Modeling and Control of mini UAV

International audienc

Minimization of measuring points for the electric field exposure map generation in indoor environments by means of Kriging interpolation and selective sampling

In a world with increasing systems accessing to radio spectrum, the concern for exposure to electromagnetic fields is growing and therefore it is necessary to check limits in those areas where electromagnetic sources are working. Therefore, radio and exposure maps are continuously being generated, mainly in outdoor areas, by using many interpolation techniques. In this work, Surfer software and Kriging interpolation have been used for the first time to generate an indoor exposure map. A regular measuring mesh has been generated. Elimination of Less Significant Points (ELSP) and Geometrical Elimination of Neighbors (GEN) strategies to reduce the measuring points have been presented and evaluated. Both strategies have been compared to the map generated with all the measurements by calculating the root mean square and mean absolute errors. Results indicate that ELSP method can reduce up to 70% of the mesh measuring points while producing similar exposure maps to the one generated with all the measuring points. GEN, however, produces distorted maps and much higher error indicators even for 50% of eliminated measuring points. As a conclusion, a procedure for reducing the measuring points to generate radio and exposure maps is proposed based on the ELSP method and the Kriging interpolation.This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors

A novel technique for sterilization using a power self-regulated single-mode microwave cavity

In this paper, a novel technique to achieve precise temperatures in food sterilization has been proposed. An accurate temperature profile is needed in order to reach a commitment between the total removal of pathogens inside the product and the preservation of nutritional and organoleptic characteristics. The minimal variation of the target temperature in the sample by means of a monitoring and control software platform, allowing temperature stabilization over 100 °C, is the main goal of this work. A cylindrical microwave oven, under pressure conditions and continuous control of the microwave supply power as function of the final temperature inside the sample, has been designed and developed with conditions of single-mode resonance. The uniform heating in the product is achieved by means of sample movement and the self-regulated power control using the measured temperature. Finally, for testing the sterilization of food with this technology, specific biological validation based on Bacillus cereus as a biosensor of heat inactivation has been incorporated as a distribution along the sample in the experimental process to measure the colony-forming units (CFUs) for different food samples (laboratory medium, soup, or fish-based animal by-products). The obtained results allow the validation of this new technology for food sterilization with precise control of the microwave system to ensure the uniform elimination of pathogens using high temperatures.This work was supported by the Ministerio de Economía y Competitividad under the project with reference DPI2014-61857-EXP

Benefits of using conductive plastics in shielding configurations to reduce radiated electromagnetic interference

Conductive plastic cabinets have become an alternative to traditional metallic enclosures to shield electronic equipment from electromagnetic interference. These materials allow a wide range of conductivities that can satisfy any particular design. In this paper the benefits of using conductive plastics in enclosure configurations have been evaluated. A design with an outer metallic layer and an inner layer of conductive dielectric can provide advantages from both materials since a conductive plastic box is lighter and its shielding properties may have advantages over metallic materials. An optimum for resonance suppression has been obtained for the hybrid structure. These shielding structures have been evaluated with the help of measurements and simulations. Shielding effectiveness and Q-factor have been used to compare the capabilities of these enclosures with the metallic ones showing their benefits and possibilities. Resonance suppression and shielding levels provided by conductive plastics are discussed.This work was funded by Fundación Séneca, Agencia Regional de Ciencia y Tecnología, through the project 00700/PPC/04 and partly done during a research stay funded by the “Programa de formación y movilidad del personal docente e investigador de la Universidad Politécnica de Cartagena (PMPDI-UPCT-2007)” at the Physical Layer Group, Department of Electronics, University of York

A novel design of a robust ten-port microwave reflectometer with autonomous calibration by using neural networks

In this study, a novel ten-port waveguide microwave sensor is designed, implemented, calibrated and tested in order to obtain the reflection coefficient magnitude and phase. This reflectometer is based on the well known six-port structure but the number of detectors has been increased to eight in order to improve the sampling procedure of the standing wave present within the waveguide. In addition, a learning method based on neural networks’ usage has been implemented for autonomous calibration from the data collected by a vector network analyzer. An automated procedure consisting of a moving sample within a multimode cavity has enabled different reflection coefficients to be obtained. Neural networks have been employed in order to learn the relationship between the actual reflection parameter and the acquired signals from eight power detectors. This novel device has been calibrated with a neural architecture based on radial basis functions and the error of device measurements has been analyzed. This new design and the incorporated neural network calibration allow one to avoid problems caused by fault or nonlinearity of the detectors, and to get robustness, flexibility and adaptability characteristics for the presented device

Noble gas variation during partial crustal melting and magma ascent processes

Noble gas isotopes, although present in trace amounts, are generally more reliable and less ambiguous recorders of their source than the major volatile species. In volcanic settings in particular, this advantage derives from their chemical inertness, as noble gas isotopic and elemental fractionations are strongly coupled to their source and modified only by physical processes during magma ascent and eruption. The Neogene volcano El Hoyazo (Betic Cordillera, SE Spain) is a highly favourable natural laboratory to study the links between partial crustal melting processes occurring at depth and the eruptive products at the surface, because partially melted crustal xenoliths are preserved in silicic lavas. Comparing the noble gas isotopic compositions of xenoliths and lavas has the potential to yield new insights into volatile behaviour during melting processes at inaccessible depths in the crust. At El Hoyazo, noble gases trapped in lava glasses, and the fluid/melt inclusions within xeno- and phenocrysts, provide novel information on: (i) their response to the crustal melting process including mechanisms such as magma mixing (and crustal assimilation) of two endmembers: i.e. the extracted felsic melt from the country metapelitic crust, and the basic-intermediate magma from the underplating in the region. The results reveal significant modification of magmatic noble gases by the interaction with the partially melted crust; (ii) noble gas variations during degassing and magma ascent, showing higher atmospheric influence in the lava samples from shallower depths than in the deeper lavas and minerals; and (iii) higher magmatic influence in crystals of garnet from deeper lava than in both shallower crystals of amphibole, and garnet crystals within the crustal xenoliths. In addition, we find that noble gases in melt inclusions are also likely accumulating in their shrinkage bubbles, and not only remaining dissolved in the melt.Postprint3,51

Fast computation of shielding effectiveness of metallic enclosures with apertures and inner elements

In this study, radiated immunity and emission of a metallic box with apertures have been evaluated through a fast approach. The influence of printed circuit boards inside the enclosure has been studied and also the effect of placing conductive polymer sheets in the housing in order to characterize the behaviour of these materials used nowadays for shielding cabinets. Measurements have been carried out in anechoic chamber in order to evaluate the approximated technique showing its limitations and advantages. Since good agreement has been found between simulations and measurements, this approach can be used for design or optimization purposes with the main advantage of reduced time calculations.This work has been funded by Fundación Séneca, Agencia Regional de Ciencia y Tecnología through the project 00700/PPC/04

Improved control on the microwave devulcanizing of ground tire rubber by means of sulphur gas sensors

The success of a Ground Tire Rubber (GTR) devulcanization process relies on the elimination of the Sulphur atoms that are crosslinking the rubber polymer. From the Chemical point of view, this requires providing enough energy to break the Sulphur bonds while preserving the Carbon bonds, to ensure a high quality devulcanized GTR for being of interest to the rubber manufacturing industry. GTR is very responsive to microwaves due to the presence of Carbon Black (CB) in its composition, so the radiant energy is absorbed quickly in the form of thermal energy. When its temperature reaches 140°C, the breakage of Sulphur bonds may happen under an exothermic reaction, but also some new links might be built under that condition. Therefore, from the Physical point of view, the released Sulphur in the gaseous form of SO2, H2S, and/or CS2 must be promoted to abandon the reactor to avoid its recombination. In this work, microwave devulcanization is monitored by detecting the concentration of Sulphurous gases at the exhaust of the reactor. These sensors are very effective especially when pyrometer readings are degraded because of the gaseous layer on the GTR during the process.This research project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement number 870000. More information at https://valuerubber.eu/. The authors acknowledge CETEC and Synthelast for the GTR powder. Authors would like to extend the gratitude to Mr. Juan Antonio Albaladejo-López for his help with the mechanical development of the set u

Assesment of coaxial filters for the instalation of metallic mode stirrers or turntables in multimode microwave ovens

In this contribution authors show the usage of several coaxial filters that avoid microwave leakage when using metallic mode stirrers within microwave multimode cavities. We describe the simulation schemes and characteristics for the different coaxial filters employed when introducing the metal axis of the mode-stirrer in the applicator. Additionally, the measurement setup that allows to validate the filtering capabilities is also described in detail. Figure 1 shows the cross-section scheme of a typical multimode microwave cavity. A waveguide feeding port is used to introduce the microwave energy in the cavity. The movement of the mode stirrer causes different electric field distribution patterns within the cavity and the material which may result in the reduction of cold and hot spots. Metallic materials are preferred versus dielectric ones to manufacture stirrers because metals are more effective than dielectrics to reflect and stir the microwave energy. However, when the metallic axis of the mode stirrer goes through the cavity walls a coaxial line is generated and the microwave electric field may leak through the coaxial port very easily. Several coaxial filtering structures are evaluated and validated to prevent electric field scaping from the applicator

Tutoría grupal para la resolución de problemas de síntesis de amplificadores sintonizados y análisis de mezcladores en ingeniería de telecomunicación

[SPA]En esta comunicación se explica la metodología de trabajo seguida en la ETSI de Telecomunicación de la Universidad Politécnica de Cartagena para el desarrollo de competencias de trabajo en grupo a través de la realización de tutorías grupales. Los alumnos elegidos para llevar a cabo estas actividades son los matriculados en la asiguatura optativa de Subsistemas de Radiofrecuencia, perteneciente a cuarto curso de la titulación de Ingeniero de Telecomunicación. La tuturía grupal se ha centrado en la resolución de problemas tipo de diseño de amplificadores sintonizados de radiofrecuencia así como el análisis de mezcladores. La propia evaluación del proceso por parte de los alumnos y los profesores muestran que los alumnos se sienten satisfechos en este tipo de actividades debido a la agilidad en la identificación de dudas y su resolución. Sin embargo, en los casos de alumnos sobresalientes el proceso puede ser un poco frustrante debido a su alto dominio previo de la asignatura. [ENG]In this communication, the methodology followed by teachers and students of the ETSI de Telecomunicación within Universidad Politécnica de Cartagena for the development of group cooperation competencies by means of group tutorials is explained. The chosen students for carrying out this activities belong to Radiofrequency Subsystems subject within the fourth academic year of Telecommunication Engineer Degree. Group Tutorial sessions have focused on 1474 typical RF tuned amplifiers design and mixer analysis problems. Students and teachers evaluation of the process shows that students are satisfied withi this kind of activities since doubts were quickly identified and solved. However, for outstanding students the process can be a bit frustrating due to their higher previous command of the subject.Campus Mare Nostrum, Universidad Politécnica de Cartagena, Universidad de Murcia, Región de Murci