Some remarks on the concepts of Preferences and Freedom of choice.

No abstract available.

A model of linear chain submonolayer structures. Application to Li/W(112) and Li/Mo(112)

We propose a lattice gas model to account for linear chain structures adsorbed on (112) faces of W and Mo. The model includes a dipole-dipole interaction as well as a long-ranged indirect interaction. We have explicitly demonstrated that the periodic ground states depend on a competition between dipole-dipole and indirect interaction. The effect of temperature is studied within the molecular-field approximation. The numerical results show that for dipole-dipole interaction only, all long periodic linear chain phases are suppressed to low temperatures. However, when the long-range indirect interaction becomes important, the long-periodic linear chain phases start to fill up the phase diagram and develop a high thermal stability. Model parameters are chosen to reconstruct a sequence of long-periodic phases as observed experimentally for Li/Mo(112) and Li/W(112).Comment: RevTeX 9 pages + 5 Postscript figures (included), uses newdoc.sty (included), to be published in Surface Scienc

Selective Hydrogenation of Furfural to Furfuyl Alcohol Over Copper Magnesium Oxide

Furfural is a byproduct of biomass hydrolysis and novel means of utilizing this platform chemical are at the forefront of biofuel research. This project investigated many of the various and viable means of catalytic upgrading of furfural to other value-added chemicals, before ultimately exploring the conversion of furfural to furfuryl alcohol over a copper catalyst on a magnesium oxide support. Reasonable reaction conditions, mechanisms, and catalysts for the conversion of furfural to various products and platform chemicals exist, but no circumstance represents an obviously preferred method. The objective of this research project was to design and conduct experiments that characterize this catalyst and qualify its applicability for the selective hydrogenation of furfural to furfuryl alcohol. The catalyst was explored in terms of its conversion of furfural, selectivity to furfuryl alcohol, BET-surface area, reaction rate, and performance over time. It was found that the catalyst performs very well for the first five hours of reaction time with furfural conversion averaging 94% with selectivity of furfuryl alcohol around 75%. But, issues arose beyond the first few hours and the reaction rate dropped by as much as 75% over 26 hours as the catalyst deactivated. There was also a reaction of furfural on the surface of the catalyst led to plugging of the reactor after approximately 20 hours. This project is very relevant to the field of chemical engineering and biofuel research. As biofuel production increases, so will the production of furfural, and finding ways to utilize this chemical in both an economical and environmentally friendly manner will greatly impact the growth and relevance of biofuels in the upcoming years

LHDA 1000 impact assessment : impact assessment report

Summary in English.The purpose of this report is to present an impact assessment of two possible access routes to the Mohale Dam in Lesotho, namely the Western Access Road and the Least Cost Alternative Route. It is an academic work to demonstrate an adequate grasp of principles, methods and techniques appropriate to the assessment, termed LHDA 1000. The water resources of Lesotho are being exploited to augment the current supply to the PWV industrial area of the Republic of South Africa, in terms of the Lesotho Highlands Water Project. This project is being implemented in phases. Phase lA, currently being constructed, involves the damming of the Malibamatso River at Katse in the Maluti Mountains (Figure1), a transfer tunnel through the mountains, a hydroelectric power station at 'Muela in Lesotho, and a delivery tunnel under the Caledon River to the Ash River (a tributary of the Vaal River which feeds the primary PW impoundment, the Vaal Dam) in the South Africa