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  • Author: Przemysław Bukowski x
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Comparison of Applications Supporting Selection and Design of Household Solar Collector Systems

Abstract

In order to support the designing process and selection of subassemblies of an installation, specialist application programs are created. Selected applications were compared in the paper through their use for designing hypothetical solar collector systems for a single family house with a varied number of household members. With the use of particular applications, calculations for the same input assumptions were made. Results obtained with the use of a traditional calculation method were a reference point. Applications were compared on account of the type and amount of input parameters which may be introduced, type and number of determined values and their value. Based on the obtained results usefulness and scope of use of an application were assessed.

Open access
Technical and Economic Analysis of Use of Post-Treatment Water as a Source of Heat for Heating Water in Breeding Tanks

Abstract

The paper presents a recommendation on how to use waste heat of post-treatment water in the balneological institute in Lądek Zdrój health resort. This heat may be used in stenothermal fish big scale breeding. The presented innovative solution of a technological breeding line of African sharptooth catfish (Clarias gariepinus) has not been carried out in practice yet and except for ecological values, it may soon bring real profits. The presented calculations show that the analysed technology may bring a real return of the incurred investment expenditures after approx. 6.5 years from the moment the production was launched. The calculated internal return rate is 14.25% and considerably exceeds the border rate (4%). As it was shown, there is an additional possibility of improvement of this profitability through the use of funding as a part of the Operational Programme Fisheries and Sea 2014-2020. Then, at the funding of investment in the amount of 50% of qualified costs IRR will increase to 25.03%. The period of capital return will decrease to approximately 3.5 years.

Open access
The Impact of Infrasounds Generated by Wind Power Stations on a Human Being

Abstract

In some opinion-forming environments the problem of noise emitted by wind power stations is very controversial. It is even suggested that they negatively affect the quality and length of human life. Based on the review of domestic and foreign publications an analysis of the impact of the low-frequency noise on a human being was carried out. Wind power stations operating in groups (farms) constituted the source of noise. It was proved that the level of acoustic pressure with G weighting does not exceed the value of 85 dB. The value of the admissible burdensome noise (102 dB) was exceeded in the bus cabins which were driving with the speed exceeding 30 km·h−1. The opinion of the Ministry of Health confirms the findings. It proves that the present knowledge does not allow a clear indication of the relation between the wind farms and their negative impact on the human health.

Open access
Modeling and Analysis of Ground Settlement Between a Flyover and Reinforced Soil Embankment

Abstract

Development of the transport infrastructure in Poland has contributed to the implementation of various technologies of construction of bridges and their components. Use of reinforced soil for construction of embankments, retaining structures (RSS walls) and abutments is one of the solutions which has been frequently used for the past twenty years. Shortly after its development, the technology proposed by Henri Vidal in 1966 also gained appreciation in Poland [4]. Reinforced soil bridge abutments started to be widely used in Poland at the turn of the 20th century. The bridge facilities at the junction of Trasa Siekierkowska route and Wał Miedzeszyński Street in Warsaw, which were built in the years 2000÷2002, are an example of structures from that period. The authors of this paper have been particularly interested in the outermost supports of the reinforced concrete flyovers which were constructed in the form of intermediate reinforced soil abutments. Offsets – the vertical displacements, in the range of 15÷25mm, emerging between the level of the road surface and the steel elements of the expansion joints which separate the flyover’s structure from the embankment – were observed in 2015, in the course of regular inspections. While accounting for the observations which have been made, the surveying measurements and the ground investigation, the paper diagnoses and describes the mechanism which led to the emergence of the offsets. Potential patterns of the occurrence of additional settlements, as the reason for emergence of the offsets, were identified and analyzed. The settlement of the outermost support (abutment), as a result of increase of relative density of alluvial sands due to the dynamic interaction of the roadways of Wał Miedzeszyński Street, was analyzed. Analytical and numeric approaches were used in the course of analysis while relying on PLAXIS and MIDAS software.

Open access