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Number of results: 9
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Abstract

Author explains a necessity of supply optimization to construction sites with small storage areas. This paper takes account of conditions existing in Poland. From among all factors discussed by the author, first of all, we should point at construction works on plots located in densely built-up areas, obtained by demolition of existing buildings, as well as a necessity of plots utilization after demolished buildings that technical conditions do not allow for further exploitation.
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Abstract

The text comprises the evaluation of relationship between the qualitative planning tools and the Irish housing policy in the pre-crisis period, during the crisis (2009-2013) and the recovery. The tools that affect housing are understood as spatial planning, including governmental regulations on densification of the development and the housing quality as well as the special tools such as the urban design. Those regulatory tools were deployed with aims to safeguard the sustainable and socially viable housing structures. The Irish case illustrates the considerable innovation in introducing new housing standards and challenges with their efficiency. This can be attributed to the lack of integration with other elements that shaped the market – financing and actions of the private market, low efficiency of planning or the lack of the scale effect for the model developments. Despite their drawbacks these tools are continuously being used, as their foundational principles are still valid.
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Abstract

The Stirling engine type alpha is composed of two cylinders (expansion space E and compression space C), regenerator that forms the space between the cylinders and the buffer space (under the pistons). Before the start-up and as a result of long-term operation, the average pressure in the working space (above the pistons) and in the buffer space is the same. However, in the initial phase of operation, the average pressure in the working space is different then the average pressure in the buffer space depending on the crankshaft starting position (starting angle). This, in turn, causes a large variation in the starting torque. An additional unfavorable factor caused by a large variation in the course of the indicated torque is the rotational speed variation and the formation of torsional vibrations in the drive system. After some time, depending on the quality of the engine piston sealing, the average pressure in the working and buffer space will equalize. The occurrence of the above-described phenomenon affects the selection of the starting electric motor, which can be significantly reduced, when the crankshaft starting position is optimized (the starting torque is several times greater than the average torque occurring in the generator operation mode). This paper presents the analysis of the impact of the crankshaft starting position on the course of the indicated torque and the resulting start-up energy. Starting the engine at an unfavorable position of the crankshaft may, in extreme cases, increase the starting torque even three times.
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Abstract

In view of the world’s recent changes in the mineral market, it is becoming increasingly important to ensure the sustainable and secure supply of raw materials, both within the European Union and in other high-developed countries. In response to this global challenge, as part of the European Commission’s Horizon 2020 Program for Research & Innovation, the 36-month INTRAW project was launched in February 2015 to foster international cooperation on raw materials. The EU-funded INTRAW project was set up to map and develop new cooperation opportunities related to raw materials between the EU and other technologically advanced countries, such as: Australia, Canada, Japan, South Africa and the United States. The first stage of the project was a review of conditions for the stable supply of raw materials from primary and secondary sources in selected countries: the United States, Canada, Australia, South Africa and Japan. The results of the work are two groups of comprehensive reports. The first of these is a broad contextual analysis of geological, environmental, political, technical -economic and social factors conducive to the effective management of mineral resources. The second group is operational reports, carried out in three thematic blocks: industry and trade, research and innovation, education. The analysis clearly shows that the basis for effective action in this area is a stable political, economic and institutional environment, which is friendly to mining and new entities wishing to invest in modern technologies, the exploration and exploitation of deposits. Investors are encouraged by tax regulations, sometimes also by direct government financial support and efficient licensing procedures. The well-defined protection of property rights, also for deposits is equally important. Selected aspects of a wide analysis of determinants of competitiveness for these countries were presented in the article below.
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Abstract

In order to improve the efficiency and ensure the security of power supply used in a mine, this paper mainly studies the quasi-resonant flyback secondary power supply and analyzes its operational principles based on the requirements of soft-switching technology. In accordance with the maximum energy of a short-circuit and the request of maximum output voltage ripple, this paper calculates the spectrum value of the output filter capacitor and provides its design and procedures to determine the parameters of the main circuit of power supply. The correctness and availability of this theory are eventually validated by experiments.
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Abstract

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.
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Abstract

The article concerns safety of power supply for the final consumers, especially its two comprising elements, which are generation adequacy and distribution system reliability. Generation adequacy has been defined with Loss of Load Probability (LOLP), Loss of Load Expectation (LOLE) and Energy Not Supplied (ENS) indices. Conclusions from generation adequacy forecast prepared by ENSTO-E for Poland compared with other European countries for the years 2020 and 2025 have been discussed along with the resulting threats. Interruptions in energy supply have been characterised by power discontinuity indicator SAIDI. Finally, a reliability and adequacy analysis have been performed for different scenarios of the Polish power system operation in order to assess possibilities of using distributed generation as a backup power source. Based on a simulation model created using the DIgSILENT Power Factory software, the reliability and adequacy calculations have been performed with the probabilistic non-sequential Monte Carlo method and they are followed by a discussion of the obtained results.
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