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Abstract

It is commonly known that the cause of serious accidents in underground coal mining is methane. Thus, computational fluid dynamics (CFD) becomes a useful tool to simulate methane dispersion and to evaluate the performance of the ventilation system in order to prevent mine accidents related to methane. In this study, numerical and experimental studies of the methane concentration and air velocity behaviour were carried out. The experiment was conducted in an auxiliary ventilated coal heading in Turkish Hard Coal Enterprises (TTK), which is the most predominant coal producer in Turkey. The simulations were modeled using Fluent-Ansys v.12. Significant correlations were found when experimental values and modeling results were compared with statistical analysis. The CFD modeling of the methane and air velocity in the headings especially uses in auxiliary ventilation systems of places where it is hard to measure or when the measurements made are inadequate.
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Bibliography

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Authors and Affiliations

Gülnaz Daloğlu
1
Mustafa Önder
1
Teresa Parra
2

  1. Eskişehir Osmangazi Üniversitesi Müh. Mim. Fak. Maden Mühendi sliği Bölümü, 26480 Eskişehir, Turkey
  2. University of Valladolid, Department of Energy and Fluid Mechanics, Valladolid, Spain
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Abstract

Among the elements that compose steel slags and blast furnace slags, metallic precipitates occur alongside the dominant glass and crystalline phases. Their main component is metallic iron, the content of which varies from about 90% to 99% in steel slags, while in blast furnace slags the presence of precipitates was identified with the proportion of metallic iron amounting to 100%. During observations using scanning electron microscopy and X-ray spectral microanalysis it has been found that the form of occurrence of metallic precipitates is varied. There were fine drops of metal among them, surrounded by glass, larger, single precipitates in a regular, spherical shape, and metallic aggregates filling the open spaces between the crystalline phases. Tests carried out for: slags resulting from the open-hearth process, slags that are a by-product of smelting in electric arc furnaces, blast furnace slags and waste resulting from the production of ductile cast iron showed that depending on the type of slag, the proportion and form of metallic precipitates is variable and the amount of Fe in the precipitates is also varied. Research shows that in terms of quality, steel and blast furnace slag can be a potential source of iron recovery. However, further quantitative analyses are required regarding the percentage of precipitates in the composition of slags in order to determine the viability of iron recovery. This paper is the first part of a series of publications aimed at understanding the functional properties of steel and blast furnace slags in the aspect of their destructive impact on the components of devices involved in the process of their processing, which is a significant operational problem.

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Authors and Affiliations

Andrzej Norbert Wieczorek
Iwona Jonczy
ORCID: ORCID
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Abstract

Studies were carried out in the summer seasons of l 995-1999 (from June to September) on the quantitative and qualitative composition of Enterobacteriaceae bacteria (including Escherichia coli and Salmonella sp.), and potentially pathogenic bacteria Aeromonas hydrophila, Pseudomonas aeruginosa and Staphylococcus sp. in the water of 8 bathing sites of the Lake Wigry. Aeromonas hydrophila occurred in the all samples of studied water and was the most numerous in water sampled from sites of increased trophic levels. Irrespective of the site and time of sampling Pseudomonas aeruginosa was rarely isolated. In the total of 160 samples of water analysed Salmonella sp.. Escherichia coli and Staphyloccocus aureus were determined in 32 (22.6%), 68 (42.4%) and 90 (55%) samples, respectively. Pathogenic bacteria of the genus Salmonella sp. and potentially pathogenic Staphylococcus aureus and Aeromonas hydrophila identified in the analysed offshore waters (also when Escherichia coli were absent) suggest that the use of the Lake Wigry waters for swimming, falling into account faecal bacterial counts, may not be sufficient to fully reflect safety conditions for bathers. The results of the research suggest that the evaluation of the Lake Wigry surface waters for recreational use should include the frequency of the occurrence of Salmonella sp., Staphylococcus aureus, Aeromonas hydrophila and Pseudomonas aeruginosa. These three species, which arc not directly linked to faecal contamination, can cause various diseases of the skin, nasal and oral cavities, eyes, internal car and other problems in people swimming in contaminated water.
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Authors and Affiliations

Ewa Korzeniewska
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Abstract

Electric cars (SE) are currently considered to be one of the best ways to reduce CO2 and other air emissions in the transport sector as well as noise in cities. They can reduce the dependency of road transport on imported oil in a visible way. Nevertheless, the demand for electricity for a large amount of SE in road transport is not insignificant and has an impact on the power system. The article analyzes the potential impact of SE on the demand, supply, structure and costs of electricity generation as well as emissions as a result of introducing 1 million SEs by 2025 on Polish roads, and tripling this number by 2035. The competitive electricity market model ORCED was used for the calculations. The results of the analysis indicate that regardless of the charging strategy, the demand for SEs causes a slight increase in the overall electricity demand in Poland and consequently also a slight increase in power generating costs. Even a large increase in SEs in road transport will result in a rather moderate demand for additional generation capacity, assuming that power companies will have some control over the mode of charging cars. The introduction of SEs will not reduce CO2 emissions compared to conventional cars in 2025, on the contrary will increase them regardless of the loading strategy. In 2035 however, the result depends on the charging scenario and both the increase or decrease of emissions is possible. Electric vehicles will increase SO2 net emissions, but they will contribute to a decrease in the net emissions of particulates and NOx.

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Authors and Affiliations

Uroš Radović
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Abstract

This article surveys the relations between the Polish Radio and the German Broadcasting Corporation (Reichs-Rundfunk-Gesellschaft) in the interwar period. In its early phase the relationship was overshadowed by disputes over programmes on Upper Silesia and the takeover by a German company of the radio station in the Free City of Gdańsk (Danzig). After Hitler became chancellor in 1933 there was a marked improve- ment in relations: the two parties even made an agreement to relay each other's programmes. However, in September 1939 the German radio network (RRG) actively aided the German army in its invasion of Poland.

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Authors and Affiliations

Sebastian Fikus

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