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Abstrakt

The paper presents the modeling of transmission of the ultrasonic plane wave through an uniform liquid layer. The considered sources of the ultrasonic wave were normal (straight) beam longitudinal wave probes and angle beam sheer waves probes commonly used in non-destructive testing. Coupling losses (CL) introduced by the presence of the coupling layer are discussed and determined applying the numerical procedure. The modeling applies to both monochromatic waves and short ultrasonic pulses with a specified frequency bandwidth. Model implementation and validation was performed using a specialized software. The predictions of the model were confirmed by coupling losses measurements for a normal beam longitudinal wave probe with a delay line made of polymethyl methacrylate (PMMA). The developed model can be useful in designing ultrasonic probes for high-speed rail track inspections, especially for establishing the optimal thickness of the water coupling layer and estimation of coupling losses, due to inevitable changes of the water gap during mobile rail inspection.
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Autorzy i Afiliacje

Sławomir Mackiewicz
1
Zbigniew Ranachowski
1
ORCID: ORCID
Tomasz Katz
1
Tomasz Debowski
1
Grzegorz Starzynski
1
Przemysław Ranachowski
1

  1. Institute Of Fundamental Technological Research Polish Academy Of Sciences Warsaw, Poland

Abstrakt

The aim of geological investigations the results of which are given in this paper was identify the presence of Carboniferous coal in the area south of Homsund (Figs. 1 and 2). The field investigations were carried out in the summer of 1979 within the scientific expedition organized by the Institute of Geophysics of the Polish Academy of Sciences (problem MR-II-16/B). The investigations covered the northwestern part of Sörkappland, south of Hornsund and west of the Wurmbrandegga and Wiederfjellet (Fig. 2).

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Autorzy i Afiliacje

Ireneusz Lipiarski
Stanisław Ćmiel

Abstrakt

The transformation of the former docks in Dublin was one of the major urban regeneration projects in Ireland, which was built during the recent economic boom. Since the start of the project in the nineties, more than six thousand apartments have been built in the area. The construction of the apartments allowed for the diversifi cation of the character of this district into a living quarter. Initially the Docklands were considered as an offi ce district that would serve the Ireland’s service-based economy. New projects also allowed for the development of housing in a close proximity to existing city centre, although it did not happen not without avoiding the gentrifi cation and social polarization of this area.

The key role in the process was played by the operator – the urban development agency (Dublin Docklands Development Authority). It acted both as a strategic landowner and the coordinator of the development. The agency was responsible for the delivery of the infrastructure and the sale of the land. The actions of the operator included setting up the of the housing standards, requirements for the development of the infrastructure, both social and technical and public transportation systems. In the hindsight, the agency was praised for the management of the development of such large site. On the other hand, the lack of procedural oversight and a few dubious fi nancial decisions, as well as the other eff ects of the neoliberal policies, such as gentrification, fi nally lower the assessment of DDDA efficiency in that matter.

The article summarizes the main aims and achievements of the DDDA’s development policy and its assessment from the long-term perspective of two decades of transformation. This includes the eff ects of the actions in the aftermath of the fi nancial crisis. Such perspective allows to highlight the various stages of the development of the agency and to examine the efficiency and efficacy of these actions.

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Autorzy i Afiliacje

Łukasz Pancewicz

Abstrakt

The paper describes the results of various actions and industrial tests conducted in order to decrease the content of unburned carbon in the fly ash of a circulating fluidised bed combustor (CFBC). Several attempts to improve the situation were made and the effects of several parameters on the unburned carbon content in the fly ash were investigated (e.g. bed temperature, cyclone separation efficiency, fuel particle size distribution, boiler hydrodynamics, grid design, and fuel data). Unfortunately, no satisfactory solution to these problems was found. Probably, apart from attrition and char fragmentation, additional factors also contributed to the formation of unburned carbon in the CFBC fly ash.

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Autorzy i Afiliacje

Rafał Kobyłecki

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