Fabrication and microstructure of the AlSi11 matrix composite containing 10 % volume fraction of CrFe30C8 particles were presented in this paper. Composite suspension was manufactured by using mechanical stirring. During stirring process the temperature of liquid metal, time of mixing and rotational speed of mixer were fixed. After stirring process composite suspension was gravity cast into shell mould. The composites were cast, applying simultaneously an electromagnetic field. The aim of the present study was to determine the effect of changes in the frequency of the current power inductor on the morphology of the reinforcing phase in the aluminum matrix. The concept is based on the assumption that a chromium-iron matrix of CrFe30C8 particles dissolves and residual carbide phases will substantially strengthen the composite. The microstructure and interface structure of the AlSi11/CrFe30C8 composite has been studied by optical microscopy, scanning microscopy and X-ray diffraction.

Surface prospection at site 5 in Nieprowice, Pińczów county, Świętokrzyskie voivodship, revealed a quite large series of Roman coins (33 specimens), accompanied by numerous and differentiated artefacts of the Przeworsk culture. Many of the artefacts are metal decorations and elements of dress that usually provide precise dating of archaeological sites. Site 5 at Nieprowice was occupied by people of the Przeworsk culture beginning with phase A2 of the younger Pre-Roman Period to the beginning of the Migration Period. The coins are exceptionally abundant and they are more differentiated than it is usual in surface prospection on the sites of the Przeworsk culture settlements, hence this place could be a central settlement in the region.

In this paper three algorithms of motion planning for two-input, one-chained nonholonomic systems are presented. The classical Murray-Sastry algorithm is compared with two original algorithms aimed at optimizing energy of controls. Based on the generalized Campbell- Baker-Hausdorff-Dynkin formula applied to the systems, some observations are made concerning the optimal relationship between amplitudes and phases of harmonic controls. The observations help to optimize a selection of controls and to design new algorithms for planning a sub- optimal trajectory between given boundary configurations. It was also shown that for those particular systems the generalized C-B-H-D formula is valid not only locally (as in a typical case) but also globally. Simulations performed on the five-dimensional chain system facilitate distinguishing the proposed algorithms from the Murray-Sastry algorithm and to illustrate their features. Systems in a chained form are important from a practical point of view as they are canonical for a class of systems transformable into this form. The most prominent among them are mobile robots with or without trailers.

In this paper a small time local controllability, naturally defined in a configuration space, is transferred into a task-space. It was given its analytical characterization and practical implications. A special attention was put on singular configurations. Theoretical considerations were illustrated with two calculation examples. An extensive comparison of the proposed construction with the controllability defined in an endogenous configuration space approach was presented pointing out to their advantages and disadvantages.

Introduction: Graves’ Disease (GD) is an autoimmune hyperthyroidism occurring mostly in young women. The main pathogenic role of the disease is attributed to TSH receptor antibodies (TRAb), which stimulate the thyroid gland to increase production of the most active thyroid hormone- triiodothyronine (T3). High level of TRAb and a large goiter size are commonly known as poor prognostic factors for the disease and are used to predict relapse.

The aim: The purpose of our study was to check the correlation between fT3:fT4 ratio with TRAb concentration, total volume of thyroid and age of GD onset.

Materials and Methods: 114 patients with onset or relapse of GD were analyzed. Those after thyroidectomy or radioiodine therapy were not taken into analysis. The data was retrospectively retrieved from the hospital’s records consisting of patients’ sex, age, level of TRAb, fT3, fT4 and thyroid volume on ultrasonography. The association between fT3:fT4 and TRAb concentration, thyroid volume and age was evaluated using Pearson correlation coefficient.

Results: The group was predominated by women (19.3% men, 80.7% women). The average age was 47.0. The analysis revealed positive correlation between: 1) fT3:fT4 ratio and total volume of thyroid (correla-tion ratio: 0.37; p <0.05) 2) fT3:fT4 ratio and level of TRAb (correlation ratio: 0.26; p <0.05) 3) negative correlation between fT3:fT4 ratio and patient’s age (correlation ratio: –0.14; p = 0.144.

Conclusions: Positive correlations between fT3:fT4 ratio and TRAb level and total volume of thyroid (poor predictors of GD) may confirm that high level of fT3 can also be a prognostic factor for GD severity.