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This discussion paper is/has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP if available. Abstract We use 2009–2011 space-borne methane observations from the Greenhouse Gases Observing SATellite (GOSAT) to constrain global and North American inversions of methane emissions with(More)
The Virginia Tech HokieSat is part of an Air Force initiative for students to design and build satellites. The mission requires an attitude determination and control system (ADCS) that provides adequate control of the spacecraft within a satellite formation , despite its relatively small size and constrained budget, while minimizing power use during flight(More)
[1] Providing top-down constraints on emissions is an important application of model-based analysis of remote-sensing observations of chemically reactive species, yet the degree to which column concentrations are governed by local vs distant sources within models themselves has yet to be fully characterized. We use a chemical transport model and its adjoint(More)
An Agent Based Model was developed to help analyze the importance of the size, number, operating time, and placement of resources dispensaries and processing centers in Phase II of a Humanitarian Aid/Disaster Relief (HA/DR) mission. The ABM developed takes into account population density, social economic attributes of the population, ethnicity makeup of the(More)
Filamentous plastic litter collected from two beaches in south west England has been characterized by FTIR and XRF. The majority of samples were constructed of polyethylene and consisted of twisted or braided strands of a variety of colours that appeared to be derived from commercial fishing nets. A number of different elements were detected among the(More)
Humanitarian Aid/Disaster Relief (HA/DR) missions are a continuing concern for world governments and NGOs. The vastness and complexity of the HA/DR missions emphasizes the need for quality conceptual model (CM) development (CMD). Two challenges of CMD are correctly determining the fidelity to model the system and validating the CM. CMD relies heavily on(More)
Parkinson's disease is a chronic neurodegenerative condition that manifests clinically with various movement disorders. These are often treated with the dopamine-replacement drug levodopa. However, the dosage of levodopa must be kept as low as possible in order to avoid the drug's side effects, such as the involuntary, and often violent, muscle spasms(More)
An Open-Source, extensible spacecraft simulation and modeling (Open-SESSAME) framework was developed with the aim of providing to researchers the ability to quickly test satellite algorithms while allowing them the ability to view and extend the underlying code. The software is distributed under the GPL (General Public License) and the package's(More)
Very little systematic information exists on the occurrence and concentrations of antimony (Sb) in consumer products. In this study, a Niton XL3t field-portable-X-ray fluorescence (FP-XRF) spectrometer was deployed in situ and in the laboratory to provide quantitative information on Sb dissipated in plastic items and fixtures (including rubber, textile and(More)