The Bayer Process (for alumina) as we know it today involves two steps: • The pressure leaching of bauxite with NaOH solution to obtain sodium aluminate solution. • The precipitation of pure aluminum hydroxide from this solution by seeding with fine crystals of Al(OH)3 . The leaching step was invented five years after the precipitation step (Table 1), and the precipitation step was an improveme...

An educational game simulating the first developments of a Martian base is presented. The user faces a satellite image of Mars and commands the astronauts. They can walk on the surface, drive a rover, extract ores, transform hydrogen and carbon dioxide in propellant, build a greenhouse, do farming, and so on. A user-friendly interface has been developed. The simulation looks like other well-kno...

Post-modernism and recent critical theory has sought to deconstruct the role of particular ‘Great Traditions’ and ‘Grand Narratives’ as privileged accounts of world affairs, contemporary and historical. In spite of this, such narratives, even if poorly understood, remain at the heart of much public debate and continue to shape national and global policies. These traditions, linked to elements o...

Abstract This paper contributes to a growing literature on state capacity with reference the early modern Asian empires. The historiography of these states, and especially Mughal empire South Asia, has moved away from an image unrestrained despotism towards that constrained state, but yet explore fully what constraints were did overcome them. Using new dataset conflicts in analytical model, sho...

Au début du xxe siècle, les communautés musulmanes d’Afrique Nord ont réagi à l’expansion impériale européenne de diverses manières. Comme le démontre cet article, la période entre l’invasion Maroc (1907) et guerre italo-turque (1911-1912) a vu une montée nouveaux réseaux politiques paramilitaires traversant frontières impériales. Ces réseaux, créés partir relations religieuses intellectuelles ...

The analysis of ancient human DNA from South America allows the exploration of pre-Columbian population history through time and to directly test hypotheses about cultural and demographic evolution. The Middle Horizon (650-1100 AD) represents a major transitional period in the Central Andes, which is associated with the development and expansion of ancient Andean empires such as Wari and Tiwana...

The Chinese tradition of supplementing large quantities of bronze cash with unminted gold and silver represents a rare exception to the western model of precious-metal coinage. This paper provides a detailed discussion of monetary development in ancient China followed by a brief survey of conditions in the Roman empire. The divergent development of the monetary systems of the Han and Roman empi...

In a chapter entitled “Spacious Skies and Tilted Axes” Jared Diamond (1997) argues that crops and domestic animals are spread more easily along lines of latitude (along an East-West axis) rather than along lines of longitude (along a North-South axis). Diamond suggests that East-West spread is easier because similar climates and soil types tend to be arranged in east-west oriented bands. Th is ...