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Marta Skiba and Natalia Rzeszowska

Abstract

One of the five far-reaching goals of the European Union is climate change and sustainable energy use. The first step in the implementation of this task is to reduce energy demand in buildings to a minimum by 2021, and in the case of public buildings by 2019. This article analyses the possibility of improving energy efficiency in public buildings, the relationship between particular indicators of the demand for usable energy (UE), final energy (FE) and primary energy (PE) in buildings and the impact of these indicators on the assessment of energy efficiency in public buildings, based on 5 variants of extensive thermal renovation of a school building. The analysis of the abovementioned variants confirms that the thermal renovation of merely the outer envelope of the building is insufficient and requires the use of additional energy sources, for example RES. Moreover, each indicator of energy demand in the building plays a key role in assessing the energy efficiency of the building. For this reason it is important to analyze each of them individually, as well as the dependencies between them.

Open access

Mariusz Młynarczuk, Marta Skiba, Libor Sitek, Petr Hlaváček and Alena Kožušníková

Abstract

In recent years, water jet cutting technology has been being used more and more often, in various domains of human activity. Its numerous applications include cutting different materials - among them, rock materials. The present paper discusses the results of the research that aimed at determining - in a quantitative manner - the way in which the water jet cutting parameters (such as the traverse speed of the head, and the distance between the high-pressure inlet of the water jet and the cut material) influence the quality of the processed surface. Additionally, the impact of these parameters on the surface of various materials was investigated. The materials used were three granites differing with respect to the size of grains. In the course of the research, the standard parameters defined by the ISO norms were analyzed. It was also proposed that variograms be used to analyze the quality of the cut surface.

Open access

Marta Skiba, Agnieszka Pedrycz and Beata Cichacz

Abstract

Oxidative stress occurring in cells is a consequence of an excessive activity of reactive oxygen forms, resulting from an imbalance between the release of free oxygen radicals and their removal from the cell by antioxidant systems. 90% of reactive oxygen radicals emerge in mitochondrial respiratory chain during an incomplete four-electron oxygen reduction. The remaining 10% originate from different reactions occurring in the cell. The established compounds are characterised by a short half-life and are highly reactive. Sparse quantities of free oxygen radicals have a positive effect on cell functions. Oxidative stress leads to damage in cellular membranes, enzymatic and non-enzymatic proteins, as well as DNA. Therapy with antioxidants as exogenous dietary supplements aims at preventing or reducing the risk of development of diseases involving the presence of the oxygen radicals. Whether the antioxidant therapy will bring positive or negative effects depends on numerous factors that need to be considered before their inclusion in the applied treatment.

Open access

Andrzej Łączak, Anna Bazan-Krzywoszańska, Maria Mrówczyńska and Marta Skiba

Abstract

The article presents the present situation in terms of energy production from renewable energy sources and perspectives for development, based on research on the existing resources and possibilities of using them. The Lubusz Voivodship is not an important energy producer in Poland. In terms of the amount of energy produced it comes twelfth out of sixteen voivodships. The annual energy production from renewable energy sources is 290,9 GWh, which is 11.6% of the total energy produced. At the end of 2014 there were 73 licensed installations producing electrical energy from renewable energy sources in the Lubusz Voivodship with a total capacity of 189 MW. The largest amount of energy is produced by a pumped storage power plant (91,3 MW). The total capacity of the licensed installations using RES in the Lubusz Voivodship rose from 103 MW in 2007 to about 189 MW in 2014. Research on the existing resources indicates that it is possible to develop RES. Preparations are under way to build 66 new wind farms with a total capacity of 1834 MW [35], 89 photovoltaic power plants with a total capacity of 468 MW, 21 water power plants with a total capacity of about 60 MW, 54 biogas power plants with a total expected capacity of about 67 MW. The total capacity of the RES installations that are planned to be built by 2023 will be 2469 MW. Therefore, in the coming years the installed capacity of RES installations will increase 13 times in the Lubusz Voivodship. There are still no plans to use the energy of deep geothermal waters due to low profitability.