TESTING OF GLUED JOINTS ON PLASTIC PARTS MANUFACTURED USING FFF TECHNOLOGY

The article focuses on the testing of glued joints of plastic parts manufactured by 3D rapid prototyping, using the Fused Filament Fabrication technology. The first part of the article describes the suitability of using a glued joint. Then follows a brief description of the plastic materials used for the manufacturing of the testing samples. The materials include not only the common types, such as Polylactide, Polyethylene Terephthalate, Acrylonitrile Butadiene Styrene, but also Thermoplastic Polyurethane, which has a high elasticity and is usually described as a flexible material. The main section of the article deals with the testing of glued joints on a tensometric machine, which produces stress-strain curves. The shear strength of the joints is evaluated. For each material, multiple samples are prepared with different orientation of individual layers created by the 3D printing process. The impact of the orientation of the layers on the resulting strength of the glued joint is also evaluated. The final section of the article presents comparison and evaluation of the results –analyses of cracks, the impact of the orientation of the layers and the impact of individual materials. The experiment proved the independence of the orientation of the layers on the strength of the glued joint. It was also found out during the experiment that the use of a common adhesive on a flexible material was unsuitable

Inhibition of acetylcholinesterase in different structures of the rat brain following soman intoxication pretreated with huperzine A

Acetylcholinesterase (AChE) activities in different brain parts were determined quantitatively in rats treated with huperzine A, soman, and huperzine A followed by soman, using histochemical and biochemical methods. Following soman intoxication ( 1.2 x LD50, i.m.), AChE activity was decreased to 30-80% of control values depending on the brain structure. The most sensitive area was the frontal cortex and the most relatively resistant was ncl.ruber. Huperzine A treatment only caused a change in AChE activity varying from 70 to 100% of control values. In rats pretreated with huperzine A and intoxicated with soman, AChE activity was significantly higher than that observed after soman. In these animals, survival of rats pretreated with huperzine was observed while the mortality of unpretreated animals was near to 80%. The results suggest that huperzine A is good candidate for further study for clinical use as a prophylactic drug against nerve agent poisoning

Economic position of selected countries of Central Asia in the world economy (Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan)

Tato práce má za úkol analyzovat ekonomické postavení vybraných států (Kyrgyzstán, Tádžikistán, Turkmenistán, Uzbekistán) s ohledem na jeho relevantní příčiny, vliv společenských struktur a politických aktérů a identifikovat potenciál dalšího rozvoje oblasti. Pro tyto účely poskytuje základní informace o moderní historii regionu a socioekonomické charakteristice zemí s problematikou náboženství a státní správy. Dále podrobněji prezentuje vývoj po rozpadu Sovětského svazu v politické a zejména ekonomické oblasti, aby určila současnou pozici států ve světovém hospodářství, odvíjející se též od zapojení do integračních uskupení a bilaterálních vztahů s dalšími aktéry, kde se na klíčových pozicích nacházejí Čína, Rusko a USA, EU naopak doposud plně nevyužívá svých možností.This thesis aims to analyze the economic status of selected countries (Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan) with respect to the relevant causes, the impact of social structures and political actors, and to identify potential for further development in the area. In order to do so, it provides basic information about the modern history of the region and socio-economic characteristics of the countries mentioning the problems of religion and good governance. Furthermore, the thesis presents in detail the transformation of the region in the political and especially in the economic area after the dissolution of the Soviet Union. To determine the current position of these states in the global economy, it reflects the engagement in various integration groupings and bilateral relations with the key actors, such as China, Russia and US, while the EU has not yet made full use of its capabilities

Polito-economic situation in the Caucasus

This thesis is supposed to offer an overview of the political and economic situation in the Caucasus. Its chapters include information about basic characteristics of the region, brief history (mostly the 20th century), the situation in Armenia, Azerbaijan, Georgia and seven russian autonomous republics nowadays, and the conflicts between caucasian nations, ethnic groups and different religions. As a result, it can be considered as a certain summary of the facts about the Caucasus

The Influence of Oxime Selection on the Efficacy of Antidotal Treatment of Soman-Poisoned Rats

1. The influence of some acetylcholinesterase reactivators (HI-6, obidoxime, pralidoxime) on the efficacy of antidotal treatment to eliminate soman-induced disturbance of respiration and circulation and to protect experimental animals poisoned with supralethal dose of soman (1.5 × LD50) was investigated in a rat model with on-line monitoring of respiratory and circulatory parameters. 2. Obidoxime or pralidoxime in combination with atropine were insufficient to enable soman-poisoned rats to survive for 2 hours when given 1 minute after the administration of soman. 3. On the other hand, the ability of the oxime HI-6 in combination with atropine to prevent soman-induced alteration of respiration and circulation was significantly higher. Some rats treated with HI-6 in combination with atropine were fully protected against the lethal toxic effects of soman within 2 hours following soman administration. 4. Our findings confirm that the oxime HI-6 seems to be a much more suitable and efficacious acetylcholinesterase reactivator for the antidotal treatment of severe acute soman-induced poisoning than currently used obidoxime or pralidoxime

EAN 2020

The Experimental Stress Analysis 2020 (“Experimentální Analýza Napětí 2020” in Czech, EAN2020) is organized with the support of Czech Society for Mechanics, Expert Group of Experimental Mechanics. The 58th continuation of the series of international conferences Experimental Stress Analysis, taking place usually in Czech Republic and Slovakia, held in online, Czech Republic, 19–22 October 2020, under the patronage of the dean of Faculty of Mechanical Engineering VŠB-Technical University of Ostrava, prof. Ing. Robert Čep, Ph.D., on the occasion of the 70th anniversary of FME VSB-TUO.Ostrav

Strength analysis and optimization of welding robot mechanism in emergency stop state

The contribution deals with the strength analysis and optimization of the welding robot mechanism in emergency stop state. The common operational positioning of the welding robot is characterized by smooth course of speeds in the time. The resulting load does not differ significantly from the static loading. However the safety requirements given by the norm require the ability of emergency stop function. Since the course of speed in time is rather steep the higher values of acceleration and thus higher excitation force is expected. The dynamical simulation performed describes the response of the robot mechanism in the form of stress course in time, quantifies the peak values of the stress caused by the dynamical component of loading and highlights the potential risks associated with this phenomenon