Global brown coal resources are estimated to be extracted at around 512 million Mg. They are found in over a dozen countries, including primarily: Australia, China, the Czech Republic, Greece, Germany, Poland, Russia, the United States and Turkey. More than 80% of total brown coal production in the EU takes place in: Germany, Poland, Greece and the Czech Republic. This means that the majority of production still uses conventional fuels, including both hard coal and brown coal. Given the current energy needs in the context of brown coal reserves depletion and the impacts of the current climate and energy policies of the EU, it is very important that all new investments in mining and energy complexes based on brown coal resources must be prepared carefully to ensure high production efficiency and minimize negative environmental impacts. This article attempts to solve a problem involving the choice of the location of the opening cut to expose brown coal deposits. Due to the stratified nature of brown coal deposits and the associated open-cast mining technology used in a continuous mining system with bucket wheel excavators, belt conveyor systems and spreaders, the location of the opening cut is not completely random and the number of potential solutions is finite. The multifaceted technical, organizational, economic, social and environmental problems require a holistic approach to this research problem. Such an approach should take the different, often opposing, perspectives of the many stakeholders into account. These issues can be solved using mathematical tools designed for multiple-criteria decision support. With the proposed method, a ranking of alternatives can be created, depending on the predefined location of the opening cut.

The image analysis consists in extracting from the information which is available to the observer of the part that is important from the perspective of the investigated process. This process usually accompanies a considerable reduction in the amount of information from the image. In the field of two-phase flows, computer image analysis can be used to determine flow and geometric parameters of flow patterns. This article presents the possibilities of using this method to determine the void fraction, vapor quality, bubble velocity and the geometric dimensions of flow patterns. The use of computer image analysis methods is illustrated by the example of HFE 7100 refrigerant methoxynonafluorobutane condensation in a glass tubular minichannel. The high speed video camera was used for the study, and the films and individual frames received during the study were analyzed.

In the over 150 years of hydrocarbon history, the year 2017 will be one of the many similar. However, it will be a breakthrough year for liquefied natural gas. In Asia, China grew to become the leader of import growth, becoming the second world importer, overtaking even South Korea and chasing Japan. The Panama Canal for LNG trade and the “Northern Passage” was opened, so that Russian LNG supplies appeared in Europe. The year 2017 was marked by a dramatic shortening of the length of long-term concluded contracts, their shorter tenure and reduction of volumes – that is, it was another period of market commoditization of this energy resource. The article describes the current state of LNG production and trade till 2018. It focuses on natural gas production in the United States, Qatar, Australia, Russia as countries that can produce and supply LNG to the European Union. The issue of prices and the contracts terms in 2017 was analyzed in detail. The authors stress that the market is currently characterized by an oversupply and will last at least until mid–2020. Novatek, Total – Yamal-LNG project leaders have put the condensing facility at 5.5 million tons into operation. The Christophe de Margerie oil tanker was the first commercial unit to cross the route to Norway and then further to the UK without icebreakers and set a new record on the North Sea Road. In 2017, the Russian company increased its share in the European gas market from 33.1 to 34.7%. In 2017, Russia and Norway exported record volumes of „tubular” – classic natural gas to Europe (and Turkey), 194 and 122 billion m3 respectively, which is 15 and 9 billion m3 more natural gas than in 2016. The thesis was put forward that Russia would not easily give up its sphere of influence and would do everything and use various mechanisms, not only on the market, that it would simply be more expensive and economically unprofitable than natural gas. It was also emphasized that the pressure of the technically possible and economically viable redirection to European terminals of methane carriers landed in the American LNG, results in Gazprom not having a choice but to adjust its prices. The Americans, but also any other supplier (Australia?) can simply do the same and this awareness alone is enough for Russian gas to be present in Europe at a good price.

The paper presents a numerical model of the novel design of the axial magnetic bearing with six cylindrical poles. The motivation behind this idea was to eliminate vibrations in rotating machinery due to the axial load. Common conception of such a bearing provides a single component of the electromagnetic force, which is not enough to reduce transverse and lateral vibrations of the armature. The proposed design allows for avoiding wobbling of the disc with the use of a few axial force components that are able to actively compensate the axial load and stabilise the disc in a balanced position. Before a real device is manufactured, a virtual prototype should be prepared. The accurate numerical model will provide essential knowledge about the performance of the axial magnetic bearing.

Housing resources as an element of material infrastructure determine socio-economic development on a local, regional and national scale. Their economic and physical accessibility affects the development of human, social and relational capital, determines the competitiveness of the territory and can be seen as a generator of income both in the individual sense and in relation to the whole society. The article has a theoretical character and its aim is to identify the relationship between satisfying the housing needs of local communities and the development of territorial capital. The article also analyzes factors that allow the qualification of housing resources as a strategic resource for the development of a territory.

Investigations of refrigerant condensation in pipe minichannels are very challenging and complicated issue. Due to the multitude of influences very important is mathematical and computer modeling. Its allows for performing calculations for many different refrigerants under different flow conditions. A large number of experimental results published in the literature allows for experimental verification of correctness of the models. In this work is presented a mathematical model for calculation of flow resistance during condensation of refrigerants in the pipe minichannel. The model was developed in environment based on conservation equations. The results of calculations were verified by authors own experimental investigations results.

This paper presents a study of the effect of the modification and cooling rate on the grain count α(Al) in the Al-5Cu alloy. Research was

performed on castings with walls thickness between 3 mm and 25 mm. Cooling curves were recorded to determine the cooling rate and the

degree of undercooling at the beginning of solidification. It has been shown that cooling rate increases exponentially as the wall thickness

of casting decreases. Moreover it has been demonstrated that the cooling rate of castings changes within a wide range (21ºC/s - 1ºC/s)

when the wall thickness changes from 3 up to 25 mm. Metallographic examinations revealed primary grains (primary α(Al) grains). The

paper show that the relationship between the grain count and the degree of undercooling (for non-modified and modified alloys) can be

represented by the equation N = Nv = np·exp(-b/ΔTα), based on the Weibull's distribution of the size of nucleation sites.