845 research outputs found
Automotive plastics with increased scratch resistance
Cílem této bakalářské práce bylo zkoumání změn mechanických a reologických vlastností nanokompozitů na bázi PMMA, kde plnivem byly různé typy pyrogenní siliky (různý měrný povrch a výrobce). Bakalářská práce se v teoretické části zaměřuje na současný stav výzkumu, přípravy a vlastností polymerních nanokompozitů. Pro přípravu nanokompozitů byla zvolena rozpouštěcí metoda, kde do rozpuštěného PMMA byla zamíchána silika. Mechanické vlastnosti v tahu byly měřeny pod Tg, zatímco nad Tg byla měřena viskoelastická odezva (reometr). Plnivo na modul pružnosti pod Tg nemělo výraznější vliv, ale nad Tg (180 °C) jak elastický tak ztrátový modul s rostoucím obsahem siliky a se zvyšující se frekvencí (0,1–100 Hz) rostl. U vzorků s obsahem 1 % se ukázalo, že významnou roli hraje velikost částic a měrný povrch siliky. Nejvíce modul pružnosti PMMA, statický a dynamický, zvýšila silika M-5 o objemovém podílu 1%. Silika však s rostoucím množstvím způsobila významný pokles pevnosti a tažnosti.The aim of this bachelor thesis was the investigation of changes of mechanical and rheological properties of nanocomposites based on PMMA, where filler was fumed silica of four types (different surface area and producer). The thesis focuses on the theoretical part of the current state of research, preparation and properties of nanocomposites. The solvent method was chosen for the preparation of nanocomposites, where silica was mixed with dissolved PMMA. Tensile mechanical properties were measured below Tg, while viscoelastic response was measured above Tg. Silica had not significant influence on the modulus below Tg, but above Tg (180 °C) both modulus, storage and loss, have increased with increasing silica content and with increasing frequency (0,1–100 Hz). The particle size and surface area of silica in a content of 1 % influenced storage modulus of nanocomposites more with respect to the content of 2 %. For samples containing 1 % showed that the significant role played particle size and surface area of silica. The greatest increase of storage and loss modulus of PMMA was reached for silica M-5 in content 1 %. All type of silica decreased tensile strength and strain with increasing silica content in the same way.
Link robots
Bakalářská práce se zaobírá konfiguraci článkových robotů. Je rozdělena do tří části. První část vykládá o robotech, jejich rozdělení a zařazený článkových robotů do tohohle rozdělení. V druhé části řeší problematiku konstrukce jednoho článku a konfigurace celého robota. Řeší také pracovní prostor, polohu koncového bodu a tvorbu modelu. Třetí část pojednává o řídicích systémech, pohonech a senzorech.The bachelor thesis deals with the configuration of the link robots. It is divided into three parts. The first part interprets the robots, their division and ranked link robots into this division. The second part addresses the issue of the single cell structure and configuration of the whole robot. It also addresses workspace,location of endpoint and create a model. The third section discusses control systems, actuators and sensors.
The Construction of Climate Justice Imaginaries through Resistance in the Czech Republic and Poland
The chapter provide an overview of disruptive and constructive aspects of resistance during climate camps organised in the Czech Republic and Poland. To do so, it first briefly describes the importance of coal for energy production in these countries. Later it elaborates on the regional characteristics of extraction and energy policy in both states, as well as previous public mobilisations against coal. The empirical part is then divided into two sections. In the first, it provides an overview of disruptive elements of the resistance, conducted against the power that controls the use of lignite reserves. In the second, it focuses on the aspects and conditions through and in which the movement creates a space for new, counter-hegemonic imaginaries
Human Values for a Sustainable Future from the Czech and Slovak Perspective
Ľudské hodnoty zlučiteľné s udržateľným spôsobom života sú súborom hodnôt, ktorých uplatňovanie podporuje posun k udržateľnej budúcnosti. Tieto hodnoty nie sú úplne nové a nesúvisia s myšlienkou „sociálneho inžinierstva“. Práve naopak. Tvoria jadro spoločného dedičstva ľudstva od najstarších náboženstiev a kultúr až po súčasnosť. Ľudské hodnoty a environmentálna etika mali mimoriadny význam počas prvej celoeurópskej konferencie ministrov životného prostredia na zámku Dobříš pri Prahe (1991). Túto konferenciu inicioval Josef Vavroušek: bývalý československý minister životného prostredia. Vzhľadom na túto skutočnosť sa Josef Vavroušek zvykne nazývať otcom procesu „Životné prostredie pre Európu“. Tento článok je venovaný jeho pamiatke.Human values compatible with a sustainable way of living are a set of values, the implementation of which promote the shift towards sustainable future. These values are not completely new and are not related to the idea of “social engineering”. Just opposite. They create the core of the common heritage of Mankind, since the oldest religious and cultures until today. Human values and environmental ethics were of particular importance during the first Pan-European Environmental Ministers Conference at Dobříš Castle near Prague (1991). This conference was initiated by Josef Vavroušek: former Czechoslovak Minister of the Environment. Due to this fact, Josef Vavroušek used to be called the father of the “Environment for Europe”. This article is dedicated to his memory
Archives and Records
This open access book addresses the protection of privacy and personality rights in public records, records management, historical sources, and archives; and historical and current access to them in a broad international comparative perspective. Considering the question “can archiving pose a security risk to the protection of sensitive data and human rights?”, it analyses data security and presents several significant cases of the misuse of sensitive personal data, such as census data or medical records. It examines archival inflation and the minimisation and reduction of data in public records and archives, including data anonymisation and pseudonymisation, and the risks of deanonymisation and reidentification of persons. The book looks at post-mortem privacy protection, the relationship of the right to know and the right to be forgotten and introduces a specific model of four categories of the right to be forgotten. In its conclusion, the book presents a set of recommendations for archives and records management
Archives and Records
This open access book addresses the protection of privacy and personality rights in public records, records management, historical sources, and archives; and historical and current access to them in a broad international comparative perspective. Considering the question “can archiving pose a security risk to the protection of sensitive data and human rights?”, it analyses data security and presents several significant cases of the misuse of sensitive personal data, such as census data or medical records. It examines archival inflation and the minimisation and reduction of data in public records and archives, including data anonymisation and pseudonymisation, and the risks of deanonymisation and reidentification of persons. The book looks at post-mortem privacy protection, the relationship of the right to know and the right to be forgotten and introduces a specific model of four categories of the right to be forgotten. In its conclusion, the book presents a set of recommendations for archives and records management
Safety and Fire Protection of Firefighters during Excavations
Uvedený článok rieši závažnú problematiku bezpečnosti a ochrany zdravia zasahujúcich hasičov vo výkopoch. Každoročne sa stretávame s udalosťami, kde sa nedodržujú stavebné postupy a hlavne bezpečnosť a ochrana zdravia pri práci vo výkopoch.
Pri takýchto zásahoch dochádza k priamemu ohrozeniu zasahujúcich hasičov. Preto je potrebné týmto rizikám predchádzať dodržiavaním technológie záchranných prác a bezpečnosti a ochrane zdravia pri práci.
Ďalej v článku sa rieši rozdelenie a druhy pomoci, možnosti použitia technických prostriedkov a technologických postupov zásahových zložiek pri zásahoch vo výkopoch.This article tackles the serious issues of health and safety of firefighters in the excavations. Every year, we encounter events where building practices and, in particular, occupational health and safety at work are not abnormal.
Such interventions are directly threatened by incendiary fi refi ghters. Therefore, these risks must be avoided by adhering to rescue and occupational safety and health protection.
Further, the article deals with the distribution and types of assistance, the possibilities of using technical means and technological procedures of the intervention components during the excavation interventions
Investigations of cutting power versus clearance of a circular saw blade over the workpiece and feed speed
This paper presents the results of experimental measurement of cutting power in sawing spruce wood (soft wood) by circular saw as a function of clearance and feed speed. Two kinds of circular saw blades made by the company Pilana (CZ) were used for the experiment. The measurement was carried out on the test stand designed at the Department of Woodworking of the Technical University in Zvolen. The results have shown that the feed speed proved to be the most significant factor having impact on energy demand in the process of cutting, the second most significant factor was the clearance of circular saw over the workpiece, while the saw blade type (with the same geometry) had the lowest impact on the cutting power
Measuring income inequalities beyond the Gini coefficient
Growing interest in the analysis of interrelationships between income distribution and economic growth has recently stimulated new theoretical and empirical research. Measures such as the head-count ratio for the poverty index or the widely used Gini coefficient are aggregated indicators describing the general extent of inequality without deeper insights into income distribution among households. To derive an indicator accounting for income distribution among income groups, we propose a new approach based on an output oriented DEA model where the input value is unitized to 1 for each country and weights restrictions imposed so as to favour a higher income share in the lower quantiles. We demonstrate the merits of this approach on the quintile income breakdown data of 29 European countries. Prioritizing lower income groups' welfare, countries such as Slovenia and Slovakia can be equally favoured by the new proposed indicator while being assessed differently by the Gini index. An intertemporal analysis reveals a slight deterioration of income distribution in the majority of 29 European countries over the period of 2007–2016 in a Rawlsian sense
- …