The production of ethanol has increased in United States and Brazil in recent years, because of incentives to reduce gas consumption. In Brazil, there is a big program to use ethanol both as a single fuel or an additive to gas. In US, the incentive is to use ethanol combined to gas in proportion...

It is known that cities are the engines of growth of the modern economy and society. Herewith we highlight the national and regional characteristics of urbanization as a global process. Somewhere the urbanization is stimulated, in China for example, somewhere it is limited, as we see in Russia....