Multilayer films containing α- and β-casein and polypeptides, poly-L-lysine (PLL), and poly-L-arginine (PLArg) were formed by the layer-by-layer technique and Fourier Transform InfraRed spectroscopy with Attenuated Total Reflection (FTIR-ATR) and FTIR/Grazing Angle analyzed their infrared spectra. We investigated the changes of conformations of casein and polypeptides in the complexes formed during the build-up of the films. To elucidate the differences in the mechanism of complex formation leading to various growths of (PLL/casein)n and (PLArg/casein)n films, we performed the molecular dynamics simulations of the systems consisting of short PLL and PLArg chains and the representative peptide chains—casein fragments, which consists of several aminoacid sequences. The results of the simulation indicated the preferential formation of hydrogen bonds of poly-L-arginine with phosphoserine and glutamic acid residues of caseins. FTIR spectra confirmed those, which revealed greater conformational changes during the formation of casein complex with poly-L-arginine than with poly-L-lysine resulting from stronger interactions, which was also reflected in the bigger growth of (PLArg/casein)n films with the number of deposited layers.

The effect of forward and reverse torsion on flow behavior and microstructure evolution, particularly dynamic and static spheroidization, on Ti-6Al-4V with an alpha lamella colony microstructure was studied. Testing was undertaken sub beta transus [1088 K (815°C)] at strain rates of either 0.05 or 0.5 s À1 . Quantitative metallography and electron back scatter diffraction has identified that a critical monotonic strain (e c ) in the range of 0.3 to 0.6 is required to initiate rapid dynamic spheroidization of the alpha lamella. For material deformed to strains below e c and then reversed to a zero net strain the orientation relationships between alpha colonies are close to ideal Burgers, enabling prior beta grains to be fully reconstructed. Material deformed to strains greater than e c and reversed lose Burgers and no beta reconstruction is possible, suggesting e c is the strain required to generate break-up of lamella. Static spheroidization is, however, sensitive to strain path around e c . Annealing at 1088 K (815°C) for 4 hours for material subjected to 0.25 forward + 0.25 forward strain produces 48 pct spheroidized grains while material with 0.25 forward + 0.25 reverse strain has 10 pct spheroidization. This is believed to be a direct consequence of different levels of the stored energy between these two strain paths.

The notion of fractals and the possibility of exploiting them in surface engineering are discussed. The fractal dimension problem is addressed and basic information relating to brushing and roughness parameters is provided. The results of tests on specimens in the form of structural steel (S275J0) plates subjected to brushing are presented. The machining was conducted using an FWD 32J milling machine with a GE 950 G PLUS straight grinder together with an A11-CB15M brush mounted on it. On the basis of the test results an analysis of selected roughness parameters, with the focus on the different degrees of correlation between the particular indicators and the fractal dimension, was carried out.