Design of polymer membrane morphology with prescribed structure and diffusion properties

We study the possibility of using numerical modelling in the process of design a membrane of prescribed morphology and transport properties. We started from a real example of the cross-section of alginate membrane cross-linked by glutaraldehyde containing 25 wt% magnetite particles and searched for a numerical model that will resemble its morphological properties like amount of polymer matrix, sizes of polymer matrix domains, fractal dimension and others. Two different methods of generating models of such were proposed. After choosing the best models based on its morphological similarities to the real membrane, we study their transport properties in terms of Brownian diffusion. We showed that there is a good agreement of diffusion type and diffusion constant between the models and the real membrane

Numerical study of drift influence on diffusion transport through the hybrid membrane

Sodium alginate membranes filled with iron oxide nanoparticles consist of a mixture of organic and inorganic phases. This design offers the possibility to combine the polymer’s easy processability and superior separation performance. For a better understanding of the mechanisms of mixture separation, we analyze the diffusion motion of a particle in the hybrid membrane environment. We model structures of two-dimensional heterogenic membranes, which resemble real membrane structures, and then we simulate a random walk on them. We investigate how the additional action of drift changes the motion properties of the diffusing particles through the polymeric membrane filled with inorganic powder. We test the effect of two parameters: the distribution of obstacles (filling) in the membrane and the value of drift on the nature of diffusion. It appears that the synergy between drift, the diffusion, and the membrane structure affect the occurrence of the superdiffusive and subdiffusive character of particle motion as measured by the time-averaged mean square displacement. An important point is the observation that the strong drift supports subdiffusive motion as it increases the chances of particle trapping. Moreover, there exists the optimal value of drift, for which the transport through a membrane speeds up and does not cause trapping

Interfacial tension at the interface of a system of molten oxide and molten steel

This paper is focused on a study of the interfacial tension between selected oxide and metal phases. The experimental research on the interfacial tension was performed in a horizontal resistive graphite Tamman furnace using an original method of measuring. This method consists of fixing both liquid phases in a horizontal position using a mandrel made of tungsten wire in a corundum cover. In this work the influence of the carbon content in the steel on the interfacial tension was studied. For this purpose a steel with 0.411 % of mass fraction of carbon and a steel with 2.64 % of carbon were used. Because of the wide variety of oxide systems used in industry, a characteristic system of casting powder was chosen for this study. This system contains dominant components, i.e., SiO2, CaO, Al2O3 and MgO, as well as a range of attendant mixtures, e.g., Fe2O3, TiO2 and Na2O. Simultaneously, the influence of SiO2 on the temperature dependence of the interfacial tension was observed. For this reason a concentration series with gradual additions of SiO2 was created. It was found that an increasing content of carbon in the steel significantly decreases the interfacial tension between the oxide system and the steel. The interfacial tension was found to decrease slightly with an increase in the content of SiO2 in the oxide system.Web of Science48341841

Anomalous diffusion on fractal structure of magnetic membranes

The concept of diffusion on fractal structure of polymeric membrane with magnetic powder is presented. The fractal characteristics, i.e. static fractal dimension df and fractal dimension of the trajectory of the random walk dw, were evaluated for qualitative and quantitative description of membrane structures. The way of introducing the fractal dimension and anomalous-diffusion exponent into the generalized diffusion equation on fractal geometries obtained by Metzler et al. has been shown. The results showed that the random walk within the membranes of the smallest granulation of magnetic powder was of the most subdiffusive character

Późne dyskinezy polekowe — rekomendacje grupy ekspertów

Późne dyskinezy polekowe, mimo stosowania w leczeniu now­szych leków neuroleptycznych, nie przestały być problemem klinicznym. W obrazie chorobowym dominują pląsawicze ruchy oromandibularne oraz polekowa dystonia, na przykład szyjna. Szczególne okoliczności terapeutyczne (np. konieczność konty­nuacji leczenia podstawowego schorzenia) powodują, że leczenie często jest mało skuteczne, szczególnie gdy objawy trwają zbyt długo. Celem przedstawionych rekomendacji interdyscyplinarnej grupy ekspertów jest przybliżenie spektrum objawów klinicznych, epidemiologii, patofizjologii i sposobów postępowania (farma­kologicznego, zabiegowego), ze szczególnym uwzględnieniem dostępnego od kilku lat w Polsce leku o nazwie tetrabenazyna