Constrained reaction coordinate (Bluemoon) dynamics have been used to characterise the free energy proÐle of benzene in silicalite-1 at 300 K along the mean reaction path for di †usion. The reaction path was found empirically by Ðtting a parametric curve through the mean positions of the benzene centre of mass. Both rigid and Ñexible zeolite lattices have been investigated. In both cases the primary adsorption site was located at the intersection of the straight and sinusoidal channels. Two other distinct adsorption sites exist in the straight channel and four in the sinusoidal channel. Lattice Ñexibility was found to have a very strong inÑuence on the relative free energies of the adsorption sites and on the free energies of the transition states connecting them. The free energies, combined with estimates of the transmission coefficient, i, were used to obtain rate constants for di †usion between the main adsorption sites in the Ñexible lattice. Subsequent di †usive Monte Carlo simulations, using these parameters, provided the self-di †usion coefficient, D, and its components, at 300 K. We obtained D \ 3.36 ] 10~14 m2 s~1, in excellent accord with the best experimental value of 2.2 ] 10~14 m2 s~1. Di †usion was fastest in the Y direction with the and D yy /D xx \ 1.49 D yy /D zz \ 5.65 being observed.

Ten simulations were performed with the HIGRAD/FIRETEC wildfire behaviour model in order to explore its utility in studying wildfire behaviour in inhomogeneous topography. The goal of these simulations is to explore the potential extent of the coupling between the fire, atmosphere, and topography. The ten simulations described in this paper include five different topographies, each run with two different ambient wind speeds of 6 and 12 m s–1. The five topologies explored are: an idealised hill (which serves as the base centerline for the other topographies), two variations of the hill with lateral gradients downwind from the ignition line (one sloping up from the ‘hill’ at the centerline to form an upward sloping canyon parallel to the ambient wind, and the other sloping down from the centerline to form a ridge parallel to the ambient flow), one with a second hill upwind of the ignition line such that the fire is ignited in the bottom of a canyon that runs perpendicular to the ambient wind, and finally a flat terrain. The four non-trivial topographies have the same profile along the centerline downwind of the ignition line to help assess the impacts of topographic gradients that are perpendicular to the ambient wind. It is hoped that analysis of these simulations will help reveal where point-functional models are sufficient, where topographically modified wind fields are needed, and where fully coupled fire and transport models are necessary to properly describe wildfire behaviour.

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The laboratory photolysis of chlorine nitrate (ClONO2) with 302.5 nm ultraviolet light leads to the destruction per quantum of 4 molecules of ClONO2 and the formation of 1 molecule of O2, 2 of Cl2 and 2 of N2O5. These quantum yields are not consistent with the current assumption that the primary photolysis step for ClONO2 in the stratosphere leads to the formation of ClO plus NO2. A consistent mechanism exists in which the photolytic step involves the decomposition of ClONO2 to ClONO + O(³P). The onset of observed absorption of radiation by ClONO2 corresponds approximately to the thermodynamic accessibility of this simple splitting away of an O atom. The photolysis of ClONO occurs very rapidly in the stratosphere, either to Cl + NO2 or ClO + NO. The substitution of either Cl + NO2 + O or ClO + NO + O for ClO + NO2 as the eventual photolysis products from ClONO2 is not expected to cause appreciable alteration in predictions from stratospheric modeling.

The Advance Mirror Technology Development (AMTD) project is a three year effort initiated in FY12 to mature by at least a half TRL step six critical technologies required to enable 4 to 8 meter UVOIR space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD uses a sciencedriven systems engineering approach. We mature technologies required to enable the highest priority science AND result in a high-performance low-cost low-risk system. To provide the science community with options, we are pursuing multiple technology paths. We have assembled an outstanding team from academia, industry, and government with extensive expertise in astrophysics and exoplanet characterization, and in the design/manufacture of monolithic and segmented space telescopes. A key accomplishment is deriving engineering specifications for advanced normalincidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicles and their mass and volume constraints.