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Number of results: 6
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Abstract

The article focuses on two aspects of the end of the First World War. Recalled is the interpretation of the WW1 as a ‘seminal catastrophe’ of the twentieth century. This opinion does not apply, however, to the countries of East Central Europe that regained independence in the year 1918. Taking Poland as an example, we can point to three levels of internal discussions which took place after 1918. First, a debate evolved around the nation-building process and whether the nation which regained independence should be regarded as a purely ethnically-based or political community. The political breakthrough moreover triggered debates concerning the state-building process through an attempt at creating structures of a strong, modern state; lastly, discussed were attempts to find a place for a reborn Poland on the international scene.
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Abstract

Poland is now faced with the task of developing a long-term energy policy for decades to come, a strategy capable of reconciling the security of power supplies as well as effective economic processes, ensuring adequate standards of environmental protection. The process in which fossil fuels are converted into energy carriers of choice is accompanied by the emission of various gas substances which escape into the environment. Later on, those substances accumulate in the atmosphere as greenhouse gases affecting the Earth’s radiation balance – the greenhouse effect. Upsetting the balance between emission levels of those gases and the capacity to convert them in the atmosphere is the reason for climate changes. Sustainable development indices constitute a monitoring tool which makes it possible to create a statistical image of a country from the perspective of a new development paradigm. The most important feature of this index is the capability of comparing values, enabling to determine the position of a given object with reference to other objects. The article analyses 8 indexes of sustainable development in terms of using biomass for power generation purposes. The analysis was performed to include three social order indices, two economic indices and one environmental order index. It was concluded that the use of biomass in power generation can reduce the emission of greenhouse gasses significantly at several stages: the emission can be eliminated from the biological process of biomass conversion, storage and it can also be reduced during transportation.
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Abstract

The iron ore mine owned by the state concern of Luossavaara – Kiirunavaara AB-LKAB state concern has several mining skip shaft hoists for drawing iron ore. Despite using modern systems to secure the travel of these hoists in line with the Swedish regulations, units intended for the emergency breaking of vessels must be used in the so-called free travel paths in the tower and in the shaft sump. The paper discusses the main requirements that, in accordance with the Swedish regulations as regards the operational use of mining shaft hoists, must be met by devices of this type and a solution was proposed for a structure design of the braking unit for the mining shaft hoist installed in the B-1 shaft in the Kiruna mine. The frictional braking system in the form of moving bumping beams was decided to be used in the said hoist, developed in the Cable Transport Department in the University of Science and Technology in Krakow. The action of moving bumping beams consists in these beams, placed at the beginning of free travel paths, not only braking the rushing hoist vessels but also (with the integrated units for vessel capture) performing the function of grips. They secure the vessels against falling down into the shaft after the finished braking process. The advantage of such a solution is that the structural elements: the guiding shank of the tower, the head of the vessel and the bumping beams, transfer many times lower values of dynamic forces at the time of the strike of the vessel against the moving bumping beams when compared with dynamic forces arising at the time of the hit of the vessel against the fixed bumping beams. In the process of designing moving bumping beams, braking simulation is an important stage conducted with a computer program developed in KTL AGH. This program enables the modelling of load-bearing and balance ropes as flexible elements with elastic and suppressing properties. The results of these simulations, especially in the scope of the achieved braking deceleration of the vessels, the values of braking distances and forces in the load-bearing ropes are crucial in confirming the correctness of the assumed concept of the emergency braking system. The braking units in the form of moving bumping beams have been executed by the Polish company Coal-Bud Sp. z o.o. and are now being integrated in the tower and in the shaft sump of the B-1 shaft of the Kiruna mine in Sweden.
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Abstract

Hard bitumens are used in the construction industry primarily in it’s unmodified form, for instance for the production of the so-called traditional roofing felt. Due to the low price of these types of membranes, the use of a popular but expensive modifying agent, SBS copolymer, is not justified economically. Research carried out by the authors has shown that chemical organic compounds belonging to a group of imidazolines may potentially be used as much cheaper bitumen modifier. It was demonstrated that a new type of modifier based on oleic imidazoline, developed by the authors, has a significant impact on improving the physical properties of bitumen. The use of this modifier results in a significant increase in the bitumen plasticity range, both before and after laboratory ageing .In addition, there was a considerable increase of bitumen’s resistance to aging. Its use can help improve the quality and durability of popular waterproofing products manufactured with the use of hard bitumen.
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Abstract

In this study, emulsified kerosene was investigated to improve the flotation performance of ultrafine coal. For this purpose, NP-10 surfactant was used to form the emulsified kerosene. Results showed that the emulsified kerosene increased the recovery of ultrafine coal compared to kerosene. This study also revealed the effect of independent variables (emulsified collector dosage (ECD), frother dosage (FD) and impeller speed (IS)) on the responses (concentrate yield (γC %), concentrate ash content ( %) and combustible matter recovery (ε %)) based on Random Forest (RF) model and Genetic Algorithm (GA). The proposed models for γC %, % and ε% showed satisfactory results with R2. The optimal values of three test variables were computed as ECD = 330.39 g/t, FD = 75.50 g/t and IS = 1644 rpm by using GA. Responses at these experimental optimal conditions were γC % = 58.51%,  % = 21.7% and ε % = 82.83%. The results indicated that GA was a beneficial method to obtain the best values of the operating parameters. According to results obtained from optimal flotation conditions, kerosene consumption was reduced at the rate of about 20% with using the emulsified kerosene.
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Abstract

Oxidative stress (OxS) has been implicated in the pathogenesis of Crohn’s disease (CD). The aim of this study was to examine whether nonenzymatic antioxidants are associated with active CD, by using the FRAP and GSH assay in plasma. Additionally, we measured bilirubin and albumin levels as two individual components of the plasma antioxidant system. A total of 55 patients with established CD, 30 with active CD and 25 with inactive disease, and 25 healthy individuals were prospectively enrolled in this study. We evaluated CD activity index, BMI and blood morphology, platelet count, serum CRP level, and bochemical parameters of OxS: ferric reducing ability of plasma (FRAP), reduced glutathione (GSH) in plasma and bilirubin and albumin levels in serum. Plasma FRAP and GSH concentrations were decreased in both CD groups compared to controls and negatively correlated with CDAI values (FRAP: r = –0.572, p = 0.003; GSH: r = –0.761, p = 0.001), CRP and platelet count. Bilirubin and albumin levels were lower in the serum of active CD patients than inactive CD patients and controls and negatively correlated with the CD activity index (r = –0328, p = 0.036, r = –0.518, p = 0.002) and CRP (r = –0.433, p = 0.002). The decreased FRAP and GSH levels in plasma and bilirubin and albumin levels in serum of patients with active CD compared to inactive CD and controls underlines the importance of OxS in the pathophysiology and activity of CD.
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