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Internal Combustion engines with multi-point, or sequential, fuel injection have a fuel injector for each cylinder, usually located so that they spray right at the intake valve. While in a fully warmed-up engine, fuel droplets vaporize before entering the combustion chamber, at cold start, a significant proportion of the injected gasoline deposits on the intake port and valve surfaces. The result is a deterioration of mixture homogeneity, decreased metering accuracy and increased hydrocarbon emissions. A better control of mixture preparation at cold start conditions can be achieved if the interaction between the gasoline spray and the time-varying liquid film which forms during the period of injection can be accurately predicted. The work reported here considers part of an experimental study performed with that objective in a purposed built experiment considering a simplified geometry.Droplet characteristics measured with a PDA system in the vicinity of the impact surface, prior and right after the impact, are used to infer about the transient spray-wall interaction mechanisms when a liquid film forms. Conservation laws allow to derive the fractions (α θ ) of mass, momentum and energy from the spray prior to impact that are transferred to/from the liquid film. Most of the inflowing mass deposits within the core of the spray and transfers momentum to the liquid film in the radial direction, influencing the velocity and direction of secondary droplets formed at impingement. The use of α θ , together with the mass flux ratio of outgoing to inflowing droplets in existing empirical correlations to predict the impingement outcome, is shown to improve prediction of flux ratios, either of number, momentum or energy. These fractions are suggested as a simple way of including the influence of the liquid film in spray/wall interaction and their modelling is the scope of future work. LFS SS ST LFS SS ST

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SYNOPSISFrontalis EMG biofeedback and diazepam treatments were compared in tension headache patients; headache scores (intensity and frequency) and frontalis EMG were used as control parameters. The study, conducted in a double blind manner, was split in three equal observation periods (4 weeks): baseline, treatment and follow-up. Four patient groups were chosen, two of which received placebo treatment. In both true conditions, biofeedback and diazepam, treatment effects differentiated from placebo groups; with diazepam the strongest results upon headache and frontalis EMG were observed during treatment, which, however, were lost at the follow-up period; biofeedback although with weaker effects during treatment showed, at follow-up, a long lasting reduction of headache scores even when frontalis activity reached baseline levels; in the false biofeedback group some decrease of EMG activity during treatment and of headache intensity at follow-up were also observed. The data suggest that biofeedback is a complex learning situation, where several uncompletely known factors are possibly at work; it also raises the possibility of a complex relation between frontalis muscular activity and headache since a simple linear relation of both variables was not observed. (Headache 22:216-220, 1982)