Titanium alloys containing b stabilising elements such as Nb, Zr and Ta are particularly promising as implant materials because of their excellent combination of low modulus, high strength, corrosion resistance and biocompatibility. A low elastic modulus is important for implants to avoid stress shielding and associated bone resorption. The difficulty of producing complex shapes of these alloys by conventional methods makes metal injection moulding (MIM) attractive. Ti17Nb alloy parts with densities 94% of theoretical have been produced by MIM of a feedstock based on blended elemental powders. Scanning electron microscopy reveals a typical a2b Widmanstätten microstructure with a precipitated a phase layer along the grain boundaries. The parts exhibit an ultimate tensile strength of 768 MPa and a plastic elongation of over 5%. The modulus of elasticity, about 84 GPa, is more than 20% lower than that of cp Ti and Ti-6Al-4V.
Microcalorimetry and cloud point extrapolation indicate a lower critical solution temperature of 216 • C for poly(N,Ndimethylacrylamide) (PDMA). This is the highest phase-transition temperature in the poly(N,N-dialkylacrylamide) series. Cloud points were recorded from electrolyte solutions made of Na 3 PO 4 , CaCO 3 , (NH 4 ) 2 SO 4 and KOH. These measurements were realized below and beyond the boiling point of water. The hydrolytic properties of PDMA in superheated water (200 • C) were examined and verified using 1 H NMR analysis. The knowledge of the phase-transition temperature of pure PDMA is of interest, as it is often a constituent of smart copolymers, to adjust the responsiveness to a desired temperature threshold.
Wine lees are one of the main residues formed in vast quantities during the fermentation of wine. While toxic when applied to plants and wetlands, it is a biodegradable material, and several alternatives have been proposed for its valorization as: dietary supplement in animal feed, source for various yeast extracts and bioconversion feedstock. The implementation of stricter environment protection regulations resulted in increasing costs for wineries as their treatment process constitutes an unavoidable and expensive step in wine production. We propose here an alternative method to reduce waste and add value to wine production by exploiting this rich carbon source and use it as a raw material for producing carbon quantum dots (CQDs). A complete synthetic pathway is discussed, comprising the carbonization of the starting material, the screening of the most suitable solvent for the extraction of CQDs from the carbonized mass and their hydrophobic or hydrophilic functionalization. CQDs synthesized with the reported procedure show a bright blue emission (λmax = 433 ± 13 nm) when irradiated at 366 nm, which is strongly shifted when the wavelength is increased (e.g. emission at around 515 nm when excited at 460 nm). Yields and luminescent properties of CQDs, obtained with two different methods, namely microwave and ultrasound-based extraction, are discussed and compared. This study shows how easy a residue can be converted into an added-value material, thus not only reducing waste and saving costs for the wine-manufacturing industry but also providing a reliable, affordable and sustainable source for valuable materials.
A homologous series of biosurfactants has been synthesized by a novel sustainable biotransformation technique and compared with three other enzymatic processes. 6-O-Alkanoyl-methyl-a-D-glucopyranosides were obtained by lipase mediated esterification of methyl-a-D-glucopyranoside with capric acid C 10:0 , lauric acid C 12:0 , myristic acid C 14:0 , palmitic acid C 16:0 , and oleic acid C 18:1 . Solvent free transformations were compared with the use of ionic liquids and organic solvents. The lipase from Candida antarctica B, immobilized on macroporous acrylic acid beads (Novozyme 435), was employed either untreated or coated with small amounts of ionic liquids. This resulted in superior efficiencies (80%) with 1-butyl-4-methylpyridine hexafluorophosphate [4bmpy][PF 6 ] and broader substrate tolerance in comparison to solvent free transformation. The results show a positive correlation with increasing polarity of the ionic liquids used as liquid film-coating, which was in opposition to the use of the same ionic liquid as solvent. The analysis of the ionic liquid film coated catalyst carriers was performed by optical and scanning electron microscopy (SEM).
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