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In this paper, a robust control algorithm, based on sliding modes techniques, designed for trajectory tracking is applied to a fixed-wing small Autonomous Aerial Vehicle (AAV). Based on a mathematical modeling, parameters identification, and aerodynamics of both the AAV fuselage and its mobile surfaces a full dynamical model is obtained, where the control is proven. However, for control design, simplified versions of the motion models are studied resulting in simplified independent controller for the roll, pitch and yaw trajectories. Due to the nature of such controller, time derivative of control variables are needed but not available. Numerical differentiators also based on sliding modes are used in order to estimate those derivatives. Simulation results are given to illustrate the performance of the proposed tracking controller under parametric and unmodeled dynamics.Copyright © 2011 by ASME

The risk analysis of an oil complex require a careful estimation of failure consequences and, as an important component, the indirect loss may play a relevant role, especially for high production facilities. In this work, the interaction between the industrials sectors is considered uncertain by modeling it through random variables. The contribution of the five most important sectors is considered to be normally distributed and the value of its loss, as reported by INEGI (1986), is considered to be the mean value and a coefficient of variation of 0.1 is assumed for each sector loss. By using Monte Carlo techniques, the loss for each of the five sectors is simulated and the total indirect loss is calculated. The production loss is obtained by assuming that time to restore the production rate in the five platforms is 33 months. For each trial, the I/O matrix is obtained, the vector of predisaster products is calculated and the production loss is estimated. Then, the demand and the production level post-disaster are assessed. Finally, the second round and total losses are estimated. With the sample of indirect losses obtained, its probability distribution is estimated. The probabilistic description of the indirect loss includes, among other epistemic uncertainties, the one related to the sector interactions, which are considered as linear in a simplified way.Copyright © 2005 by ASME

Indirect losses result from the economical disruption after a catastrophic event destroys most of the production facilities of a certain industry, as a consequence other economic sectors may be affected. The magnitude of these losses depends on importance of the economic links between the sectors and on the elapsed time before all the economical activities of all sectors are restarted. The model is adapted after the Leontief Input-Output representation and actual figures of the Mexican economy are used to estimate the level of the economical disruption that would occur by assuming that a hurricane provokes the collapse of an oil complex in Mexico. This calculation may be used to generate redundancy measures capable to mitigate the risk exposure of the national economy regarding the potential occurrence of powerful hurricanes on the offshore oil production area of Mexico.Copyright © 2004 by ASME

The measurement of ultra-weak magnetic fields with nanometer-scale spatial resolution is a powerful tool for investigating several biological, chemical and physical systems. Among the available detectors, SQUIDs are the most sensitive magnetic field and flux detectors and are rapidly approaching the quantum sensitivity limit. To reach such sensing capability, technological advances in the fabrication of nanoscale SQUIDs with submicrometric loops are needed. In this work we present a novel process for the fabrication of nanoscale SQUIDs, based on superconducting vertical Nb nanoconstrictions. The fabrication process uses laser lithogra- phy to define the device geometry, focused ion beam to mill the top surface of the Nb in a nanometer-sized region across the width of the film and anodization to define the final thickness of the nanoconstriction and at the same time to embed the ion- implanted amorphous layer produced by the FIB milling step. A preliminary electrical characterization of nano-sized single Josephson junctions and SQUIDs fabricated with this process is also reported.