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Abstract

This article presents the results of research on the importance of access to critical raw materials for the development of wind energy in Poland. The authors have built a set of factors that can potentially influence this development. Twenty-four explanatory variables were taken into account, which were assigned to five categories. The amount of demand for mineral resources related to the development of wind technology was determined using a computer programwritten by the authors. The importance of individual factors was verified using the ARMAX model. As a result of this, it was possible to identify the explanatory variables that significantly affect the volume of wind energy production in Poland. The group of mineral resources includes critical metals that are necessary for the production of wind turbines. These are rare earth elements, copper, nickel, boron and manganese. The ARMAX model enables the examination of the relationship between the explained variable and the explanatory variables. Optimization of the model parameters was performed by limiting the mean square error. During the validation of the model, the VIF (variance inflation factor), Dickey-Fuller and Doornik-Hansen tests were used. The ARMAX validation also consisted of selecting the model characterized by the lowest value of information criteria and determining ex post errors, including the mean absolute percentage error (MAPE). In addition, the nature of individual independent variables was determined, i.e. whether they were stimulants, nominants, or destimulants. The forecast made it possible to verify the possibility of meeting the assumptions of the Polish Energy Policy until 2040. It showed that if the development trends of the factors that affect wind energy do not change, it would be possible to meet the assumptions of PEP2040 regarding the dynamic development of wind farms in Poland and double the generation capacity by 2030. Analysis using the ARMAX model showed that access to raw materials such as REE, Cu, Ni, Br and Mn would have a very significant impact on the development of wind energy in Poland. Each factor of the raw material category that was introduced into the model was considered statistically significant at the significance level of α = 0.01, i.e. at the lowest acceptable risk of error. Therefore, the raw material base would be of key importance to ensure access to wind energy at the level adopted in PEP2040.
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Authors and Affiliations

Aurelia Rybak
1
ORCID: ORCID
Aleksandra Rybak
1
ORCID: ORCID

  1. Silesian University of Technology, Gliwice, Poland
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Abstract

This paper discusses changes in the microstructure and abrasive wear resistance of G17CrMo5-5 cast steel modified with rare earth metals

(REM). The changes were assessed using scanning microscopy. The wear response was determined in the Miller test to ASTM G75.

Abrasion tests were supplemented with the surface profile measurements of non-modified and modified cast steel using a Talysurf CCI

optical profilometer. It was demonstrated that the modification substantially affected the microstructure of the alloy, leading to grain size

reduction and changed morphology of non-metallic inclusions. The observed changes in the microstructure resulted in a three times higher

impact strength (from 33 to 99 kJ/cm2

) and more than two times higher resistance to cracking (from 116 to 250 MPa). The following

surface parameters were computed: Sa: Arithmetic mean deviation of the surface, Sq: Root-mean-square deviation of the surface, Sp:

Maximum height of the peak

Sv: Maximum depth of the valley, Sz: Ten Point Average, Ssk: Asymmetry of the surface, Sku: Kurtosis of the surface. The findings also

indicated that the addition of rare earth metals had a positive effect on the abrasion behaviour of G17CrMo5-5 cast steel.

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Authors and Affiliations

B. Kalandyk
J. Kasińska
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Abstract

The paper describes influence of rare earth metals (REMs) on G20Mn5 cast steel microstructure and mechanical properties. The cerium mixture of the following composition was used to modify cast steel: 49.8% Ce, 21.8% La, 17.1% Nd, 5,5% Pr and 5.35% of REMs. Cast steel was melted in industrial conditions. Two melts of non-modified and modified cast steel were made. Test ingots were subject to heat treatment by hardening (920°C/water) and tempering (720°C/air). Heat treatment processes were also performed in industrial conditions. After cutting flashes off samples of cast steel were collected with purpose to analyze chemical composition, a tensile test and impact toughness tests were conducted and microstructure was subject to observations. Modification with use of mischmetal did not cause significant changes in cast steel tensile strength and yield strength, while higher values were detected for fractures in the Charpy impact test, as they were twice as high as values for the data included in the PN-EN 10213:2008 standard. Observations performed by means of light and scanning microscopy proved occurrence of significant differences in grain dimensions and morphology of non-metallic inclusions. Adding REMs resulted in grain fragmentation and transformed inclusion shapes to rounded ones. Chemical composition analyses indicated that round inclusions in modified cast steel were generally oxysulphides containing cerium and lanthanum. In the paper the author proved positive influence of modification on G20Mn5 cast steel mechanical properties.
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Authors and Affiliations

J. Kasińska
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Abstract

The effect of the complex ligature with nickel and REM (Ce, La) aluminides on the structure formation, the nature of the distribution of the elements, and the microhardness of the structural constituents of Al-5 wt.% Cu aluminum alloy were investigated. On the example of microalloying of the Al-5 wt.% Cu alloy with a master alloy containing Ni and REM (Ce, La) aluminides it was shown that a redistribution of Al and Cu occurs in α-solid solution and eutectic. This is reflected in the refinement of α-solid solution and eutectic at 0.15 wt.% of the master alloy addition and, accordingly, increases the microhardness of α-solid solution by 100 MPa and eutectic by 125 MPa.

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Authors and Affiliations

E. Ri
K. Ri
V. Deev
E. Prusov

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