Search Results

1 - 5 of 5 items

  • Author: Małgorzata Ulewicz x
Clear All Modify Search

Abstract

This article constitutes an analysis of the influence of public financial support on the process of replacement of the asbestos-cement sheets used as a roof covering for materials safe for the environment. Commonly used asbestos-cement sheets, known under the commercial name of „Eternit”, should be removed of civil structures by 2032 following a program established by the Polish state. However, the carried-out analysis indicates that until present times the products containing asbestos have been properly identified in all municipalities across Poland, and also the amount of financial support that a property owner may obtain for removal of products containing asbestos is relatively low comparing to the costs of the roofing replacement. The cost of roof covering replacement falls within the range. 18.417 – 41.232 PLN/m2, so for the roof area of 100 m2 and considering the simplest roof structure (gable roof) the cost would total between 18.417 and 41.232 PLN. Therefore the existing system of public financial support providing funds for asbestos removal only will not affect the investor’s decision regarding replacement of roof covering and increase of civil structures safety. The replacement process of dangerous Eternit roof covering is slow and most probably the established programmed will not be completed on time.

Abstract

In this study, palladium-modified nickel foam substrate was applied to examine ethanol oxidation reaction (EOR) in 0.1 The transport of cobalt(II), nickel(II), copper(II), and zinc(II) ions from chloride solutions across polymer inclusion membranes (PIMs), which 1-heptylimidazole (1̲) or 1-heptyl-2-methylimidazole (2̲) or 1-heptyl-4-methylimidazole (3̲) as the ion carrier was reported. The steric effect for carriers 2̲and 3̲decreases the transport of all ions except Cu(II). The initial fl uxes of metal ions transport across PIMs with the 1̲- 2̲decrease in the sequence: Cu(II) > Zn(II) > Co(II) > Ni(II), whereas for 3 they were Cu(II) > Zn(II) > Ni(II) > Co(II). The highest recovery values were obtained for Cu(II), this being 99 and 85% for carrier 1̲and 2̲, respectively. In both membranes the degree of deposition of the Zn(II) ions was comparable. Zn(II), Co(II) and Cd(II) ions, which form complexes with coordination numbers 4 and 6, are more easily recovered with the use of carriers 2̲and 3̲. Ni(II) ions, which form complexes with coordination number 6 only, practically remain in the feeding phase. PIMs with alkylimidazoles were characterized by non-contact atomic force microscopy.

Abstract

This paper presents the analysis of existing forms of heat absorbing surfaces of air solar collectors, which gained the greatest popularity in the world. The obtained data allowed to conclude that there is a need for the development of solar collectors with air as a coolant with an improved form of heat absorber, which will reduce the operational and capital costs of solar systems and allow the efficient use of such structures in a moderate climate without additional mechanisms for the transfer of coolant. The use of computer simulation helped to compare the thermal characteristics of air-borne solar collectors of a different design. The substantiation of the expediency of installing as a heat absorber of flow turbulators in the form of a screw has been fulfilled, as well as the height of the air channel of the solar collector has been determined, in which the maximum heating of the transfer medium is observed. In addition, the loss of pressure in the air channel of the solar collector with flow turbulators was determined and the comparison of the obtained data with the values of pressure losses in the air collector of the matrix type and the air collector with V-shaped ribs was made.

Abstract

This article presents guidelines developed by the Research Institute of Roads and Bridges for estimating the loss of the load capacity and determining the time between failures of steel road bridges resulting from corrosion. Mathematical relationships which enable the determination of load capacity and durability of bridge structures were discussed. Reduction coefficients required to calculate the percentage decrease of the load bearing capacity of the corroded structure and reduction coefficients that are significant in determining the degree to which lifespan of the structure is shortened were defined. Mathematical algorithms of presented method made it possible to obtain information, that are necessary for further maintenance and possible modernization of the bridge in Wisla.

Abstract

The following article discusses the problem of durability of girders made of structural steel S355 affected by corrosion. It presents the Polish procedure for calculating the time between failures of steel elements of bridge and durability factors necessary to estimate the impact of corrosion on the durability of steel road bridges. According to the presented procedure, two real bridges of steel structure were analysed. The bridges selected for analysis are located in extremely different corrosive environments in Poland. This bridges were built in different areas of the country which are characterized by different (mountain, urban) aggressiveness of the environment. The objects of the analysis differ in terms of corrosion type occurring on the bearing system. Their age is also different which has a significant impact on their safety.The results obtained allowed to determine the time when, with the existing corrosion damage, failures may occur.