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https://hdl.handle.net/2440/17682
2024-03-19T03:16:02ZCation Inversion in Slag Magnetite: Energy Loss Measurements of Fe-L₃ Edge Shift between Atom Columns
https://hdl.handle.net/2440/140214
Title: Cation Inversion in Slag Magnetite: Energy Loss Measurements of Fe-L₃ Edge Shift between Atom Columns
Author: Gezzaz, H.; Ciobanu, C.L.; Slattery, A.; Cook, N.J.; Ehrig, K.
Abstract: Determination of cation disorder in inverse spinels like magnetite, Fe3O4, is of broad interest for applications in green technologies, storage devices, and nuclear waste management since cation distributions govern magnetic and electrical properties. Magnetite is a main component of slags produced by smelting of copper ores and contains potentially valuable trace elements. We address cation disorder as a factor controlling the behavior of these elements during atmospheric cooling from 1300 °C. To estimate cation disorder, we combine atomic-scale scanning transmission electron microscopy with electron energy loss spectroscopy. The inversion parameter (0.72) indicates minor partial ordering due to fast cooling from high temperature, resulting in skeletal textures. Trace element incorporation into magnetite, instead of exsolution of discrete nanoparticle phases is promoted. Our findings provide insights into the cooling behavior of spinels and facilitate robust thermodynamic modeling that addresses the stability of structures during cooling from melts. Findings carry implications for critical element recovery and prospects for transforming industrial waste into future resources.
Description: Available online 31 July 20232023-01-01T00:00:00ZSpatially offset optical coherence tomography: Leveraging multiple scattering for high-contrast imaging at depth in turbid media
https://hdl.handle.net/2440/139420
Title: Spatially offset optical coherence tomography: Leveraging multiple scattering for high-contrast imaging at depth in turbid media
Author: Untracht, G.R.; Chen, M.; Wijesinghe, P.; Mas, J.; Yura, H.T.; Marti, D.; Andersen, P.E.; Dholakia, K.
Abstract: The penetration depth of optical coherence tomography (OCT) reaches well beyond conventional microscopy; however, signal reduction with depth leads to rapid degradation of the signal below the noise level. The pursuit of imaging at depth has been largely approached by extinguishing multiple scattering. However, in OCT, multiple scattering substantially contributes to image formation at depth. Here, we investigate the role of multiple scattering in OCT image contrast and postulate that, in OCT, multiple scattering can enhance image contrast at depth. We introduce an original geometry that completely decouples the incident and collection fields by introducing a spatial offset between them, leading to preferential collection of multiply scattered light. A wave optics-based theoretical framework supports our experimentally demonstrated improvement in contrast. The effective signal attenuation can be reduced by more than 24 decibels. Notably, a ninefold enhancement in image contrast at depth is observed in scattering biological samples. This geometry enables a powerful capacity to dynamically tune for contrast at depth.2023-01-01T00:00:00ZInvestigations on the tribological behaviour, toxicity, and biodegradability of kapok oil bio-lubricant blended with (SAE20W40) mineral oil
https://hdl.handle.net/2440/138154
Title: Investigations on the tribological behaviour, toxicity, and biodegradability of kapok oil bio-lubricant blended with (SAE20W40) mineral oil
Author: Shankar, S.; Manikandan, M.; Karupannasamy, D.K.; Jagadeesh, C.; Pramanik, A.; Basak, A.K.
Abstract: Vegetable oil becomes a viable alternative to mineral or synthetic oils due to its biodegradable nature. In this work, one such vegetable-based non-edible oil (kapok oil) is blended with a mineral-based oil (SAE20W40) at 15 and 30% ratio (by volume), and its changes in thermal, tribological, and corrosive properties were evaluated. Four-ball tribometer is utilized to assess its dynamic friction coefficient and the wear scar diameter of the worn out area on the ball. Biodegradability and toxicity test of kapok oil were examined and compared with the palm and mineral oil through bacterial growth and brine shrimp assay methods, respectively. The results showed that the dynamic friction coefficient and specific wear rate of the blended oil were lesser than the mineral oil. The mineral oil produced a higher roughness average (Ra) value than that of the blended oil. Kapok oil shows an adequate tribological properties (anti-friction and anti-wear) in contrast to the other vegetable oils. Overall, kapok oil had a high biodegradability nature and lower toxicity than the mineral oil.
Description: Published online: 4 March 20212023-01-01T00:00:00ZTribology of Elastomers
https://hdl.handle.net/2440/138080
Title: Tribology of Elastomers
Author: Hakami, F.; Pramanik, A.; Basak, A.K.
Abstract: This book highlights the tribological behavior of elastomers by investigating the effect of operating variables such as, the applied load and the abrasive particle size, and the materials’ mechanical properties such as, tensile strength, elongation at break, hardness, and tear strength by the experimental, statistical and analytical methods. It is found that the wear mechanism is mostly friction wear, which is mixed with fatigue wear and abrading under higher applied loads or larger abrasives. The statistical method shows that the abrasive particle size has the highest contribution followed by the applied load on the wear process. Wear equation is developed to predict the wear rate considering the trends of the input variables.2022-01-01T00:00:00Z