Kraków, Poland
Kraków, Poland

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Knych T.,Akademia Gomiczo Hutnicza | Smyrak B.,Akademia Gomiczo Hutnicza | Walkowicz M.,Akademia Gomiczo Hutnicza
Przeglad Elektrotechniczny | Year: 2011

During wiring system design used in public utility facility there is necessary to pay particular attention to the conservation of cables in high temperature. At the moment when the fire appeared the important is to reduce, in high step, the possibility of flames spreading and simultaneously avert danger of toxic smoke formation. Above requirements fulfill so-called fireproof and self-extinguishing cables, which insulating coat is made of slow-burning and halogen-free materials. In such way of construction, as a conductor material is Cu-ETP copper mainly used. However, in view of susceptibility of Cu-ETP copper to so-called hydrogen embrittlement in high temperatures, in those place is mostly used oxygen free copper. Lack of oxygen in copper removes danger of hydrogen disease, thereby, gives warranty the longest works of systems of the cables in fire conditions. In work there were made tests which main aim was resistance's estimation on hydrogen disease of copper conductors of Cu-ETP and Cu-OFE class, both with halogen-free isolation and without. Essential source of information estimating conservation of cables under high temperature were description of their properties resistance and structure observation after the process of annealing in different temperatures.

A characteristic of the Nordberg HP700 cone crusher, which is applied for production of fine dolomite aggregates, was presented in the article. The device work assessment in pilot plant scale, for changeable feed particle size distribution and capacity, was made. The improper work conditions in relationship to the excessive feed content of fine grains and their influence on device's capacity were presented, and the right characteristics of parameters determining the proper operation of the cone granulator was also determined.

Experiments were performed to investigate the hard coal behaviour while accumulating mine gases and the changes in its external dimensions that accompany this process. Sorption of mine gases brings about an increase of external dimensions of coal, and their desorption is accompanied by coal contraction. The results show that coal expansion is more pronounced in the direction perpendicular (ε ⊥) to the bedding than parallel to it (ε //). The equilibrium condition both in sorption and expansion processes can be reached more quickly in the coal-CO 2 than for coal-CO 4 systems. In spite of the fact that coals tend to sorb CO 2 much more effectively than CH 4, their deformation ability due to sorption is three times greater during sorption of carbon dioxide than for methane. The tests reveal that injection of carbon dioxide to the coalbed containing methane may lead to increased stresses in the rock strata as the coal will not be able to expand any further and this will cause changes of the seam permeability.

The paper summarizes the results of experimental testing of carbon dioxide sorption on three coal samples. For each sample, sorption tests were done at three temperatures, in the pressure range 0-3 MPa. The values of the isosteric heat of sorption and the work of expansion and desorption were derived for the investigated sorption systems. Test data reveal that the isosteric heat for hard coals is inversely proportional to the "reserve" of volumetric work - a major parameter triggering the sudden release of gas from the coalbed, thus enabling us to assess the potential risk involved in rapid unsealing of the coalbed.

Stryszewski M.,Akademia Gomiczo Hutnicza | Lochanska D.,Akademia Gomiczo Hutnicza
Prace Naukowe Instytutu Gornictwa Politechniki Wroclawskiej | Year: 2012

Rock materials play the crucial role in the economy of any country, in the building industry, communication, chemical and metallurgical industries, and many others. Rock materials are exploited in a continuous way in subsequent years and the amount of output depends on temporary demand. Rock materials exploiting sites tend to be located in extensive areas and therefore there is always freedom of locating a new production site as well as further development of the existing one. The role and function of a rock materials region depends mainly on the size of raw materials base and its quality, but also on mutual distribution of regions in relation to one another, their recipients and the existing spatial infrastructure of the region, its natural, cultural, and educational values. All the above factors influence the role and function of raw materials regions as the result of numerous consistent or exclusive reasons. The analysis was prepared on the example of southern regions of Poland.

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