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Abstract

The reflection coefficient of the open end belongs among the essential parameters in the physical description of a flue organ pipe. It leads directly to practical topics such as the pipe scaling. In this article, sound propagation is investigated inside an organ pipe with the most intense mean flow that is achievable under musically relevant conditions. A theoretical model is tested against the experimental data to obtain a suitable formula for the reflection coefficient when a non-negligible flow through the open end is considered. The velocity profile is examined by means of particle image velocimetry. A fully developed turbulent profile is found and interactions of the acoustic boundary layer with the turbulent internal flow are discussed. A higher value of the end correction than expected from the classical result of Levine and Schwinger is found, but this feature shall be associated with the pipe wall thickness rather than the mean flow effects.
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Bibliography

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Authors and Affiliations

Viktor Hruška
1
Pavel Dlask
1

  1. Academy of Performing Arts in Prague, Musical Acoustics Research Centre, Prague, Czech Republic
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Abstract

The paper presents the concept of a fully planar treeshaped antenna with quasi-fractal geometry. The shape of the proposed radiator is based on a multi-resonant structure. Developed planar tree has symmetrical branches with different length and is fed by a coplanar waveguide (CPW) with modified edge of the ground plane. The antenna of size 29 mm x25 mm has been designed on Taconic - RF-35 substrate (r = 3.5, tg= 0.0018, h = 0.762 mm). The paper shows simulated and measured characteristics of return loss, as well as measured radiation patterns. The proposed antenna could be a good candidate for broadband applications (for instance: wideband imaging for medical application and weather monitoring radars in satellite communication etc.)

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Authors and Affiliations

Małgorzata Malinowska
Marek Kitliński
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Abstract

The aim of this study was to identify thoroughly the geological structure of the Choszczno Anticline for potential CO2 storage. The paper presents the interpretation of seismic materials for a selected seismic profile reprocessed into a section of reflection coefficients characterized by increased recording resolution as compared to the wave image. Particular attention was paid to the geological complexes associated with the Jurassic reservoir formations suitable for carbon dioxide storage within the anticline. The correlation of the identified layers reflects the lithology and structure of the rock series. It allows determination of the thicknesses of the series and changes within them, and enables linking the individual layers with the lithologic units, based on geological data. The study refers to the whole Zechstein-Mesozoic succession of the Choszczno Anticline, with special emphasis on these series, in which there are potential reservoir formations for CO2 storage. The interpretation has significantly expanded the amount of data provided in standard seismic documentations. While assessing the suitability of the formations for CO2 storage, special attention should be paid to the tectonic disturbances within the Komorowo Formation, especially in the top part of the Choszczno structure. The Reed Sandstone bed is more continuous in this respect. The obtained results seem to suggest wider application of reprocessing of seismic materials into effective reflection coefficients to study the geological structure, also for other structures.

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Authors and Affiliations

Lidia Dziewińska
Radosław Tarkowski
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Abstract

This paper presents the results of an analysis of selected seismic profiles (reflection and refraction data) from the Radom-Lublin area aimed at obtaining a better understanding of geological structure and the identification of hydrocarbon deposits. To accurately reproduce the seismic reflection covering the sub-Permian formations, seismic cross sections were interpreted based on effective reflection coefficients (ERC). In interpreting the results, reference was made to the results of studies of the area using other geophysical methods.
The results of these studies made it possible to obtain new information on the geology and structure of the Paleozoic complex of the Radom-Lublin area and its relationships with the basement tectonics. The structural arrangement of Carboniferous and Devonian formations as well as older Silurian, Ordovician, and Cambrian series were recognized. Selected significant tectonic and lithological discontinuities and the nature and directions of their course were characterized. Special attention was given to regional tectonic zones: the Skrzynno Fault, the Ursynów-Kazimierz fault zone and the Kock zone. The use of ERC methodology made it possible to define the boundaries of lithostratigraphic units in Carboniferous, Devonian, and older formations. The obtained results can be used to assess hydrocarbon accumulation in the area under consideration.
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Authors and Affiliations

Lidia Dziewińska
1
ORCID: ORCID
Radosław Tarkowski
1
ORCID: ORCID

  1. Mineral and Energy Economy Research Institute, Polish Academy of Sciences, Kraków, Poland

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