The molecular dynamics of a series of biomedical poly(dimethylsiloxane)(PDMS)-based thermoplastic polyurethane nanocomposites (TPU) containing low and high aspect ratio organosilicates was investigated using broadband dielectric spectroscopy (DRS). The microphase separated morphology and degrees of separation, extensively characterized in a previous publication, were used to aid the interpretation of the molecular dynamics. Three relaxations were identified in dielectric spectra of the neat host TPU and nanocomposites over the measured temperature and frequency range: the low temperature process associated with local motion of the PDMS phase (a1), the higher temperature process which is associated with the mixed phase segmental motion (a2), and Maxwell –Wagner – Sillars (MWS) interfacial polarization (a3) process. The incorporation of organoclays has previously been shown to influence the morphology of these TPU systems, consequently affecting their dielectric behaviour. In this work the segmental relaxation time and temperature of ?1 , ?2 , and ?3 process of the TPU are significantly altered by the presence of the low aspect ratio organo -hectorite. These significant changes in the TPU dynamics were due to very strong interactions between the exfoliated organo-hectorite and the TPU matrix, with the low aspect ratio nanofiller effectively acting as an interfacial compatibilizer. The dielectric spectroscopy data confirmed the existence of phase mixing in the E5-325 TPU containing organo-hectorite.

The article describes the preparation and testing of optical properties of carbon quantum dots. optical properties were tested using a UV-VIS spectrophotometer and spectrometer. The maximum absorbance was determined in the range of ? ~377 to ~408nm. All solutions obtained showed an emission corresponding to the wavelength in the green light range. Furthermore, the effect of solution concentration on the optical properties of carbon quantum dots was investigated.

A Monte Carlo simulation code is developed for the study of neutron induced radiation damage in the materials which results from nuclear collision as well as reactions that create energetic recoil atoms of the host material or reaction creates. The aim of this work is to investigate the impact of the radiation damage in the iron by the neutron energy irradiation. The damage parameter used in the evaluation is displacement per atom DPA in material as a function of neutron energy. For this purpose, the simulations were carried out using the Monte Carlo transport code MCNP to calculate the DPA cross section for iron. It was determined that the maximum number of displaced atoms was approximately 1.73E-03 DPA.

Biodegradable metallic implants are revolutionized alternative materials currently being considered for orthopaedic and stents applications for the restoration and remodeling of defected or fractured hard tissues. Examples of biodegradable metals include magnesium, iron and zinc. Findings had revealed that magnesium and iron show high tendencies of being used as biodegradable metallic implant. However, premature loss of mechanical integrity, high hydrogen gas evolution of magnesium metal as well as slow degradation rate of iron below the clinical benchmark had hindered their applications. On the other hand, Zinc metal with near to ideal degradation rate suitable for orthopaedic application but poor mechanical properties compared to magnesium and iron metals has recently attracted research interest as potential candidate salvager of biodegradable metallic implants. This paper therefore, presents brief review of the current research progress on biodegradable zinc alloys and composites in relation to their processing routes for biomedical application. In addition, key existing and emerging strategies for mechanical properties improvement are highlighted. Processing technique, types and or proportion of alloying elements had been identified as center-hub control for improving mechanical properties of zinc metals. Deductions were made and strategies for further research work on biodegradable zinc alloys were suggested.

This article reports the investigation on the effect of ladle furnace slag replacement on the flexural strength of thin fly ash-based geopolymer. The thin fly ash/slag geopolymers were prepared with the replacement of various percentages of ladle furnace slag (0%, 10%, 20%, 30% and 40%) into fly ash geopolymers with dimension of 160 mm × 40 mm × 10 mm. The thin geopolymerwas synthesised using 12M sodium hydroxide (NaOH) solution with solid-to-liquid (S/L) ratio of 2.5 and Na2SiO3 /NaOH ratio of 4.0. The curing temperature and time of samples were 60°C and 6 hours respectively. The mechanical properties of thin geopolymers was revealed using flexural test after 28 days. Several characterisation tools have been used including Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) to correlate the flexural properties with the microstructure and phases of fly ash/slag geopolymers. Results obtained reported that a positive effect on flexural strength was observed with the increasing amount of slag. The thin fly ash geopolymers replaced with 40% of ladle furnace slag showed the highest flexural strength of 7.8 MPa. The rich CaO content in ladle furnace slag boosted the C-S-H gels formation which increased the flexural strength of thin geopolymers.

The objective of this study was to determine the mechanical, swelling, and thermal properties of nitrile butadiene rubber (NBR)/epoxidized natural rubber (ENR) composite for oil seal applications. The blend was prepared with different ENR content and different plasticizer type (paraffinic oil and dioctyl phthalate). The composites were prepared by open milling process where the different amount of ENR was added ranging from 0 to 20 phr. Test results showed that dioctyl phthalate provides better compression set, swelling, and aging properties than paraffinic oil. Physical properties were not affected by ENR content up to 20 phr. The most promising sample from the study contains NBR 80 phr, ENR 20 phr, and dioctyl phthalate as a plasticizer.