Extensions of C*-dynamical systems to systems with complete transfer operators

Starting from an arbitrary endomorphism $\alpha$ of a unital C*-algebra $A$ we construct a bigger C*-algebra $B$ and extend $\alpha$ onto $B$ in such a way that the extended endomorphism $\alpha$ has a unital kernel and a hereditary range, i.e. there exists a unique non-degenerate transfer operator for $(B,\alpha)$, called the complete transfer operator. The pair $(B,\alpha)$ is universal with respect to a suitable notion of a covariant representation and depends on a choice of an ideal in $A$. The construction enables a natural definition of the crossed product for arbitrary $\alpha$.Comment: Compressed and submitted version, 9 page

Postglacial expansion of the arctic keystone copepod calanus glacialis

Calanus glacialis, a major contributor to zooplankton biomass in the Arctic shelf seas, is a key link between primary production and higher trophic levels that may be sensitive to climate warming. The aim of this study was to explore genetic variation in contemporary populations of this species to infer possible changes during the Quaternary period, and to assess its population structure in both space and time. Calanus glacialis was sampled in the fjords of Spitsbergen (Hornsund and Kongsfjorden) in 2003, 2004, 2006, 2009 and 2012. The sequence of a mitochondrial marker, belonging to the ND5 gene, selected for the study was 1249 base pairs long and distinguished 75 unique haplotypes among 140 individuals that formed three main clades. There was no detectable pattern in the distribution of haplotypes by geographic distance or over time. Interestingly, a Bayesian skyline plot suggested that a 1000-fold increase in population size occurred approximately 10,000 years before present, suggesting a species expansion after the Last Glacial Maximum.GAME from the National Science Centre, the Polish Ministry of Science and Higher Education Iuventus Plus [IP2014 050573]; FCT-PT [CCMAR/Multi/04326/2013]; [2011/03/B/NZ8/02876

Application of grid convergence index in FE computation

This paper presents an application of the grid convergence index (GCI) concept based on the Richardson extrapolation to a selected simple problem of a cantilever beam loaded with vertical forces at the tip end. The GCI method, popular in computational fluid dynamics, has been recently recommended for finite element (FE) applications in solid and structural mechanics. Based on the results obtained usually for three meshes, the GCI method enables one to determine, in an objective manner, the order of convergence to estimate the asymptotic solution and the bounds for discretization error. The example shows that the characteristics of the convergence depend on the selection of the quantity of interest, which can be local or a global functional such as the deflection considered here. The results differ for different FE formulations, and the difference is bigger when the nonlinearities (e.g., due to plastic response) are taken into account

Application of grid convergence index in FE computation

This paper presents an application of the grid convergence index (GCI) concept based on the Richardson extrapolation to a selected simple problem of a cantilever beam loaded with vertical forces at the tip end. The GCI method, popular in computational fluid dynamics, has been recently recommended for finite element (FE) applications in solid and structural mechanics. Based on the results obtained usually for three meshes, the GCI method enables one to determine, in an objective manner, the order of convergence to estimate the asymptotic solution and the bounds for discretization error. The example shows that the characteristics of the convergence depend on the selection of the quantity of interest, which can be local or a global functional such as the deflection considered here. The results differ for different FE formulations, and the difference is bigger when the nonlinearities (e.g., due to plastic response) are taken into account

Diagnosti? methods in active insuring reliability systems of hydraulic machine drives

W artykule przedstawiono strukturę i metody zabezpieczenia niezawodności napędów hydraulicznych. Opisano również schemat sterowania procesami określającymi niezawodność układów hydraulicznych.The article introduced the structure and protection methods of hydraulic drives reliability. There were also described the hydraulic arrangements patern defining the reliability of processes

Numeryczne modelowanie zespolonych słupów stalowo-betonowych

This paper presents the numerical part of the research program on concrete-filled steel columns. Nonlinear, three dimensional FE analysis of axial compression, was conducted using the finite element program ABAQUS. The numerical results were validated through comparison with experimental data in terms of ultimate loading and deformation modes. Modeling related problems such as the definition of boundary conditions, imperfections, concrete-steel interaction, material representation and others are investigated using a comprehensive parametric study. The developed FE models will be used for an enhanced interpretation of experiments and for the predictive study of cases not included in the experimental testing.W artykule przedstawiono numeryczną część programu badań słupów stalowych wypełnionych betonem. Przeprowadzono nieliniową, trójwymiarową analizę FE ściskania osiowego, za pomocą programu ABAQUS. Numeryczne wyniki zostały zwalidowane przez porównanie z danymi doświadczalnymi w zakresie obciążenia granicznego i typu odkształcenia. Za pomocą kompleksowych studiów parametrycznych badano zagadnienia związane z modelowaniem takich parametrów jak określenie warunków brzegowych, imperfekcji, interakcji miedzy betonem a stalą, odwzorowaniem materiałów. Opracowane modele FE zostaną wykorzystane do udoskonalenia interpretacji eksperymentów i przewidywania wyników dla przypadków niebadanych doświadczalnie

Example of experimental validation and calibration of a finite element model of a heavy vehicle

An example of the experimental validation ofafinite element model of a selected heavy vehicle is presented in the paper. A truck tractor with a three axle single drop lowboy trailer and the total weight of 20 tons was selected as a representative for the tests. The major goal of the conducted studies was to develop a well validated the numerical model of a heavy vehicle applicable for computer simulation of dynamic interaction between a vehicle and a bridge or road structure. Therefore, only several components of the vehicle, affecting the vehicle-road interaction, like wheels and the suspension systems, were modelled in detail. The rest of components were simplified and considered as rigid bodies. The finite element model included fully pneumatic tires and the suspension system modelled with discrete massless springs and dampers. Numerical analyzes were performed using the LS-DYNA computer code. The validation and calibration procedure proposed in the current paper was carried out in two steps. In the first one, some parameters such as material densities, thickness of selected elements, were modified to achieve the correct mass distribution in the model based on the measured axle loads. In the next step the stiffness and damping parameters of the suspension system were evaluated based on the results of the experimental tests. The spring and damping coefflcients at all axles were adjusted until the performance of the FE model closely matched that of the actual vehicle

Dylematy inwestycyjne wdrażania technologii zgazowania w Polsce

Gasification technology is often seen as a synonym for the clean and efficient processing of solid fuels into combustible gas containing mainly carbon monoxide and hydrogen, the two basic components of synthesis gas. First and foremost, the facts that gas may be cleaned and that a mixture with any composition may be prepared in a relatively easy and inexpensive manner influence the possibility of using gas produced in the energy and chemical industries. In the energy industry, gas may be used directly to generate heat and electricity in the systems of a steam power plant or in combined cycle systems. It is also possible to effectively separate CO2 from the system. However, in chemistry, synthesis gas may be used to produce hydrogen, methanol, synthetic gasolines, and other chemical products. The raw material for gasification is full-quality pulverized coal, but a possibility of processing low-quality sludges, combustible fractions separated from municipal waste as well as industrial waste also exists. Despite such a wide application of technology and undoubted advantages thereof, making investment decisions is still subject to high uncertainty. The paper presents the main technological applications of gasification and analyzes the economic effectiveness thereof. In this context, significant challanges for the industrial implementation of this technology are discussed.Technologia zgazowania postrzegana jest często jako synonim czystego i efektywnego przetwórstwa paliw stałych do gazu palnego zawierającego głównie tlenek węgla i wodór – dwa podstawowe składniki gazu syntezowego. Możliwość stosunkowo łatwego i taniego oczyszczania gazu oraz komponowania jego składu pozwala na szerokie zastosowanie technologii w energetyce i przemyśle chemicznym. W energetyce gaz może być bezpośrednio użytkowany do wytwarzania ciepła i energii elektrycznej w układach siłowni parowej, względnie w układach gazowo-parowych. Dodatkową zaletą jest możliwość skutecznego i relatywnie taniego usuwania CO2 z układu. W chemii gaz syntezowy może służyć do wytwarzania wodoru, metanolu, benzyn syntetycznych i innych produktów chemicznych. Surowcem dla zgazowania może być zarówno miał węglowy, jak również paliwa niskojakościowe, w tym muły węglowe, palne frakcje wydzielane z odpadów komunalnych i odpadów przemysłowych. Mimo tak szerokich możliwości zastosowania technologii zgazowania oraz jej niewątpliwych zalet, podejmowanie decyzji inwestycyjnych obarczone jest ciągle dużą niepewnością. W artykule przedstawiono główne kierunki zastosowania technologii zgazowania i przeanalizowano ich efektywność ekonomiczną. W tym kontekście omówiono istotne uwarunkowania przemysłowego wdrożenia tej technologii