Advances in Electrospun Nanofibers

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Increased growth rate of anodic porous alumina by use of ionic liquid as electrolyte additive

The use of ionic liquids 1-Butyl-3-methylimidazolium 2-(2-methoxyethoxy) ethyl sulfate and 1-Butyl-3-methylimidazolium tetrafluoborate has been tested in the fabrication of anodic porous alumina. The anodizations of the aluminium substrate have been carried out in oxalic acid in galvanostatic mode. During anodization with 1-Butyl-3-methylimidazolium tetrafluoborate added electrolyte, proper tuning of the current density and of the additive concentration resulted in a three-fold increase of the growth rate as compared to the bare acidic solution with the same acid concentration. This did not cause cracks in the film during growth, and did not affect the regular structure of the pores at the interface with the substrate

FLOATING MULTIPLE UNIT MINITABLETS OF METOPROLOL SUCCINATE: FORMULATION, IN VITRO AND IN VIVO CHARACTERIZATION

Objective: In this present research, formulation of floating multiple unit minitablets of metoprolol succinate without using gas generating agent was attempted with an objective of increased residence time, sustained release, and improved oral bioavailability. Methods: Solid dispersions were prepared with lipophilic carriers such as compritol ATO888, Gelucire 43/01, Gelucire 39/01, and precirol ATO 05 was formulated using fusion technique. Neusillin US2 was used as an adsorbent. The solid dispersions were compressed into minitablets, weighing 20 mg, and then filled into ‘0’ size capsule. Results: Formulation F9, F10, F14, and F15 showed instantaneous floating lag time, i.e., 0 min, floating time more than 12 h, and sustained release up to 12 h. Pharmacokinetic study of the optimized formulation (F9) showed 2.46 times increase in area under the curve with increased residence time. Conclusion: Hence gelucire 43/01 based floating multiple unit minitablets of metoprolol succinate can be considered a promising approach

Oxidation behaviour of SiC/SiC ceramic matrix composites in air

Oxidation of silicon melt infiltrated SiC/SiC ceramic matrix composites (CMC) was studied in air at 1200–1400 °C for 1, 5, 24 and 48 h. Weight gain and oxide layer thickness measurements revealed the oxidation follows parabolic reaction kinetics with increase in temperature and time. XRD showed the extent of oxide layer (SiO2) formation was greatest after 48 h at 1400 °C: an observation confirmed by X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM) analyses. Oxide layer thickness varied from 1 μm after 48 h at 1200 °C to 8 μm after 48 h at 1400 °C. Oxidation of SiC/SiC composites is both temperature and time dependent with an activation energy of 619 kJ mol−1. BN coatings around SiC fibres showed good resistance to oxidation even after 48 h at 1400 °C

Use of Ionic Liquid in Fabrication, Characterization, and Processing of Anodic Porous Alumina

Two different ionic liquids have been tested in the electrochemical fabrication of anodic porous alumina in an aqueous solution of oxalic acid. It was found that during galvanostatic anodization of the aluminum at a current density of 200 mA/cm2, addition of 0.5% relative volume concentration of 1-butyl-3-methylimidazolium tetrafluoborate resulted in a three-fold increase of the growth rate, as compared to the bare acidic solution with the same acid concentration. This ionic liquid was also used successfully for an assessment of the wettability of the outer surface of the alumina, by means of liquid contact angle measurements. The results have been discussed and interpreted with the aid of atomic force microscopy. The observed wetting property allowed to use the ionic liquid for protection of the pores during a test removal of the oxide barrier layer