Comparative study of the effect of fuel deoxygenation and polar species removal on jet fuel surface deposition

The effect of near-complete deoxygenation and polar species removal on deposition propensity of a Jet A-1 fuel type, with marginal thermal oxidative stability was studied in a laboratory scale approach. The fuel deoxygenation was carried out via nitrogen purging and two types of bespoke zeolites were used separately in a packed bed reactor for partial polar separation. The treated fuel samples were assessed individually for deposition propensity, using “High Reynolds Thermal Stability(HiReTS)” test device. It was found that when the concentration of hydroperoxides in fuel is relatively high, polar removal is more effective way than the fuel deoxygenation in reducing carbona- ceous deposits. Furthermore, competitive adsorption of dissolved O 2 with polar species was studied for a model fuel doped with a few polar species, as well as for the Jet A-1 with marginal thermal stability, in the packed bed reactor with zeolite 3.7Å. The polar species added to the model fuel share the same functional groups as those in Jet A-1 with a strong im pact on fuel thermal degradation and surface deposition. These include hexanoic acids, heaxnol, hexanal, hexanone, phenyl amine (aniline), butylated hydroxytoluene(BHT), dibutyl disulfide and Fe naphthenate. A one-dimensional model for calculation of dissolved O 2 adsorption in the packed bed reactor was built using COMSOL Multiphysics. The modelling results were in good agreement with the induction period prior to the beginning of the O 2 adsorption, as well as the different stages of O 2 uptake during the competitive adsorption between dissolved O 2 and polar species in the Jet A-1 fuel. The calculation showed a discrep- ancy with the experimental results beyond the second phase of O 2 adsorption. More theories, assumptions and physical sub-models are required to build a more robust pre- dictive model. A new chemical reaction pathway based on the self-reaction of hydroperoxides was proposed as part of “Basic Autoxidation Scheme(BAS)” to justify the relatively high deposition propensity of the marginal fuel after near-complete deoxygenation. The vi- ability of this reaction pathway was supported by the quantum chemistry calculations

Probing a Complex of Cytochromecand Cardiolipin by Magnetic Circular Dichroism Spectroscopy: Implications for the Initial Events in Apoptosis

Oxidation of cardiolipin (CL) by its complex with cytochrome c (cyt c) plays a crucial role in triggering apoptosis. Through a combination of magnetic circular dichroism spectroscopy and potentiometric titrations, we show that both the ferric and ferrous forms of the heme group of a CL:cyt c complex exist as multiple conformers at a physiologically relevant pH of 7.4. For the ferric state, these conformers are His/Lys- and His/OH–-ligated. The ferrous state is predominantly high-spin and, most likely, His/–. Interconversion of the ferric and ferrous conformers is described by a single midpoint potential of -80 ± 9 mV vs SHE. These results suggest that CL oxidation in mitochondria could occur by the reaction of molecular oxygen with the ferrous CL:cyt c complex in addition to the well-described reaction of peroxides with the ferric form

Effect of reactive sulfur removal by activated carbon on aviation fuel thermal stability

The effect of reactive sulfur removal from a Jet A-1 fuel with marginal thermal 3 stability on surface deposition propensity is reported. The sulfur removal was achieved 4 through adsorptive treatment the fuel with activated carbon.The treated fuel was as- 5 sessed for surface deposition propensity using a High Reynolds Thermal Stability(HiReTS)test 6 device. It was found that activated carbon has a strong adsorption capacity for removal 7 of reactive sulfur and Fe components from the fuel. This resulted in a substantial re- 8 duction of surface deposition propensity of the Jet A-1 fuel. 9 Density Functional Theory(DFT) was used to investigate the role of reactive sulfur and 10 Fe on thermal oxidative stability.Mechanistic pathways for intervention of these class 11 of species with hydroperoxides are proposed

Comparison of engagement and emotional responses of older and younger adults interacting with 3D cultural heritage artefacts on personal devices

The availability of advanced software and less expensive hardware allows museums to preserve and share artefacts digitally. As a result, museums are frequently making their collections accessible online as interactive, 3D models. This could lead to the unique situation of viewing the digital artefact before the physical artefact. Experiencing artefacts digitally outside of the museum on personal devices may affect the user's ability to emotionally connect to the artefacts. This study examines how two target populations of young adults (18–21 years) and the elderly (65 years and older) responded to seeing cultural heritage artefacts in three different modalities: augmented reality on a tablet, 3D models on a laptop, and then physical artefacts. Specifically, the time spent, enjoyment, and emotional responses were analysed. Results revealed that regardless of age, the digital modalities were enjoyable and encouraged emotional responses. Seeing the physical artefacts after the digital ones did not lessen their enjoyment or emotions felt. These findings aim to provide an insight into the effectiveness of 3D artefacts viewed on personal devices and artefacts shown outside of the museum for encouraging emotional responses from older and younger people