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The combination of high boosting and high exhaust gas recirculation (EGR) is a practical and effective strategy to achieve simultaneous reductions of fuel consumption and exhaust emissions in diesel engines. To obtain further improvements of fuel efficiency and emissions, the effects of engine parameters including compression ratio, peak cylinder pressure, and the timing of the start of combustion are investigated using a single-cylinder diesel engine under conditions of high boost pressure of 400 kPa and fuel injection pressure of 200 MPa, focusing particularly on the peak cylinder pressure. The experiments show that when the peak cylinder pressure is raised to 28 MPa by adjusting the timing of the start of combustion at 23°after top dead centre (ATDC) at a compression ratio of 18, the lowest specific fuel consumption rate of 185.6 g/kW h, which corresponds to the brake thermal efficiency of 45.2 per cent, is obtained. When the effective compression ratio is lowered by using a variable valve timing system while maintaining the peak cylinder pressure at 28 MPa, the minimum specific fuel consumption of 181.2 g/kW h, which corresponds to a brake thermal efficiency of 46.3 per cent, is obtained.

The absorption of dilute CO 2 into aqueous solutions of sterically hindered 2-methyl aminoethanol (MAE) and the desorption of CO 2 from CO 2 -loaded MAE solutions into N 2 stream were investigated separately for the various combinations of operational variables, using a hydrophobic microporous hollow fiber (polytetrafluoroethylene, PTFE) contained gas-liquid contactor with aqueous solutions of MAE as liquid media in the shell side at 30 C. The absorption of CO 2 in this contactor is governed by resistance in the liquid and hollow fiber phases. The resistance to diffusion in the hollow fiber phase amounts to 76-80% of the total resistance. Nevertheless, the absorption rates of CO 2 into aqueous MAE solutions in this contactor are higher than those into aqueous solutions of sterically hindered 2-amino-2-methyl-1-propanol (AMP) in the stirred tank with a plane unbroken gas-liquid interface. The process of desorption of CO 2 from CO 2 -loaded MAE solutions can be regarded as being controlled by diffusion and chemical reaction in both the stagnant film of the liquid phase and the liquid-filled pore of the hollow fiber phase under the slow or intermediate reaction regime. Both absorption and desorption rates under the simultaneous absorption-desorption operation in a single unit tend to approach the respective constant values as process time elapses. The total absorption rate here seems to be almost balanced with the total desorpion rate at the constant mass transfer rate periods.

Abstract. We investigate the plasma dynamics during coalescence of two parallel current loops in solar flares by using a resistive three-dimensional MHD simulation code, paying particular attention finding the most effective electromagnetic fields for the production of high-energy protons. Next we investigate the orbit of many protons in the electromagnetic fields obtained from the MHD simulations. We investigate two cases of the coalescence process: (1) co-helicity reconnection where only the poloidal magnetic field produced from the axial currents dissipates and (2) counter-helicity reconnection where both poloidal and axial magnetic fields dissipate. We found a bump-on-tail distribution in the same direction as the original loop current for both the cases of co-helicity and counter-helicity. It is shown that the maximum proton energy exceeds the energy (2.223 MeV) of the observed prompt nuclear de-excitation lines of gamma-ray, and that proton energy spectrum is neither a pure power-law type nor a pure exponential type. We may conclude that anisotropic proton acceleration along the loop can be realized both for co-helicity and counter-helicity reconnection during the coalescence of two parallel loops.