photocurrent to voltage. It also discusses the design of an appropriate feedback capacitor in terms of stability in participation as a transimpedance amplifier. It examines the impact of non-zero currents flowing to the input operational amplifier circuit functionality and output offset compensation. Part of the thesis is a simulation that confirms the calculated values. The thesis also deals with the implementation of the receiver and the method of correct measurement of the cut-off frequency.

Poliuretanska pjena kao agregat za toplinske izolacijske žbuke i laki beton

The contribution describes the use of polyurethane foam after the end of its life cycle as an aggregate both for thermal insulating mortars for various wall surfaces and for lightweight concrete. The structure and the physical and mechanical properties of thermal insulating mortar are described here. The verification of application of thermal insulating polyurethane mortar in the thickness of 50 ÷ 70 mm to a reference building, where external walls were insulated, is provided further. The second important area dealt with in this contribution is that of lightweight concrete, for which polyurethane foam of grain size of 0,125 ÷ 6 mm is used as an aggregate. The physical and mechanical properties of polyurethane concrete of various densities and an example of its prefabrication are presented.Prilog opisuje uporabu poliuretanske pjene nakon završetka njezinog životnog ciklusa kao agregata i za toplinske izolacije žbuke za različite zidne površine i za laki beton. Ovdje su opisane struktura i fizikalno-mehanička svojstva toplinske izolacijske žbuke. Nadalje se daje provjera primjene toplinske izolacijske poliuretanske žbuke u debljini 50 do 70 mm na referentnoj zgradi, kod koje su vanjski zidovi izolirani. Drugo važno područje kojim se bavi ovaj prilog je da se poliuretanska pjena veličine zrna od 0,125 do 6 mm koristi kao agregat kod lakog betona. Prikazana su fizikalna i mehanička svojstava betona od poliuretana različitih gustoća i primjer njegove prerade.Web of Science19367266

Parametric study of the energy potential of a building’s envelope with integrated energy-active elements

Building structures with integrated energy-active elements (BSIEAE) present a progressive alternative for building construction with multifunctional energy functions. The aim was to determine the energy potential of a building envelope with integrated energy-active elements in the function of direct-heating, semi-accumulation and accumulation of large-area radiant heating. The research methodology consists in an analysis of building structures with energy-active elements, creation of mathematical-physical models based on the simplified definition of heat and mass transfer in radiant large-area heating, and a parametric study of the energy potential of individual variants of technical solutions. The results indicate that the increase in heat loss due to the location of the tubes in the structure closer to the exterior is negligible for Variant II, semi-accumulation heating, and Variant III, accumulation heating, as compared to Variant I, direct heating, it is below 1 % of the total delivered heat flux. The direct heat flux to the heated room is 89.17 %, 73.36 %, and 58.46 % of the total heat flux for Variant I, Variant II and Variant III, respectively. For Variant II and Variant III, the heat storage accounts for 14.84 %, and 29.86 % of the total heat flux, respectively. Variants II and III appear to be promising in terms of heat/cool accumulation with an assumption of lower energy demand (at least 10 %) than for low inertia walls. We plan to extend these simplified parametric studies with dynamic computer simulations to optimise the design and composition of the panels with integrated energy-active elements

Thin high-strength zirconia tapes with extreme flexibility

The yttria stabilized zirconia ceramics (Y-TZP) are known for their high fracture toughness and high strength. Due to their excellent mechanical properties, the thin zirconia tapes can possess extraordinary behavior - extreme flexibility. In the present work, we introduce an adaptation of gel-tape casting method for the preparation of thin, high-strength zirconia tapes from water-based suspensions. Fine ceramic powder with a particle size of around 100 nm was used. The negative effect of sodium ions on the strength and toughness of sintered ceramic samples was revealed and explained. Ceramic tapes with a thickness of 190 mu m with as-sintered surfaces reached a characteristic biaxial strength of 1805 MPa. The huge elastic deformation of ceramic tapes was demonstrated in a 3- point bend test, and a bending radius of 25 mm for a 75 mu m thick tape was reached

Machinability and properties of zirconia ceramics prepared by gelcasting method

The machinability of newly developed zirconia ceramics for computer numerically controlled milling (CNC) was investigated. The zirconia blanks were prepared by the gelcasting method and tested in the green and two pre-sintered states. All blanks exhibited uniform sintering shrinkage in all directions. The blanks were investigated from the viewpoint of surface milling roughness, quality of milled edges and sharp tips, and machinability of thin structures. The best milling results were obtained for the blanks pre-sintered at 900?C/1?h. Mechanical properties of zirconia blanks, such as biaxial flexural strength, microhardness, indentation elastic modulus, and fracture toughness were determined in the green and pre-sintered states (900 and 1100?C/1?h) and the correlation with the milling results was discussed. The biaxial strength tests of sintered discs showed the advantage of optimised surface milling over conventional polishing