We investigated sediments of three Sphagnum peatland-lake ecosystems located in Tuchola forest, both in moraine (Małe Leniwe near Rekowo) and outwash plain (Dury and Rybie Oko) landscape. Geological cross-sections were studied for each basin. Characteristic feature of these ecosystems is the presence of floating mats encroaching the lakes and deposition of highly hydrated sediments below the floating mat. Principal conditions favouring the development of peatland-lake ecosystems are (1) location of the lake in a sandy, non-calcareous catchment overgrown by coniferous forest, (2) steep ness of the lake basin, what prevents emerged macrophytes succession and (3) the depth of the basin significantly exceeding 10 m to avoid complete in filling of the lake basin. The developmental pathway in the Dury I basin indicates a shift in lake environment from neutral to acid one. After initial development of Charophytes, Potamogeton and Najas expanded, which later on, were succeeded by Sphagnum due to acidification of the lake water. Initial stages of the development of the lakes were determined mainly by allogenic factors, whereas in later stages autogenic factors (development of floating mat and peat acidifying the lake water) played fundamental role.
The list of 29 gastropod species and 33 species of bivalves occurring in Hornsund Fiord as well as their zoogeographic status are presented. The occurrence and role of Mollusca in particular parts of the fiord are discussed.
In the second part of the article, the history of standardization programmes concerning the names of physiographic objects is discussed. The basis of the standardization programme currently followed by the Commission on Names of Localities and Physiographic Objects is described. The paper also presents the criteria of linguistic correctness adopted by the previous standardization commissions as well as by the present one. Issues of linguistic correctness of geographical names with dialectal properties and of names borrowed from minority languages are discussed. Attention is paid to some structural discrepancies in the approaches to the issue of correctness taken by the Commission on Names of Localities and Physiographic Objects and by local authorities.
In recent years, the outsourcing of a variety of different activities has been more commonly observed in the coal mining industry. This is connected with employing workers by external companies. These practices are not necessarily perceived as good ones by mines’ employees because they may influence their remuneration directly or indirectly. Firstly, as external employees treat work in mining company as a source of a quick income. Therefore, external companies often calculate their employees compensation not based on working time (i.e. hours) but on the basis of a specific, accomplished task. Such employment is called piecework, whereas the workers employed in this kind of system are called output workers/piece workers. Therefore, to receive higher wages in these companies, employees carry out their tasks faster and more efficiently. This, in turn, can affect the standards of workers employed by the mining company. In addition, outsourced workers are often retired miners, so the costs incurred by employers are significantly lower. In addition, in order to not to lose the retirement benefit, they work for a much lower rate. On the other hand, outsourced work can be done in a hurry (on a piece rate), which is not conducive to compliance with safety regulations, therefore mine employees may feel unsafe. This article aims to present how mine employees assess outsourcing underground works. In order to achieve this aim, a survey was carried out among employees of one of the coal mine companies in Silesia. Participants of the survey were randomly chosen among underground miners employed at one mine company. The survey was anonymous which obviously might have influenced respondents’ honesty in answering. The survey was carried out in several mines of the chosen company. In some of them the survey was carried out online and in the remaining ones it was filled out on paper. Analyzing the survey results allowed for a better understanding of the reasons of the disapproval of outsourcing underground works. This, in turn, may be used for better human resources management including, in particular, planning an incentive based pay system.
The paper presents selected issues related to the development of international coal markets. World consumption of coal dropped for the second year in a row in 2016, primarily due to the lower demand from China and the US. The share of coal in global primary energy consumption decreased to 28%. World coal production accounted to 3.66 billion toe and it was lower by 6.2% when compared to the previous year. More than 60% of this decline took place in China. The decline in global production was more than four times higher than the decrease in consumption. The sufficiency of the world resources of coal are estimated at 153 years – that is three times more than the sufficiency of oil and gas resources. After several years of decline, coal prices increased by 77% in 2016. The current spot prices are at the level of $80/ton and are close to the 2014 prices. In the European market, after the first half of the year, coal prices reached the level of around 66% higher than in the same period of the last year. The average price in the first half amounted to PLN 12.6/GJ, which is close to the 2012 prices. The share of spot trade in the total purchase amount accounted to approx. 20%. Prices in futures contracts can be estimated on the basis of the Japan-Australia contracts prices and prices in supplies to power plants located in Germany. On average, the prices in supplies to these power plants were higher by approximately 9% in the years 2010 – 2016 and prices in Australia – Japan contracts were 12% higher than CIF ARA prices in 2017. Global energy coal trade reached about 1.012 billion tons in 2016. A decline by 4.8% is expected in 2019 primarily due to the expected reduction in demand in major importing countries in Asia.
Compact radiators with circular polarization are important components of modern mobile communication systems. Their design is a challenging process which requires maintaining simultaneous control over several performance figures but also the structure size. In this work, a novel design framework for multi-stage constrained miniaturization of antennas with circular polarization is presented. The method involves se- quential optimization of the radiator in respect of selected performance figures and, eventually, the size. Optimizations are performed with iteratively increased number of design constraints. Numerical efficiency of the method is ensured using a fast local-search algorithm embedded in a trust-region framework. The proposed design framework is demonstrated using a compact planar radiator with circular polarization. The optimized antenna is characterized by a small size of 271 mm2 with 37% and 47% bandwidths in respect of 10 dB return loss and 3 dB axial ratio, respectively. The structure is benchmarked against the state-of-the-art circular polarization antennas. Numerical results are confirmed by measurements of the fabricated antenna prototype.
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