Ensuring access to a stable supply of a number of raw materials has become a serious challenge for domestic and regional economies with limited production, the EU economy alike. Reliable and unconstrained access to certain raw materials is an ever more serious concern. In order to tackle this challenge, the European Commission has established a list of Critical Raw Materials (CRMs) for the EU, which is regularly reviewed and updated. In its Communication COM(217) 490 final of September 13, 2017, the European Commission presented an updated list of 27 critical raw materials for the EU as a result of a third assessment based on a refined methodology developed by the Commission. Economic Importance (EI) and Supply Risk (SR) have remained the two main parameters to determine the criticality of a given raw material. The list of critical raw materials for the EU includes raw materials that reach or exceed the thresholds for both parameters set by the European Commission. The only exception is coking coal (included in the list of critical raw materials for the first time in 2014) which, although not reaching the economic importance threshold, has been conditionally kept on the 2017 list for the sake of caution. Should it not fully meet this criterion, it will be withdrawn from the list during the next assessment.
The article discusses the most important changes to the methodology used in the third review and their impacts on the coking coal criticality assessment. It presents the geographical structure of coking coal global production and consumption as well as the degree to which the EU is reliant on coking coal imports. Raw materials, even if not classified as critical raw materials, are essential for the European economy as they are at the beginning of manufacturing value chains. Their availability may change rapidly due to developments in trade flows or trade policy, which reveals the general need for the diversification of supply.
The aim of the present study was to explore the role of temporal intelligence in English as a Foreign Language (EFL) learners’ self-regulation and self-efficacy. To this end, a general temporal intelligence (GTI-S) scale was designed based on the subconstructs of time in the literature. The scale, along with the learning self-regulation questionnaire (SRQ-L) and the English self-efficacy scale was administered to 520 EFL learners. To validate the GTI-S, confirmatory factor analysis (CFA) was run. The results of Pearson product-moment correlations demonstrated significantly positive relationships between temporal intelligence and controlled self-regulation, automatic self-regulation and self-efficacy (p<.05). Moreover, the findings of multiple regressions revealed that Linearity of Time, Economicity of Time, and Multitasking are the most important subconstructs of time with relation to these variables.
The article presents selected issues from the Polish Energy Policy draft until 2040. From many issues, the authors chose the ones they considered the most revolutionary. Firstly, the National Power System should be restructured to meet the challenges of a changing environment, be adapted to the growing demand for electricity, and at the same time have the least impact on the natural environment. These goals can be achieved through reforms to reduce the importance of coal in the energy mix and the development of renewable energy sources, especially offshore wind energy. The next tasks are the development of electromobility, enabling the reduction of pollution caused by transport, and, in the longer term, after 2030, the development of nuclear energy in place of the withdrawn coal power.
The possibility of the application of nontraditional method of greenhouse gas utilization by the injection of CO2 (sequestration) into porous geological deposits, treated as unconventional gas collectors, requires the fulfillment of basic criteria such as the impact on the environment and long term storage. The important issue is the physical behavior of the deposit during the porous structure saturation phase by carbon dioxide. What should be mentioned first and foremost is: the availability of CO2 transport along the porous structure and adsorption capacity. The work presents the results of water vapor sorption on coal samples from selected Hard Coal Mines of a differentiated carbon content. The received results were presented in the form of sorption and desorption isotherms performed in a temperature of 303 K. It was additionally described with a BET adsorption isotherm. Based on sorption data, a specific surface area was calculated, in accordance with BET theory. The amount of the adsorbed water vapor molecules for the analyzed coal samples was dependent on the degree of metamorphism. The obtained isotherms can be described as type II according to the BET classification. Volumetric type apparatus -adsorption- microburette liquid was used for the sorption experiments. Water vapor sorption in relation to coals allows for the quantitative determination of primary adsorption centers as a measure of adsorbed molecule interconnections with the adsorbent surface. Based on the BET adsorption equation, out of water vapor isotherms, the amount of adsorption active centers, which potentially may take part in CO2 adsorption in coal seams during injection of this gas, was determined. The sorption capacity of coals is determined by the degree of metamorphism, which also has very large impact on the sorption capacity of the deposit.
The authors studied the fracture mechanical properties under half-symmetric loading in this paper. The stress distribution around the crack tip and the stress intensity factor of three kinds of notched specimens under half symmetric loading were compared. The maximum tensile stress σmax of double notch specimens was much greater than that of single notch specimens and the maximum shear stress τmax was almost equal, which means that the single notch specimens were more prone to Mode II fractures. The intensity factors KII of central notch specimens were very small compared with other specimens and they induced Mode I fractures. For both double notch and single notch specimens, KII was kept at a constant level and did not change with the change of a/h, and KII was much larger than KI. KII has the potential to reach its fracture toughness KIIC before KI and Mode II fractures occurred. Rock-like materials were introduced to produce single notch specimens. Test results show that the crack had been initiated at the crack tip and propagated along the original notch face, and a Mode II fracture occurred. There was no relationship between the peak load and the original notch length. The average value of KIIC was about 0.602 MPa×m1/2, and KIIC was about 3.8 times KIC. The half symmetric loading test of single notch specimens was one of the most effective methods to obtain a true Mode II fracture and determine Mode fracture toughness.