https://ogma.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:55182 Wed 24 Apr 2024 09:41:14 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:46021 2AlC purity. Aside from a thin oxide layer on the coating surface, a pure Ti₂AlC layer was formed immediately below. In total, the coatings were found to exist as seven microstructurally unique sub-layers due to equilibration of supersaturated phases formed during the laser cladding process. No delamination between any layers was observed. The phase identification and microstructure, as determined using XRD, SEM and EDS, are described in detail. Some unique microstructures were observed, including dendritic Ti₂AlC MAX phase grains produced from a topochemical reaction between TiC_x and Ti_yAl_z regions, and α-Ti supersaturated with up to 33 at.% C. The kinetically trapped phases produced within the coating using this process may offer a strong combination of material properties which could be advantageous for use in extreme environments.]]> Wed 09 Nov 2022 15:31:01 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:54466 Tue 27 Feb 2024 13:57:41 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:52541 Tue 17 Oct 2023 10:11:41 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33787 Tue 15 Jan 2019 12:15:49 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:44144 Tue 14 Nov 2023 14:55:45 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:39087 2AlB₂, using a combination of experimental characterization and first-principles calculations. We find that Fe₂,AlB₂ is more tolerant to radiation-induced amorphization than MoAlB, both at 150 ℃ and at 300 ℃. The results can be explained by the fact that the Mo Frenkel pair is unstable in MoAlB and as a result, irradiated MoAlB is expected to have a significant concentration of Mo_Al antisites, which are difficult to anneal even at 300 ℃. We find that the tolerance to radiation-induced amorphization of MAB phases is lower than in MAX phases, but it is comparable to that of SiC. However, MAB phases do not show radiation-induced cracking which is observed in MAX phases under the same irradiation conditions. This study suggests that MAB phases might be a promising class of materials for applications that involve radiation.]]> Tue 14 May 2024 09:12:30 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34399 Tue 05 Mar 2019 13:21:55 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:31950 3. The effects of particle size variation on compressive strength, effective elastic modulus, and modulus of toughness were investigated. An upper and a lower bound were estimated for the elastic modulus of particles in EP/epoxy foams. EP/epoxy foams showed Reuss-like behaviour similar to metals but atypical of non-plastic materials. In addition, results illustrated the significant contribution of the expanded perlite particles in the effective elastic modulus of the foams. Micro-structure of expanded perlite particles was examined and related to their macroscopic properties via two geometrical relationships. Post-test microscopic observations coupled with macroscopic observations taken during the test were used to understand the effect of particle size on the behaviour of the foams under compressive load. Observations revealed the presence of three different failure modes for all foams regardless of their particle size and density; however, the strain to activate each mode was different for each foam type.]]> Tue 04 Dec 2018 15:00:47 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34033 Tue 03 Sep 2019 18:30:23 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:35304 Thu 11 Jul 2019 16:16:19 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:53741 Thu 11 Jan 2024 12:14:59 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:35552 Thu 10 Nov 2022 12:45:10 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:39269 Thu 02 Jun 2022 14:37:31 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:1344 Sat 24 Mar 2018 08:32:41 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:12117 Sat 24 Mar 2018 08:11:02 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17271 Sat 24 Mar 2018 08:01:22 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21122 Sat 24 Mar 2018 07:54:02 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:18534 Sat 24 Mar 2018 07:50:11 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:5241 Sat 24 Mar 2018 07:44:19 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26124 n+1AX_n phases to systems where the element 'A' is not the reducing agent was investigated in systems TiO₂-A-Al-C for A=Al, Si, Ga, Ge, In and Sn as well as Cr₂O₃-Ga-Al-C. MAX phase-Al2O3 composites were made in all systems except those with A=Ga or In. The effectiveness of conversion to MAX phases was generally in the range 63-96% without optimisation of starting ratios. Optimisation in the Ti-Si-C system gave a MAX phase component with >98% Ti₃SiC₂.]]> Sat 24 Mar 2018 07:41:07 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:27300 Sat 24 Mar 2018 07:38:34 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:23991 R) and Richardson constants (Α_R) were determined using a Schottky diode arrangement at temperatures ranging from 1223 to 1473 K. Work functions ranged from 2.67 eV to 3.32 eV with a shallow minimum at 40% by mass W and were relatively constant (~2.7-2.8 eV) in the range 30-70% by mass W. The decrease in work function was accompanied by a strong decrease in A_R from 39.3 A cm⁻² K⁻² to 0.02 A cm⁻² K⁻² over the range 20-70% by mass W. The reduction in both φ_R and A_R was associated with the major conversion of the surface to BaWO₄ and Ba₄Ti₁₂O₂₇ during the activation treatment before emission testing.]]> Sat 24 Mar 2018 07:10:24 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:38283 xWO₃) are non-stoichiometric metal oxides which have attracted interest for their potential applications in plasmonics. Although the cubic structures of the sodium tungsten bronzes (Na_xWO₃) have been extensively studied, reports into the tetragonal-II structures (TII-) of any tungsten bronze are comparatively rare. In this work, TII-Na_xWO₃ and TII-K_xWO₃ were prepared by a furnace-assisted method, and characterised by X-ray and neutron powder diffraction, selected-area electron diffraction and electron energy-loss spectroscopy (EELS). A structural determination of TII-NaxWO3 was performed in the space group >I4∕m, in a √2 ✕ √2 ✕ 2 supercell of the P4∕mbm TII-K_xWO₃ structure. Density functional theory is then used to calculate the valence electronic structure and optical properties to support the EELS measurements. Similar to the cubic structures, the conduction band of TII- is composed of hybridised O 2p and W 5d states, which is filled by electrons donated from the inserted Na or K. The O sites which are in-plane with the W sites are found to have highly localised bands, resulting in low-energy interband transitions in the a∕b direction of the unit cell. In contrast, purely free-electron behaviour is observed in the c-direction below 2 eV. High-quality plasmon resonances are thus only observed in the c-direction, with energy and quality similar to those of the cubic structures. These anisotropic optical properties make TII-Na_xWO₃ and TII-K_xWO₃ interesting materials for further study as potential plasmonic materials.]]> Mon 29 Jan 2024 18:47:32 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:46799 Mon 29 Jan 2024 18:41:29 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47660 2, readily attaining surface temperatures of 520–530 °C, well above the phase change temperature of 420 °C. Single step charging led to a state of charge of 80% without exceeding a nominal surface temperature of 530 °C. Cycling on and off sun in the range 460–520 °C was used to achieve a state of 99% charged. Thermal performance of the MGA during solar charging and its discharge by natural cooling is presented and analysed.]]> Mon 29 Jan 2024 17:43:40 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:53915 Mon 22 Jan 2024 16:13:41 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:48507 4C₃ which would diminish the amount of Al available to act as a PCM. This work presents the effects of extended thermal cycling over the intended use range to test its effect on integrity, phase composition and microstructure of the two candidate materials. A small initial mass loss from the 5 g samples due to the loss of metal particles directly in contact with the surface was observed and which had stabilised after 50–100 cycles. The mass loss is accompanied by a small thermal capacity loss in DTA which also stabilised in the first 50–100 cycles. Both the mass loss and capacity reduction are expected to be greatly reduced in full scale storage modules due to the much smaller surface area to volume ratio (∼0.1) compared with that for the samples used here (∼4). The absence of X-ray diffraction peaks from the carbide Al₄C₃ in data from the cycled materials and their continued strong latent heat DTA signal strongly suggest that the materials are suitable for long-term use in thermal energy storage applications.]]> Mon 20 Mar 2023 16:11:23 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:40763 Mon 18 Jul 2022 14:01:39 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:45838 Mon 07 Nov 2022 13:56:03 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:45837 Mon 07 Nov 2022 13:49:17 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:46880 Mon 05 Dec 2022 14:06:41 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:41733 Fri 12 Aug 2022 13:20:32 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17273 Fri 10 Nov 2023 16:00:41 AEDT ]]>