Catalytic partial oxidation (CPO) of hydrocarbons represents an interesting technology for hydrogen production on mobile systems. We investigated the CPO of 2,2,4-trimethyl pentane (iso-octane), chosen as surrogate for gasoline. CPO experiments were carried out in a laboratory scale autothermal reformer with honeycomb monolith catalysts (2% Rh/α-Al 2 O 3 ), equipped with probes for spatially resolved measurements of temperature and concentration. The iso-octane CPO process follows a reaction pathway which mainly consists of the exothermic combustion reaction and the endothermic steam reforming. The chemical reaction is very fast, and sharp gradients of temperature and concentration establish at the catalyst inlet. Similarly to the CPO of light hydrocarbons, the consecutive reaction mechanism results in the formation of a hot spot of temperature at the catalyst inlet. However, compared to light hydrocarbons, this phenomenology is specifically emphasized in the case of iso-octane, because of the higher overall exothermicity and the lower diffusion rate, which limits the steam reforming reaction rate. The reactor design strategy previously suggested in the CPO of methane, based on the enlargement of the channel opening to selectively limit the rate of oxygen consumption, does not work for the CPO of iso-octane where the consumption of the fuel is also considerably limited by mass transfer.
The rapidly growing use of digital control in Distributed Power Architectures (DPA) has been primarily driven by the increasing need of sophisticated Power Management functions. However, specifically designed control algorithms can also be exploited for optimizing the system performance. In this paper we present a new auto-tuning method and system that makes it possible to operate an isolated DC-DC converter at maximum efficiency. The auto-tuning performs an optimum adjustment of both primary side dead time and secondary side conduction times based on the measurement of the input current. It does not require any additional external components since current sensing functions are already implemented for power management purposes. Experimental measurements performed on an asymmetrical driven half-bridge DC-DC converter demonstrate the effectiveness of our solution and its robustness to component variations.
A study is presented on production, consumption, and the investment of profit in a closed economy over a two-week period. Bernard Schmitt's analysis of production and capital formation was applied to numerical and theoretical examples. The broad objective of this inquiry is to detect apparent formal coincidences between Nicholas Kaldor's (1956) formalization of the General Theory (1936) and the analytical formulation of the theory of the monetary circuit. Kaldor's (1956) model is considered as a special case among those contemplated by Schmitt's monetary theory.
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