Aliyah S. Zaman is currently a PhD student starting my second year of my research working within the area of biomaterial engineering. I have progressed rapidly with my research through hard work and dedication, and I am currently undertaking experiments as part of my PhD whilst writing paper for publication specifically relevant to my research. I support first year pharmacy students within their practical classes assisting with relevant calculations and the process required to produce certain products, alongside which I also mark their work and provide feedback.
The electrohydrodynamic atomisation (EHDA) technique is optimised for the production of uniform nanoparticles via the atomisation of liquids through the use of electrical forces (Haj-Ahmad et al., 2015). The EHDA technique is a single step process specifically used for the production of particles and fibers in the micro/nano range. It is possible to use this process for the encapsulation of drugs/actives within a polymeric matrix for release over time. The efficiency of particle engineering is affected by a number of factors namely the flow rate of polymeric solution, applied voltage and finally the distance between the nozzle and the collection plate. The electrospraying process gives rise to the production of nanoparticles (NPs) which can be used as particulate active matrix systems. The electrospraying process was deployed for polymers (PCL, PLGA and PMSQ) with varying hydrophobicities and was investigated to determine the impact of engineering parameters on the hydrophobic nature and outcome of polymer solutions. The physical properties of the polymeric solutions were characterised and these solutions were then sprayed using electrohydrodynamic atomisation (EHDA) and were analysed using optical and SEM. The spraying process was optimised using varying flow rates and applied voltages for each medium, these were found to be 80 µL/min and 13.2kV for PCL, 80 µL/min and 10.2kV for PLGA and 80 µL/min and 15.5kV for PMSQ. The process was observed using real time imaging (optical zoom camera and several jetting modes were observed). SEM showed the formation of spherical uniform particles for PCL, particles formed from PLGA also showed the formation of spherical particles however these had agglomerated appreciably and finally PMSQ displayed bowl shaped morphology after processing. It is possible to suggest both process parameters and the hydrophobic nature of the polymer play a part in topographical and morphological features of nanoparticles.
Andres Gonzalez-Hernandez has his expertise in material science. Ph.D, full time professor at the Metallurgical and Material Science at the Department at Universidad Industrial de Santander, Bucaramanga, Colombia. He received his B.Sc. in Metallurgical Engineering in the Universidad Pedagógica y Tecnológica de Colombia, Tunja, Colombia in 2004, his M.Sc. Engineering degree in 2008 and his Ph.D in Engineering at Universidad de Antioquia, in 2014 together with the degree Ph.D. in Ceramic Materials in Université de Limoges, France. His research interests include: thermal spraying coatings, thermal barrier coatings, plasma spraying coatings, microstructure, wear and flame spraying.
A high percentage of energy generation is made using gas turbines. These turbines have increased in efficiency due to protection systems such as thermal barrier coatings (TBCs). TBCs systems are widely used to provide thermal and corrosion protections for the metallic hot-section components to achieve extended the durability of a gas turbine. A typical TBC system is composed by MCrAlY (M=Ni and/or Co) metallic bond-coat as an oxidation resistant layer and the yttria stabilized zirconia (YSZ) topcoat as a thermal insulation layer. These coatings BCs are usually applied either by an atmospheric plasma spray (APS) or electron beam physical vapour deposition (EB-PVD). Suspension plasma spraying (SPS), as a newly emerged technique of thermal spraying processes, has been intensity investigated to elaborated ceramic coatings with bimodal structures (include nanostructures) obtained from its raw material. The hot corrosion behavior of 4.5 wt. % Yttria Stabilized Zirconia coatings was investigated in the presence of Na2SO4 and V2O5 and as corrosive molten salt for 40h at 1050ºC. The microstructure of the 4.5 YSZ coating showed that it was composed by a bimodal structure made of un-molten nanosized particles imbedded in a matrix of molten splats, which is a typical characteristic of this kind of coatings. The results of hot corrosion test showed that the molten salts at high temperature had a strong chemical reaction with the yttria (Y2O3) of the 4.5 YSZ coating generating its delamination. It was occurred in the ceramic layer due to the creation of stress resulting of these delamination. According to EDS- SEM analysis, the evaluation of surface of 4.5 YSZ coating showed mainly the formation of crystals composed by Y, V, O by interaction between of V2O5 of the salts and Y2O3 of the coating (Fig. 1).