UQ eSpace

Abstract

This study investigates the effect of adding an element to commercially pure titanium, particularly-stabilizing element.-stabilizers as alloying element for titanium are proven to exhibit suitable mechanical properties for biomedical applications such as orthopedic implants. The main objective of this research is to observe the effect of adding a selected alloying element, niobium (Nb) to pure titanium in terms of microstructure changes and the mechanical properties. There has been an ongoing research for Ti-Nb alloy with regards to it as a potential biomedical alloy. The adaptation of existing titanium alloy from aerospace application, Ti-6Al-4V has imposed neural disorders and adverse tissue effects due to cytotoxicity of aluminium (Al) and vanadium (V). The other concern is to find the solution to reduce the elastic modulus of existing titanium alloy. Several efforts have been done to sort these issues and Ti-Nb based materials have shown positivity in their passivity and low elastic modulus. Since then, the mechanical properties of binary Ti-Nb alloys have been investigated. In this project, pure titanium and three different composition of Ti-Nb samples are prepared (pure Ti, Ti-10Nb, Ti-20Nb and Ti-30Nb). These samples are manufactured via the concept of powder metallurgy, which involved mechanical die pressing and vacuum sintering. For microstructural investigations, the samples were taken for further surface finishing process, which includes cutting, mounting, grinding, polishing and etching. The microstructure of the samples are examined with optical microscope. In order to study their mechanical properties, series of compression tests and Vickers hardness tests were conducted. From the results, the samples have shown an evolution of alpha () and beta () phase where the concentration of phase increases with increasing Nb content. The compression tests have shown that the elastic modulus increases at 10% content Nb compared to pure titanium, followed by drastic decrease at Ti-20Nb and a slight increase at Ti-30Nb. Other mechanical properties are also examined such as the 0.2% offset yield stress, ultimate compressive stress (UCS), ductility and the modulus of resilience. Out of the samples being tested and analyzed, Ti-20Nb has a potential to be introduced as a biomaterial for implants.

Impact of Plasticizers on Lignin–Carrageenan Formulation Properties and on Phosphorus Release from a Coated Triple Superphosphate Fertilizer

“…The peaks in the range of 1450−1292 cm −1 are assigned to C−H scissoring and bending; the peak at 1250 cm −1 corresponds to C−O stretching of the alcohol group, and the peak at 1100−1060 cm −1 reveals the presence of the C− O−C ether group. 34 For LC, LCG, and LCP (200−2000) composite films, as expected, characteristic bands of lignin (2925, 2840, 1705 cm −1 ), carrageenan (923 cm −1 ), glycerol (3268, 1045 cm −1 ), and PEG (1060, 1100, 1250 cm −1 ) were all identified (Figure 2F−I). The intensity of the band observed at 3268 cm −1 tends to increase with the addition of plasticizers.…”

High-Loading Poly(ethylene glycol)-Blended Poly(acrylic acid) Membranes for CO2 Separation

“…This was due to the partial decomposition of the PEG and the carboxylate dehydration of the PAA. 19,37,38 The third weight loss step occurred above 300 °C owing to the main polymer chain structural decomposition of the PAA and PEG. 39 Particularly, the high PAA loading-based PAA/PEG blend membrane exhibited higher thermal stability at about 400 °C than the PEG-rich PAA/PEG blend membrane.…”

Biotinylated Photocleavable Semiconductor Colloidal Quantum Dot Supraparticle Microlaser

“…The small peaks at 2931 and 1410 cm −1 are from the symmetric stretching of C−H present in the biotin, and the C−H bending mode from the PEG chain in the ligand. 33,34 In addition to FTIR, the ζ potential of the functionalized SPs was obtained (Table 1). The ζ potential decreases to −44.1 mV after silica shell growth due to the presence of deprotonated silanol groups (SiO − ) 35 and then increases to −27.2 mV after the reaction with the PC-biotin ligand.…”