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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 most widely used substrates for fluorescent immunoassay are based on transparent materials such as glass or plastic with almost no optical functionality. Very recently, optical nanostructures made of metal on dielectrics have been proposed to perform photon management features mediated by surface or localized plasmons. In particular, resonant ring-shaped antennas have been demonstrated to enhance the amount of overall fluorescence radiated from few emitters and provide some control on the emission direction [1]. However, such an approach based on plasmonic structures is limited by the material absorption, especially in the visible region of the spectrum. As an alternative strategy, photonic crystals have been used [2]. In that case, it is possible to resonantly couple a laser radiation to specific leaky modes (e.g. in the Kretschmann configuration or via grating coupling) in such a way that an increase of fluorescence excitation is produced because of a near-field enhancement. In this contribution, we propose an hybrid approach for simply improving the fluorescence radiation that can be excited and extracted on a glass-based substrate for immunoassay sensing. We take inspiration from plasmonics and photonic crystals and propose the use of surface modes sustained on planar multilayers made of different dielectric materials. Although the multilayer is an example of one-dimensional photonic crystals (1DPC), the modes involved in the enhancement mechanism are very similar to surface plasmons, with some additional advantages such as: (i) the possibility of having either TE or TM polarized modes, (ii) a higher Q factor, (iii) a higher near-field intensity on the 1DPC surface. These modes, called Bloch Surface Waves (BSW) can also act as “drain” channels for the radiation emitted by organic dyes placed on the 1DPC surface [3]. This phenomenon, recalling the well-known Surface Plasmon Coupled Emission (SPCE) is gaining popularity in the biosensing field [4]. As a practical application of this mechanism, ring-shaped gratings are fabricated on the 1DPC (FIB and PECVD processes) in such a way that they can be used for coupling an external radiation to focused BSW and to diffract the BSW-coupled emission normally to the 1DPC surface. When specific receptors (marked antibodies), after surface chemical functionalization, are spotted on different ring antennas arranged as an array, a noticeable enhanced fluorescence is detected by using a simple wide-field fluorescence imaging system, like in conventional immunoassays for target (antigens) detection. We will show the robustness of this approach, requiring almost no alignment of the laser source and very low numerical aperture for collection. REFERENCES [1] H. Aouani et al., Nano Letters 11, 637-644 (2011). [2] N. Ganesh et al, Nature Nanotechnology 2, 515-520 (2007). [3] M. Ballarini et al., Appl. Phys. Lett. 99, 043302-043305 (2011). [4] R. Badugu et al., Anal. Biochem. 442, 83-96 (2013). [5] A. Angelini et al., N. J. Phys., 15, 073002 (2013).

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.

Recently it has been proven that the magnetic response of magnetic nano-objects such as nanoparticles, nanobeads, and small cluster of molecules can be effectively measured by using a Superconducting Quantum Interference Device (SQUID) with a small sensitive area. Here, we present a high sensitivity nanoSQUID based on deep submicrometer Josephson tunnel junctions fabricated by a Focused Ion Beam (FIB) sculpting method. The nanosensor consists of a niobium superconducting loop (0.4 × 1.0 ?m^2) interrupted by two sandwich nanojunctions (Nb/Al-AlOx/Nb) having an area of about (300 × 300) nm^2. An experimental investigation of the main characteristics of such nanodevice as a function of the temperature is presented.

In this paper, an experimental investigation of the main characteristics of a niobium nano Superconducting QUantum Interference Device (nanoSQUID) as a function of the temperature (9-0.3 K) is presented. The nanosensor consists of a niobium superconducting loop (0.4 × 1.0μm2) interrupted by two sandwich nanojunctions (Nb/Al-AlOx/Nb) having an area of about (300 × 300) nm2. These nanodevices have been fabricated by means of a focused ion beam sculpting method, which is used as a lithographic technique to define the various elements of the SQUID. We have performed measurements of current-voltage, critical current-magnetic flux characteristics, and switching current distributions from the zero voltage state for different temperatures. The high critical current modulation depths and the low intrinsic dissipation exhibited by these devices ensure a suitable sensitivity for nanoscale applications in the whole temperature range investigated.

Nanosized PTFE-based core-shell particles can be prepared by emulsifier-free seed emulsion polymerization technique starting from spherical or rod-like PTFE seeds of different size. The shell can be constituted by the relatively high Tg polystyrene and polymethylmethacrylate as well as by low Tg polyacrylic copolymers. Peculiar thermal behavior of the PTFE component is observed due to the high degree of PTFE compartmentalization. A very precise control over the particle size can be exerted by properly adjusting the ratio between the monomers and the PTFE seed. Samples with uniformity ratios suited to build 2D and 3D colloidal crystals are easily prepared. 2D colloidal crystal of spheres leads to very small 2D nanostructuration, useful for the preparation of masks with a combination of nanosphere lithography and reactive ion etching. 3D colloidal crystals were also obtained featuring excellent opal quality.