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Abstract

Niniejsza publikacja przedstawia metodykę DEA jako narzędzie do oceny efektywności technologii energetycznych. W pierwszej części pracy ukazano podstawowe narzędzia wykorzystywane do oceny portfela projektów inwestycyjnych w przemyśle energetycznym. W dalszej części scharakteryzowano metody Data Envelopment Analysis (DEA), czyli nieparametryczne procedury ustalania efektywności technologicznej badanych obiektów pod względem analizowanych czynników. W części praktycznej – wykorzystując analizę DEA – dokonano przykładowej oceny efektywności trzynastu technologii energetycznych, w tym technologii nadkrytycznego spalania węgla, zgazowania węgla połączonego z turbiną gazową oraz samodzielnego układu turbiny gazowej. Do analizy wykorzystano model nadefektywności nieradialnej z uwzględnieniem podziału na nakłady decyzyjne, niedecyzyjne oraz produkty pożądane i niepożądane. Dodatkowo przeprowadzona została analiza wyników dla przykładowej technologii. Zostały wytłumaczone możliwe sposoby interpretacji wyników końcowych z punktu widzenia obiektów efektywnych, jak i nieefektywnych. W tym drugim przypadku przedstawiono także kalkulację rozwiązania wzorcowego dla danej instalacji wraz z wnioskami co do skali działalności.
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Abstract

The subject of the paper is the analysis of factors determining the value of multi-entity organizations in the energy sector and their ranking according to the degree of impact on this value. For this purpose, statistical methods were used, which are best suited to determine the order of diagnostic features according to a specific criterion. The survey covered companies from the Polish energy sector, while the process itself is based on aggregated data, which represents the financial data of capital groups currently operating in the Polish energy sector. The first part of the article presents a short description of the Polish energy sector, paying particular attention to the organizational structure of the sector, i.e. companies operating on the domestic energy market. The nature of a multi-entity enterprise as a typical economic unit in the sector is described. The second part of the article describes the assumptions of multidimensional comparative analysis (MCA) as a tool for comparing multifunctional units. The MCA makes it possible to find the most important parameters or indicators having the greatest impact on the value of a multi-entity organization, i.e. a capital group. The survey covered four companies from the Polish energy sector: TAURON Polska Energia SA, ENEA SA, ENERGA SA and PGE Polska Grupa Energetyczna SA. The study with the use of MCA was conducted in three stages: - in the first stage, on the basis of information contained in the financial statements, a matrix of diagnostic features was created, describing the financial condition of the examined entity, - in the second stage, the values of diagnostic variables were normalized/unified; two methods of normalization were applied: the method of standardization and zero unitization, - in the third stage, the diagnostic variables were grouped using two methods: the model measure of Hellwig’s development and the non-standard measure of development. The results of the analysis are illustrated by tables and figures.
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Abstract

The study presents the results of theoretical investigations into lateral torsional buckling (LTB) of bi-symmetric I-beams, elastically restrained against warping at supports. Beam loading schemes commonly used in practice are taken into account. The whole range of stiffness of the support joints, from free warping to warping fully restrained, is considered. To determine the critical moment, the energy method is used. The function of the beam twist angle is described with power polynomials that have simple physical interpretation. Computer programs written in symbolic language for numerical analysis are developed. General approximation formulas are devised. Detailed calculations are performed for beams with end-plate joints. Critical moments determined with programs and approximation formulas are compared with the results obtained by other researchers and with those produced by FEM. Very good accuracy of results is obtained.
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