This January was the time to summary results of cytotoxicity experiments. Thus multilayer polyelectrolyte films consist of chitosan/chondroitin sulfate polymers exhibit a fast biodegradability in the environment of human tissues. Lifetime extension of this material type could be implemented by its structure stabilization through the introduction of nanoparticles. Transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) methods were used to determine the microstructure and localization of the silicon carbide nanoparticles introduced to the extracellular like structure of the polymer coatings. Modified coatings biocompatibility was analyzed in cytotoxicity assay and microscopic observations of endothelial cells growth on the material surface.

Last month I submitted an abstract entitled
"Toward effective analysis of large grain boundary data sets"
for the ICOTOM conference. I did some work
concerning comparison of experimentally obtained
grain boundary distributions with
grain boundary energy models and atomistic simulation data available in literature.

In january heating stage have been installed, and series of experiments have been performed, among them in-situ recrystallization of KoBo deformed titanium. Temperatures of heating experiment have been chosen basing on previously performed DSC analysis of KoBo deformed titanium. This analysis yielded two distinct peaks corresponding to exothermic phenomena related to recrystallization process. EBSD map have been collected from sample at room temperature, and then temperature have been increased to beginning of first peak. This was accompanied by sudden drop of diffraction pattern quality. Even though time was given for system to stabilize after temperature increase, pattern quality was low quality until the temperature was increased to temperatures over second crystallization peak from DSC analysis. Since limited time was available experiment could not be repeated. In future experiments either longer time for system stabilization should be allowed, or much smaller heating speed should be chosen.
Microstructure obtained after last temperature increase was completely recrystallized with coarse equiaxed grains, however texture have not evolved during this heating experiment.

This month I sent two applications for Conferences:
1) 17-th International Conference on Textures of Materials (24-29.08.2014 Dresen, Germany);
2) XV International Conference on Electron Microscopy (15-18.09.2014 Cracow, Poland).

I prepared abstracts for these conferences:
1) „Microstructure and texture changes during annealing of particle containing AA3004 aluminum alloy deformed by ECAP”
authors: J.Poplewska, H.Paul, A.Tarasek
2) “Effect of second phase particles on microstructure changes during annealing of Al-alloys pre-deformed by ECAP”
authors: J.Poplewska, H.Paul, K.Berent

Worked to improve the orientation and disorientation calculator. While in the case of parameterization Rodriguez Vector representation does not cause many problems , apart from the need to become familiar with the shape of the primary zones for orientation and disorientation , the Euler parameterization of a challenge. The first observation is that the data supplied from the TSL program in the form of a matrix orientation expressed as Euler angles ( φ1 , Φ , φ2 ) are not brought to the area of ​​basic orientation . Perhaps it can be set in the program, but due to the difficult access to equipment and generalization of the calculation in the calculator and so it is impossible to avoid these transformations . The fact that the orientations are not reduced to the primary area can be seen at the level of individual grains which have a consistent orientation of the domain . Such grains can not be described on average one three numbers ( φ1 , Φ , φ2 ), but his relationship orientation has n equivalence classes (n depend on the symmetry of the crystallites ) , due to the lack of conversion to one particular area of ​​the primary .
The next problem was how to draw Euler angles of the rotation matrix . Angles drawn in accordance with the formula φ1 = ArcTan [- g [ [ 3, 2 ]] g [ [ 3, 1 ]]] , Φ = ArcCos [g [ [ 3, 3 ]]] , φ2 = ArcTan [g [ [ 2, 3 ] ] , g [ [ 1, 3 ]]] , where the function ArcTan meant extensive arkus tangent , taking into account the sign of expressions. Then had properly wrap Euler angles , as these drawn from the matrix of rotation could be negative. The first step was to add or subtract one period 2π , that is modulo 2π to perform an operation on each of the angles. Then , if the angle Φ exceeded π , to be added to φ1 and φ2 value of π , and for the new Φ recognize the value of 2π - Φ . Then again , of course, had to bring the angles φ1 and φ2 to φ1 numbers mod ( 2π ) and φ2 mod ( 2π ) .