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Abstract

In the Fore-Sudetic Monocline area, gas deposits occur in carbonate rocks of cyclothems PZ1 (Zechstein limestone Ca1) and PZ2 (main dolomite Ca2). The location of deposits is closely connected with zones of carbonate sedimentation. Generally, gas deposits occur within barrier zones and at the foot of carbonate platforms. The outburst of rock fragments into the heading of the KGHM Rudna mine in 2009 was evidence that gas could also appear in the basin zone Ca1 of the copper deposit. 2D and 3D surface seismic surveys comprise the basic method which is applied to hydrocarbon prospecting. The main advantage of this method is the fact that P-wave velocity and bulk density decrease as a result of gas saturation of the pore spaces. As a result, one can observe anomalous seismic [records(activity?)] which can be connected with gas deposits, and reservoir interpretation of seismic data is based on Direct Hydrocarbon Indicators analysis (DHI). This paper presents and compares seismic images of gas saturation [in traps(trapped?)] in a typical carbonate barrier (Kościan gas field in Ca1) at the foot of a carbonate platform (Lubiatów gas field in Ca2), and in a porous/fractured zone in Ca1 dolomite where there was a gas outburst in the Rudna mine. Based on available well logging data and 1D seismic modeling (synthetic seismograms) this study developed criteria for identification of gas-saturated zones for each case. The results of the study provide the following basic criteria for gas saturation: (1) phase change at Ca1 bottom from negative at the basin zone to positive at the barrier zone - for the Kościan barrier Ca1; (2) the bright spot at the top of the saturated zone - for the Lubiatów deposit at the foot of the carbonate platform; (3) reflections with close to zero amplitude at the bottom of Ca1 dolomites - for the porous and fractured deep-water zone of the Rudna mine.

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Authors and Affiliations

Jerzy Dec
Kaja Pietsch
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Abstract

The article discusses the evolution of Marian Smoluchowski’s reasoning in his research on causality and understanding the essence of chance. Initially, Smoluchowski focused on the epistemic study of causality, looking for evidence supporting the kinetic-molecular theory. In proving the causes of Brownian motion, he used the concepts of physical causality. The fundamental change in Polish physicist's perception of causality was the understanding of the position of chance on the cause-effect line. Introducing mathematical relations into his considerations, he analyzed the aspect of the occurrence of the effect. The chance suitable for calculating probability was distinguished from the chance in a broader sense by the essential regularity of the frequent recurrence of the phenomenon, regardless of the knowledge of the cause. Smoluchowski's merit was the distinction between the philosophical and physical understanding of causality, chance and probability theory. Shifting the considerations on the nature of chance to the ontological plane moved the study of chance into the area of science, thus leading to the practical application of probability theory in physics.
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Authors and Affiliations

Jan Grzanka
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Abstract

This paper compares selected optimization-based methods for the analysis of multibody systems with redundant constraints. The following numerical schemes are examined: direct integration method, Udwadia-Kalaba formulation, two types of least-squares block solution method and Udwadia-Phohomsiri formulation. In order to compare efficiency of the algorithms, a series of simulations is performed on two exemplary McPherson struts. In the first variant, the mechanism has no redundant constraints whereas the other is overconstrained. Three constraint stabilization schemes are also compared in terms of integration errors.

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Authors and Affiliations

Marcin Pękal
Janusz Frączek

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