Coarsening to Chaos-Stabilized Fronts

We investigate a model for pattern formation in the presence of Galilean symmetry proposed by Matthews and Cox [Phys.\ Rev.\ E \textbf{62}, R1473 (2000)], which has the form of coupled generalized Burgers and Ginzburg-Landau-type equations. With only the system size $L$ as a parameter, we find distinct "small-$L$" and "large-$L$" regimes exhibiting clear differences in their dynamics and scaling behavior. The long-time statistically stationary state contains a single $L$-dependent front, stabilized globally by spatiotemporally chaotic dynamics localized away from the front. For sufficiently large domains, the transient dynamics include a state consisting of several viscous shock-like structures which coarsens gradually, before collapsing to a single front when one front absorbs the others.Comment: 4 pages, 7 figures; submitte

To prey or not to prey? Welfare and individual losses in a conflict model

We analyse a generalised form of the Hirshleifer-Skaperdas predation model. In such a model agents have a choice between productive work and appropriation. We suggest that such a model can usefully be thought of as a continuous form of the Prisoners' Dilemma. We present closed form solutions for the interior equilibria and comparative statics for all Cournot equilibria and analyse the social welfare losses arising from predation. We show that predation is minimised under two quite different regimes, one in which claiming is very ineffective and another in which one of the players becomes marginalised. The worst outcomes seem to arise when claiming is effective, but inequality in power is significant but not extreme. This, arguably, is the situation in a number of transition societies

Diels-Alder reaction of α-phellandrene and p-benzoquinone as an experiment for the organic chemistry teaching lab

https://openriver.winona.edu/urc2018/1130/thumbnail.jp

Potential of derived lunar volatiles for life support

The lunar regolith contains small quantities of solar wind implanted volatile compounds that have vital, basic uses for maintaining life support systems of lunar or space settlements. Recent proposals to utilize the helium-3 isotope (He-3) derived from the lunar regolith as a fuel for fusion reactors would result in the availability of large quantities of other lunar volatile compounds. The quantities obtained would provide the annual life support replacement requirements of 1150 to 23,000 inhabitants per ton of He-3 recovered, depending on the volatile compound. Utilization of the lunar volatile compounds for life support depends on the costs, in terms of materials and energy, associated with their extraction from the lunar regolith as compared to the delivery costs of these compounds from Earth resources. Considering today's conservative estimated transportation costs ($10,000 dollars per kilogram) and regolith mining costs ($5 dollars per ton), the life support replacement requirements could be more economically supplied by recovering the lunar volatile compounds than transporting these materials from Earth resources, even before He-3 will be utilized as a fusion fuel. In addition, availability of lunar volatile compounds could have a significant cost impact on maintaining the life support systems of the space station and a Mars base