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Gearing cities towards a path of sustainability is a daunting task. The urban models that we have come to accept during the 20th century need to be revisited, but change, even if welcomed in abstract, is usually met in reality with enormous resistance from the economic and political models that underlie our cities. Some of the most powerful tools for promoting change are those related to conceptualization and visualization. When considering urban plans that aren't just incremental improvements over what already exists, city officials, urban planners and the general public must be able to visualize not just the merits of those plans in isolation, but how they interact with all the infrastructure that already exists. This paper describes one such urban plan that has been under consideration in the city of Uppsala, Sweden, for the past 5 years: a solar-powered Personal Rapid Transit (PRT) system connecting the main train station to the Hospital and the University. The process of discussing the PRT system included the development of a virtual reality simulation of parts of the city. We report on the process and role of this virtual reality simulation. [ABSTRACT FROM AUTHOR]

The aim of this work was to evaluate the potential of Eucalyptus globulus hemicelluloses, mainly xylan, for bioethanol production. Hemicelluloses have been removed prior to pulping by auto-hydrolysis and an acid-catalysed hydrolysis. As the hydrolysates obtained were rich in xylose, the yeast Pichia stipitis was selected for fermentation. It was confirmed that the yeast performance is strongly dependent on pH and the presence of inhibitors, such as lignin. The addition of Ca(OH)2 was successful for lowering the concentration of inhibitors and adjusting the pH. The strain was grown in culture media with increasing volumetric percentages of treated hydrolysates up to 100% (v/v), supplemented with nutrients other than the carbon and energy source. This methodology shortened the lag phase of fermentation and improved the performance of yeast. Maximum ethanol concentration (12 geth l-1), productivity (0.22 geth l-1 h-1), and yield (0.48 geth gxyl eqs-1) were achieved with treated acid-hydrolysates. These results are similar to those obtained by a synthetic medium with an equivalent xylose concentration. [ABSTRACT FROM AUTHOR]