Energy prices are increasing all the time. Further worldwide supplies of fossil fuels are decreased. These supplies will be exhausted in the future. Therefore, it is necessary to find new energy sources. The direct transformation of solar energy into electrical energy through the use of photovoltaic cells is one of the possibilities. The aim of this paper is to illustrate the working principle of the photovoltaic system FVS 2001E that is located on an external wall of a building of Tomas Bata University in Zlín.
The paper deals with a model for water freezing in a deformable elastoplastic container. The mathematical problem consists of a system of one parabolic equation for temperature, one integrodifferential equation with a hysteresis operator for local volume increment, and one differential inclusion for the water content. The problem is shown to admit a unique global uniformly bounded weak solution.
Energetická soběstačnost patří podle Světové obchodní organizace mezi desítku výzev, jimž budeme čelit v následujících desetiletích. Současné dominantní zdroje energie nejsou trvalým řešením, a tak musíme nejen hledat zdroje nové, ale přitom i zdokonalovat její přeměnu a vyřešit skladování. Právě to je jedním z úkolů Strategie AV21. and Luděk Svoboda.
Sunlight is the source of energy for most of the processes on the Earth‘s surface and it represents also the ulitmate renewable energy source for human civilisation. The invention of photovoltaic solar cells and their development to the present highly sophisticated forms represent a story worth telling. The history of photovoltaics contains surprising and dramatic moments as well as steady progress, on a par with the rise of microelectronics. Further, there may still be some surprising new paths, similar to the recent development of hybrid perovskite solar cells., Antonín Fejfar, Martin Ledinský., and Obsahuje seznam literatury
This contribution deals with a new view of using a turbine in the exhaust system of the vehicle. Instead of a classic connection with blowers there is a connection with an alternator and outline of following possibility to use gained electrical energy from exhaust fumes of a combustion engine. and Příspěvek pojednává o novém pohledu na využití turbíny ve výfukové soustavě vozidla. Místo klasického spojení s dmychadlem jde o spojení s alternátorem a o nastínění navazujících možností využití získané elektrické energie z výfukových plynů spalovacího motoru.
Palivem průmyslové revoluce bylo do značné míry uhlí. Jak industrializace pokračovala, vytvořil se, především na Západě, úzký vztah mezi zvyšováním poptávky po energii a ekonomickým růstem. Poptávka po elektřině rostla dokonce ještě strměji než poptávka po primární energii, a tento stav přetrval až do tohoto století. S rozvojem dopravy, pozemní i letecké, neustále stoupala poptávka po benzinu. Rychlý růst v dopravním sektoru souvisel s rostoucím počtem aut, kterých je v současnosti 600 milionů a předpokládá se, že do roku 2020 jejich počet stoupne pětinásobně, zhruba na 3 miliardy. Ještě výraznější byl růst objemu letecké přepravy a tento trend bude pokračovat. Existuje tedy obrovský potenciál budoucího růstu poptávky po energii. and Ian Fells ; přeložil Pavel Svoboda.
Coal measure strata are composed of multiple interbedding strata with different hardnesses. A sudden release of energy that was stored in surrounding rocks of tunnels may induce a rock burst; however, the specific strata in which the energy is accumulated cannot be accurately determined, thereby leading to ineffective prevention and management techniques for rock bursts. To address this problem, this study conducted axial loading tests on three different types of rock specimens (coal, gritstone and fine sandstone) and their composite specimens, and ascertained the energy accumulation rules of various components of the composites prior to a buckling failure. According to the results: for the coal-bearing binary composite specimens, the energy accumulated in coal occupied 88.5 %, 79.0 %, 71.4% and 79.6 % of the total energy accumulated in the specimens respectively; for the binary composite specimens composed of gritstone and fine sandstone, the energy accumulated in gritstone took up 61.2 % and 76.5 % of the total energy accumulated in the specimens respectively; and for the ternary composites, the energy accumulated in the coal occupied 79.8 %, 74.0 % and 76.3 % of the total energy accumulated in the specimens respectively, followed by the energy accumulated in the gritstone (12.1 %, 22.0 % and 18.8 %), and finally by the energy accumulated in the fine sandstone (only 8.1 %, 4.0 % and 4.9 %). Accordingly, in the composite rock strata, a small amount of energy was stored, and energy accumulation was more difficult in competent rock with large elastic moduli, while non-competent strata with small elastic moduli were preferable with regard to energy storage and accumulation. It can thus be concluded that the energy in coal-rock composites was accumulated mainly in non-competent strata, i.e., non-competent strata were key energy strata; additionally, the greater the difference in the hardness of the various components, the stronger the impact effect on the composite specimen.