No abstract

Ethanol steam reforming was studied over Ni supported catalysts. The effects of support (Al2O3, Al2O3–ZnO, and Al2O3–CeO2), metal loading, catalyst activation method, and steam-to-ethanol molar feed ratio were investigated. The properties of catalysts were studied by N2 physisorption, TPD-CO2, X-ray diffraction, and temperature programmed reduction. After activity tests, the catalysts were analyzed by TOC analysis. The catalytic activity measurements showed that the addition either of ZnO SSor CeO2 to alumina enhances both ethanol conversion and promotes selectivity towards hydrogen formation. The same effects were observed for catalysts with higher metal loadings. High process temperature and high water-to-ethanol ratio were found to be beneficial for hydrogen production. An extended catalyst stability tests showed no loss of activity over 50 h on reaction stream. The TOC analysis of spent catalysts revealed only insignificant amounts of carbon deposit.

No abstract

This paper describes an experimental and theoretical approach to evaluate cycloid drive reducer efficiency. The tests are carried out on 7.5 kW two-disc cycloid drive with a gear ratio of 19. The torque and speed are measured on the input and output shaft. The efficiency is calculated based on the obtained results. The main goal of the second part of the study is to deduce equations of cycloid reducer in order to predict and analyze experimental results. In this way, the following points are set for the simulation: a working condition in which the input speed and the output load are imposed; then, the output speed is determined by the gear ratio, and finally, the input torque is obtained by solving the dynamic problem. A new model for cycloidal reducers is proposed. This model is based on kinematics and dynamics of rigid bodies and a non-linear stiffness based on contact dynamics. The overall elasticity effects are all condensed between the input shaft and the cycloidal disk. The proposed model allows to predict the efficiency for several operational conditions and offer a drastic reduction of computational costs suitable for the optimization process.

No abstract