Ejecta Transfer in the Pluto System

The small satellites of the Pluto system (Styx, Nix, Kerberos, and Hydra) have very low surface escape velocities, and impacts should therefore eject a large amount of material from their surfaces. We show that most of this material then escapes from the Pluto system, though a significant fraction collects on the surfaces of Pluto and Charon. The velocity at which the dust is ejected from the surfaces of the small satellites strongly determines which object it is likely to hit, and where on the surfaces of Pluto and Charon it is most likely to impact. We also show that the presence of an atmosphere around Pluto eliminates most particle size effects and increases the number of dust impacts on Pluto. In total, Pluto and Charon may have accumulated several centimeters of small-satellite dust on their surfaces, which could be observed by the New Horizons spacecraft.Comment: 28 pages, 6 figures, accepted for publication in Icaru

Improving LMOF luminescence quantum yield through guest-mediated rigidification

Rotation of a specific pyridyl ring in LMOF-236 is locked by loading guest molecules into the MOF's pore, improving quantum yield by nearly 400%–an example of a generalizable strategy for maximizing quantum yield via guest-packing rigidification

Evaluation of actuator energy storage and power sources for spacecraft applications

The objective of this evaluation is to determine an optimum energy storage/power source combination for electrical actuation systems for existing (Solid Rocket Booster (SRB), Shuttle) and future (Advanced Launch System (ALS), Shuttle Derivative) vehicles. Characteristic of these applications is the requirement for high power pulses (50-200 kW) for short times (milliseconds to seconds), coupled with longer-term base or 'housekeeping' requirements (5-16 kW). Specific study parameters (e.g., weight, volume, etc.) as stated in the proposal and specified in the Statement of Work (SOW) are included

Land use in rural New Zealand: spatial land use, land-use change, and model validation

Abstract Land is an important social and economic resource. Knowing the spatial distribution of land use and the expected location of future land-use change is important to inform decision makers. This paper documents and validates the baseline land-use maps and the algorithm for spatial land-use change incorporated in the Land Use in Rural New Zealand model (LURNZ). At the time of writing, LURNZ is the only national-level land-use model of New Zealand. While developed for New Zealand, the model provides an intuitive algorithm that would be straightforward to apply to different locations and at different spatial resolutions. LURNZ is based on a heuristic model of dynamic land-use optimisation with conversion costs. It allocates land-use changes to each pixel using a combination of pixel probabilities in a deterministic algorithm and calibration to national-level changes. We simulate out of sample and compare to observed data. As a result of the model construction, we underestimate the “churn” in land use. We demonstrate that the algorithm assigns changes in land use to pixels that are similar in quality to the pixels where land-use changes are observed to occur. We also show that there is a strong positive relationship between observed territorial-authority-level dairy changes and simulated changes in dairy area