Paulo C. Lozano

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The feasibility of electrostatically extracting and accelerating ions from room temperature ionic liquids in a high vacuum environment is investigated using externally wetted emitters similar to those manufactured for liquid metal ion sources, made out of tungsten wire and electrochemically treated to produce a sharp tip and to increase surface wettability.(More)
The problem of electrochemical decomposition due to extraction of single polarity ions from a novel ionic liquid ion source (ILIS) is solved by periodically alternating the voltage source so that the potential difference that appears across the double layer formed between the emitter conductive material and the liquid is maintained below the electrochemical(More)
Most existing GP regression algorithms assume a single generative model, leading to poor performance when data are nonstationary, i.e. generated from multiple switching processes. Existing methods for GP regression over non-stationary data include clustering and changepoint detection algorithms. However, these methods require significant computation, do not(More)
As aerospace systems become increasingly complex and the roles of human operators and autonomous software continue to evolve, traditional safety-related analytical methods are becoming inadequate. Traditional hazard analysis tools are based on an accident causality model that does not capture many of the complex behaviors found in modern engineered systems.(More)
Bayesian inference provides a probabilistic framework for combining prior knowledge with mathematical models and observational data. Characterizing a Bayesian posterior probability distribution can be a computationally challenging undertaking, however, particularly when evaluations of the posterior density are expensive and when the posterior has complex(More)
Electrosprays are devices in which nanometer sized droplets and/or solvated ions are electrically extracted from a liquid surface and accelerated to high velocities. They are usually constructed from conductive capillaries with one of the ends tapered down to a sharp tip with the purpose of enhancing the local electric field that produces the instability(More)
We have developed a mission concept that uses 3-unit cubesats to perform new measurements of lunar magnetic fields, less than 100 meters above the Moon’s surface. The mission calls for sending the cubesats on impact trajectories to strongly magnetic regions on the surface, and transmitting measurements in real-time to a nearby spacecraft, or directly to the(More)
Computational models of complex phenomena are an important resource for scientists and engineers. However, many state-of-the-art simulations of physical systems are computationally expensive to evaluate and are black box—meaning that they can be run, but their internal workings cannot be inspected or changed. Directly applying uncertainty quantification(More)
Millions of deaths worldwide are attributed annually to exposure degraded surface air quality and UVinduced skin cancer. However, the focus has been on surface emissions, and the contribution of high altitude emissions to these issues is rarely examined. In this thesis, potential links are investigated between high altitude emissions and damages or benefits(More)
Over-subscription, that is, being assigned too many tasks or requirements that are too demanding, is commonly encountered in temporal planning problems. As human beings, we often want to do more than we can, ask for things that may not be available, while underestimating how long it takes to perform each task. It is often difficult for us to detect the(More)