h i g h l i g h t sAmmonia can become a new energy vector for large scale power generation. Ammonia fuelled gas turbines have been barely studied. Scarce literature exist. Current research provides findings that show NH 3 potential as gas turbines fuel. Unfortunately, weak flame stability and high emissions are still restrictive. Stratified injection with low swirl might be the best way to use these blends. a b s t r a c tAmmonia has been proposed as a potential energy storage medium in the transition towards a lowcarbon economy. This paper details experimental results and numerical calculations obtained to progress towards optimisation of fuel injection and fluidic stabilisation in swirl burners with ammonia as the primary fuel. A generic tangential swirl burner has been employed to determine flame stability and emissions produced at different equivalence ratios using ammonia-methane blends. Experiments were performed under atmospheric and medium pressurised conditions using gas analysis and chemiluminescence to quantify emission concentrations and OH production zones respectively. Numerical calculations using GASEQ and CHEMKIN-PRO were performed to complement, compare with and extend experimental findings, hence improving understanding concerning the evolution of species when fuelling on ammonia blends. It is concluded that a fully premixed injection strategy is not appropriate for optimised ammonia combustion and that high flame instabilities can be produced at medium swirl numbers, hence necessitating lower swirl and a different injection strategy for optimised power generation utilising ammonia fuel blends.

Purpose: To test the theoretical benefits of a spectral attenuated inversion-recovery (SPAIR) fat-suppression (FS) technique in clinical abdominal MRI by comparison to conventional inversion-recovery (IR) FS combined with T2-weighted (T2W) partial Fourier single shot fast spin echo (SSFSE).Materials and Methods: 1.5T MRI studies of the abdomen were performed in 28 patients with liver lesions (hemangiomas n ϭ 14; metastases n ϭ 14). T2W sequences were acquired using IR and SPAIR SSFSE. Measurements included retroperitoneal and mesenteric fat signal-to-noise (SNR) to evaluate FS; liver lesion contrast-to-noise (CNR) to evaluate bulk water signal recovery effects; and bowel wall delineation to evaluate susceptibility and physiological motion effects.Results: SPAIR-SSFSE images produce significantly improved FS and liver lesion CNR. The mean SNR of the retroperitoneal and mesenteric fat for SPAIR SSFSE was 20.5 Ϯ 10.2 (Ϯ1 SD) and 12.7 Ϯ 6.2, compared to 43.2 Ϯ 24.1 (P ϭ 0.000006) and 29.3 Ϯ 16.8 (P ϭ 0.0000005) for IR-SSFSE. SPAIR-SSFSE images produced higher CNR for both hemangiomas CNR ϭ 164 Ϯ 88 vs. 126 Ϯ 83 (P ϭ 0.00005) and metastases CNR ϭ 75 Ϯ 27 vs. 53 Ϯ 19 (P ϭ 0.007). Bowel wall visualization was significantly improved using SPAIR-SSFSE (P ϭ 0.002). Conclusion:The theoretical benefits of SPAIR over conventional IR FS translate into significant multiple improvements that can be measured on clinical abdominal MRI scans.

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