Cardiovascular diseases are the most distributed cause of death worldwide. Stenting of arteries as a percutaneous transluminal angioplasty procedure became a promising minimally invasive therapy based on re-opening narrowed arteries by stent insertion. In order to improve and optimize this method, many research groups are focusing on designing new or improving existent stents. Since the beginning of the stent development in 1986, starting with bare-metal stents (BMS), these devices have been continuously enhanced by applying new materials, developing stent coatings based on inorganic and organic compounds including drugs, nanoparticles or biological components such as genes and cells, as well as adapting stent designs with different fabrication technologies. Drug eluting stents (DES) have been developed to overcome the main shortcomings of BMS or coated stents. Coatings are mainly applied to control biocompatibility, degradation rate, protein adsorption, and allow adequate endothelialization in order to ensure better clinical outcome of BMS, reducing restenosis and thrombosis. As coating materials (i) organic polymers: polyurethanes, poly(ε-caprolactone), styrene-b-isobutylene-b-styrene, polyhydroxybutyrates, poly(lactide-co-glycolide), and phosphoryl choline; (ii) biological components: vascular endothelial growth factor (VEGF) and anti-CD34 antibody and (iii) inorganic coatings: noble metals, wide class of oxides, nitrides, silicide and carbide, hydroxyapatite, diamond-like carbon, and others are used. DES were developed to reduce the tissue hyperplasia and in-stent restenosis utilizing antiproliferative substances like paclitaxel, limus (siro-, zotaro-, evero-, bio-, amphi-, tacro-limus), ABT-578, tyrphostin AGL-2043, genes, etc. The innovative solutions aim at overcoming the main limitations of the stent technology, such as in-stent restenosis and stent thrombosis, while maintaining the prime requirements on biocompatibility, biodegradability, and mechanical behavior. This paper provides an overview of the existing stent types, their functionality, materials, and manufacturing conditions demonstrating the still huge potential for the development of promising stent solutions.

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As there is a broad range of constructive features and � more important � operating conditions regarding calciners that are used in clinkering plants, CFD simulations could be an effective tool in increasing their performance. A methodology that could be used to optimize their functioning is given here. In brief, CFD simulations are carried out both for computing the average gases velocity at their passage through the calciner and visualize exactly the flow patterns within the vessel. By properly adjusting dimensional and design features with the known outputs from the neighboring apparatus and with the required retention time of the particles in the calciner corresponding to a given decarbonation degree one could reach high running efficiency with low energy loses, without the need for demanding and expensive live trials.

Protecting the environment by reducing PET waste has become a global priority. Recycling is considered one of the simplest and most environmentally friendly ways to reduce PET waste. However, during recycling, PET undergoes thermal / hydrolytic degradation, which leads to reduced molecular weights and low physical, mechanical, chemical, etc. properties. Thus, in order to prevent the degradation processes and to improve the mechanical and processing properties, various blends based on PETr / HDPE (60: 40 mass ratio) will be processed on a Brabender mixer in the presence / absence of the compatibilizers, EVA and PEg AM. The diagrams of torque versus time, recorded during processing demonstrate that PETr suffers degradation processes, which leads to a decrease in torque due to reduced viscosity /molecular weight and reduced physical-mechanical and processing properties. Instead, with the addition of EVA or PEg AM , in varying amounts, degradation processes are largely avoided. These observations are also supported by the values obtained from the Izod impact resistance tests, namely the higher the amount of compatibilizer, the higher the shock resistance due to the higher phase adhesion. The hardness of the blends progressively decreases, relative to the PETr control sample value, from 83 to at least 61°Sh D for the compatibilized blends. FTIR microscopy, performed on the obtained samples, shows higher homogeneity between PETr / HDPE if the addition of EVA or PEg AM is higher (20%). Melt flow index is improved for compatibilized blends compared to PETr and PETr / HDPE.

Alumina ceramics were obtained from three different alumina sources, A1–A3, with various rare-earth dopants (La2O3–La, Nd2O3–Nd, and Y2O3–Y), concentration levels (500 and 1000 ppm) and synthesizing routes (1500 °C, 1815 °C and cold plasma-P). Absorption (A) and density (ρ in text, rho in images) were measured, resulting in a complex, multivariate database. Principal Component Analysis (PCA) was run with the aim of deducing relationships between variables (alumina source, dopant level, thermal processing route, A and ρ), observations, and between variables and observations. A total of 206 Scanning Electron Microscopy (SEM) micrographs were recorded at various scales and the corresponding images were processed to quantify the microstructural features. Two techniques of edge detection were used; Fractal Dimension (FD) was calculated for each micrograph and results were compared. Various scales of the micrographs prevented us from using any other approach, such as simply measuring the grains or obtaining shape parameters. The initial database was extended by including FDs and PCA was run again. We found that plasma processing is positively correlated to A and negatively correlated to both temperature (T) and ρ; La ceramics have an opposite behavior to Y and Nd ceramics. FD successfully explained observations being correlated, mainly, to Y, Nd and, to a lesser extent, to La. FD proved that it is a reliable and simple approach to quantifying microstructural features when comparing highly different, noisy micrographs.