Aspects of classification of energy sources in terms of their position in the sector of the economy

The paper deals with the study of problems relating to classification of energy sources, in particular from the perspective of their position in covering of energy needs of country or economic sector. Classification of energy sources is currently often viewed as a set of fixed categories, but taking a closer look and making a deeper analysis can defined a number of criteria that might determine the final importance and position of resources in the context of complex connections. The composition of energy sources was analysed on a sample of nine countries, which was conceived with the intent to cover various kinds of standard and specific types of energy mixes. In the paper, several criteria for assessing the quantitative and qualitative nature of energy sources were defined. Sectoral, temporal, spatial and scale framework for the validity of the assessment were also defined. In the analysis, the attention was focused on the electricity sector and partially on the sector of transport. The results of the analysis indicate that in different conditions, the same energy source or group can be categorised in a different way, which may have a significant impact on the application of legislation in terms of the use of control, support and regulatory instruments. The analysis took into account in particular the aspects, which complement the recently published papers analyzed this complex issue.Web of Science21429728

Assessment of mining activities with respect to the environmental protection

This paper deals with the impact of mining on the environment. Coal mining is still among the most widespread and most intense mining activity, which disturbs the landscape around us bringing regional environmental, economic and aesthetic problems. However, for many countries in the world, including the Czech Republic, deposits of raw materials play an important role, especially for purposes of producing electricity and thermal energy. At the same time, growing emphasis laid on the environmental protection can be observed worldwide. To meet the increasing ecological demands, it is reasonable to consider the most significant aspects of mining activities from the environmental point of view, as well as to consider the possibilities of the abandoned mines utilization as possible waste dumps. Parts of this problem consist in: the monitoring, environmental impacts assessment of exploration and mining activities and waste disposal mining, which may significantly contribute to the environmental protection in the future. Several parameters that can significantly affect the usability of the waste disposal mining, such as geological structure, hydro-geological conditions, material composition and physical and mechanical properties of rocks are discussed in detail in this work. The article also includes a practical example of Environmental Impact Assessment process for the particular activity of OKD stock company, which is the only producer of hard coal (bituminous coal) in the Czech Republic. Its coal is mined in the southern part of the Upper Silesian Coal Basin - in the Ostrava-Karvina coal district. KeywordsWeb of Science221937

Unconventional oil resources exploitation: a review

Unconventional crude oil sources are geographically extensive and include the tar sands of the Province of Alberta in Canada, the heavy oil belt of the Orinoco region of Venezuela and the oil shales of the United States, Brazil, India and Malagasy. High production costs and low oil prices have hitherto inhibited the inclusion of unconventional oil resources in the world oil resource figures. In the last decade, developing production technologies, coupled with the higher market value of oil, convert large quantities of unconventional oil into an effective resource. From the aspect of quantity and technological and economic recoverability are actually the most important tar sands. Tar sands can be recovered via surface mining or in-situ collection techniques. This is an up-stream part of exploitation process. Again, this is more expensive than lifting conventional petroleum, but for example, Canada's Athabasca (Alberta) Tar Sands is one example of unconventional reserve that can be economically recoverable with the largest surface mining machinery on the waste landscape with important local but also global environmental impacts. The similar technology of up-stream process concerns oil shales. The downstream part process of solid unconventional oil is an energetically difficult process of separation and refining with important increasing of additive carbon production and increasing of final product costs. In the region of Central Europe is estimated the mean volume of 168 million barrels of technically recoverable oil and natural gas liquids situated in Ordovician and Silurian age shales in the Polish-Ukrainian Foredeep basin of Poland.Web of Science21325724

Possibilities of application of static investment appraisal methods for optimizing purchase under conditions of mine rescue service

The present article focuses on the importance of making investment decisions and its long-term effect on the economy of companies. It presents a specific investment in the recovery of rescue equipment used for interventions in the irrespirable or deleterious environment on an example of the company HBZS, a.s. The objective is to evaluate the effectiveness of the investment project using static methods in relation to setting an optimal price level for leasing the equipment. The optimization of such setting is examined in terms of the economic lifetime of relevant tangible fixed assets.Předložený článek se zabývá důležitostí investičního rozhodování a jeho dlouhodobým dopadem pro ekonomiku firem. Na příkladě společnosti HBZS, a.s. je představena konkrétní investice do obnovy záchranářské techniky pro zásahy v nedýchatelném či zdraví škodlivém prostředí. Cílem je zhodnocení efektivnosti investičního projektu pomocí statických metod ve vazbě na nastavení optimální cenové hladiny pronájmu daných přístrojů. Optimalizace tohoto nastavení je zkoumána z hlediska ekonomické životnosti daného dlouhodobého hmotného majetku

Vybrané technologie ochlazování prostorově uzavřených požářišť v hlubinných uhelných dolech

In current mining practice, the most often used methods of cooling spatially sealed fire areas are: natural cooling, cooling by nitrogen, cooling by water and inert foam and cooling by combustion product recirculation. The technology of cooling with nitrogen represents two variants - the use of liquid nitrogen or nitrogen gas in the area of closed mine workings. From a technical and safety points of view the application of liquid nitrogen is today considered unsatisfactory, while the use of nitrogen gas seams to be highly safe technology for cooling explosion-proof sealed fire areas. Another possibility for cooling fire areas in deep coal mines is so-called natural cooling, where economical costs are indeed zero, but comparing to cooling processes induced by the application of cooling technologies a longer time period necessary for the natural refrigeration of fire areas causes financial losses.V současné hornické praxi patří mezi nejpoužívanější způsoby ochlazování prostorově uzavřených požářišť přirozené ochlazování, ochlazování dusíkem, ochlazování vodou a inertní pěnou a ochlazování recirkulací požárních zplodin. Technologie ochlazování pomocí dusíku představuje dvě varianty – použití kapalného dusíku nebo plynného dusíku v prostoru uzavřených důlních děl. Z technicko-bezpečnostního hlediska je aplikace kapalného dusíku již dnes považována za nevyhovující, naproti tomu aplikace plynného dusíku se jeví jako vysoce bezpečná technologie ochlazování výbuchuvzdorně prostorově uzavřeného požářiště. Další z možností ochlazování požářišť v hlubinných uhelných dolech představuje tzv. přirozené ochlazování, kdy jsou sice ekonomické náklady nulové, ovšem ve srovnání s ochlazovacími procesy vyvolanými aplikací chladících technologií však delší doba potřebná k přirozené refrigeraci požářiště způsobuje finanční ztráty

Structural and Mechanical Changes of AlMgSi0.5_{0.5} Alloy during Extrusion by ECAP Method

SPD (several plastic deformations) methods make it possible to obtain an ultrafine-grained structure (UFG) in larger volumes of material and thus improve its mechanical properties. The presented work focuses on the structural and mechanical changes of aluminium alloy AlMgSi$_{0.5}$ (EN AW 6060) during processing by repeated extrusion through the ECAP rectangular channel. After a four-pass extrusion, the samples’ microstructures were observed using an optical microscope, where refinement of the material grains was confirmed. Tensile tests determined the extrusion forces and allowed interpretation of the changes in the mechanical properties of the stressed alloy. The grain size was refined from 28.90 μm to 4.63 μm. A significant improvement in the strength of the material (by 45%) and a significant deterioration in ductility (to 60%) immediately after the first extrusion was confirmed. The third pass through the die appeared to be optimal for the chosen deformation path, while after the fourth pass, micro-cracks appeared, significantly reducing the strength of the material. Based on the measurement results, new analytical equations were formulated to predict the magnitude or intensity of the volumetric and shape deformations of the structural grain size and, in particular, the adequate increase in the strength and yield point of the material

Protokol o testování plastického detektoru v poli radionuklidu Cf-252

Získané výsledky ukazují na schopnost plastického scintilátoru oddělovat fotonovou a neutronovou složku záření. Spodní hranice diskriminace je pod 1 MeV a v porovnání se zkušenostmi se scintilátorem stilben lze předpokládat, že dekonvoluce energetického spektra bude možná v energetickém intervalu nad 2 MeV.Získané výsledky ukazují na schopnost plastického scintilátoru oddělovat fotonovou a neutronovou složku záření. Spodní hranice diskriminace je pod 1 MeV a v porovnání se zkušenostmi se scintilátorem stilben lze předpokládat, že dekonvoluce energetického spektra bude možná v energetickém intervalu nad 2 MeV.The results indicate the ability of the plastic scintillator separate neutron and photon radiation component. The lower boundary of discrimination is below 1 MeV and compared with experience with stilbene scintillator can be assumed that the energy spectrum deconvolution will be possible in the energy range above 2 MeV

Manufacturing technology of composite materials-principles of modification of polymer composite materials technology based on polytetrafluoroethylene

The results of the investigations into the technological formation of new wear-resistant polymer composites based on polytetrafluoroethylene (PTFE) filled with disperse synthetic and natural compounds are presented. The efficiency of using PTFE composites reinforced with carbon fibers depends on many factors, which influence the significant improvement of physicomechanical characteristics. The results of this research allow stating that interfacial and surface phenomena of the polymer-solid interface and composition play a decisive role in PTFE composites properties. Fillers hinder the relative movement of the PTFE molecules past one another and, in this way, reduce creep or deformation of the parts, reducing the wear rate of parts used in dynamic applications as well as the coefficient of thermal expansion. The necessary structural parameters of such polymer composites are provided by regimes of process equipment.Web of Science104art. no. 37

POSSIBILITIES OF THE USE OF WORKING SELF-CONTAINED BREATHING APPARATUSES FILTRATING CARBON MONOXIDE IN THE PRACTICE OF MINE RESCUE SERVICES

In the current practice of the Mining Rescue Service of the Czech Republic, since 2005, the insulated overpressure regenerative breathing apparatuses with a closed circuit and supply of medicinal oxygen are used as the backbone working breathing apparatuses. At the end of the year 2010, the compressed-air breathing apparatuses were introduced into the practice of the Mining Rescue Service of the Czech Republic, which, in precisely defined types of mine rescue service interventions and under precisely defined conditions, can replace the aforementioned backbone working insulated overpressure regenerative breathing apparatuses. Recently, mining rescue services in deep coal mines have been more and more often conducted under conditions of an irrespirable mine atmosphere containing high concentrations of carbon monoxide, but at the same time containing sufficient oxygen for the breathing physiology of mine rescuer (for example, interventions dealing with the disposal of machinery under conditions of occurrence of endogenous mining fire of coal). This fact, after a long time, has resumed again the discussion of miners' rescue experts about whether it would be possible to implement the use of breathing apparatuses filtrating carbon monoxide into practice by the Mining Rescue Services of the Czech Republic in order to ensure a sufficient level of safety for mining rescuers even in an unexpected and rapid decline of the oxygen amount in the mine air at the site of the mine rescue service. The benefit of the breathing apparatuses filtrating carbon monoxide is their significantly lower weight, long protection period and also significantly smaller dimensions and design variability of the device. The disadvantages are higher breathing resistances and a higher temperature of the air mass inhaled from the breathing apparatus filtrating carbon monoxide

Možnosti použití značkovacího plynu

The paper describes hexafluoride sulfur (6SF) as a chemical compound and its chemical attributes. It also describes in detail a way of using 6SF as a tracer gas for analyses of mining ventilation. 6SF was investigated by the Bureau of Mines in the USA together with other organic and inorganic compounds and radioactive substances. 6SF was found as a suitable tracer gas. The next chapter deals with the application of 6SF (in situ) at the Frenštát Mine.Tento článek ve stručnosti popisuje hexafluorid síry (6SF) jako chemickou sloučeninu a jeho chemické vlastnosti. Podrobněji je v tomto příspěvku popsán způsob využití 6SF jako značkovací plyn při analýzách důlního větrání. 6SF byl zkoumán Báňským úřadem v USA spolu s ostatními organickými i anorganickými sloučeninami a radioaktivními látkami. 6SF byl shledán vhodný jako značkovací plyn. Další kapitola pojednává o vlastním použití 6SF (in situ) na Dole Frenštát