Design of arbitrary optical filters in silicon-on-insulator using evanescently-coupled Bragg gratings

Spectral filters are experiencing an increasing demand in several applications of the silicon- on-insulator (SOI) platform. Many works have demonstrated that arbitrary frequency responses can be synthesized by apodizing the coupling coefficient profile of an integrated Bragg grating. However, the high index contrast of the SOI platform hinders their practical implementation, due to the difficulty of achieving the precise control required in the Bragg strength. In this paper, we propose the implementation of spectral filters using an architecture based on placing loading segments within the evanescent field region of a photonic wire waveguide. The Bragg coupling coefficient can be accurately controlled by simply moving the segments away from, or closer to, the waveguide core. The layerpeeling algorithm, in conjunction with a Floquet-Bloch modal analysis, allows to determine the spatial distribution of the segments that synthesizes the desired spectrum. The proposed topology is verified by designing a filter with five arbitrary passbands.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Automatic design of high-performance fiber-chip surface grating couplers based on Floquet-Bloch mode analysis

We propose a new strategy to automatically design highly efficient fiber-chip surface grating couplers. High performance designs are achieved with a substantially reduced computational cost by combining Floquet-Bloch mode analysis with a multi-objective optimization technique (genetic algorithms)

Impact of thermal sterilization on the physicochemical-sensory characteristics of Californian-style black olives and its assessment using an electronic tongue

The effect of thermal sterilization processes on the physicochemical parameters and sensory characteristics of Californian-style black olives, from Hojiblanca and Manzanilla Cacereña brine solutions, were evaluated. Two-way ANOVA showed that Hojiblanca olives had a lower phenols content and defect intensity and that increasing the sterilization period resulted in a decrease in total phenols and an increase of the cooked defect. The impact of thermal sterilization was further evaluated using a potentiometric electronic tongue, which was capable of discriminating the different sterilization treatments (repeated K-fold cross-validation sensitivity: 89.0?±?15.0% to 97.0?±?6.0%). Moreover, multiple regressions allowed the prediction of phenols (R2???0.95?±?0.03) and the intensity of the defect (R2???0.95?±?0.04). These results point out the feasibility of the electronic tongue as an analytical tool for monitoring the effects of thermal sterilization treatments. Furthermore, the satisfactory results obtained for the brine solutions may foresee a practical non-destructive method for indirect quality assessment of table olives.Consejería de Educación y Empleo of the Junta de Extremadura to work with a scholarship at the Polytechnic Institute of Bragança for 4 months (Resolución de 18 de julio de 2019, DOE de 25 de julio de 2019, no 143) (Expedient number A28). Nuno Rodrigues thanks to National funding by FCT- Foundation for Science and Technology, P.I., through the institutional scientific employment program-contract. The authors are also grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER, under Programme PT2020, for the financial support of CIMO (UID/AGR/00690/2019) and of CEB (UID/BIO/04469/2019) and to BioTecNorte operation (NORTE-01-0145-FEDER-000004)info:eu-repo/semantics/publishedVersio

MPC for Tracking Periodic References

In this paper a new model predictive controller for tracking arbitrary periodic references is presented. The proposed controller is based on a single layer that unites dynamic trajectory planning and control. A design procedure to guarantee that the closed loop system converges asymptotically to the optimal admissible periodic trajectory while guaranteeing constraint satisfaction is provided. In addition, the constraints of the optimization problem solved by the controller do not depend on the reference, allowing for sudden changes in the reference without loosing feasibility. The properties of the proposed controller are demonstrated with a simulation example of a ball and plate system.MINECO-Spain and FEDER under project DPI2013-48243-C2-2-RUniversity of Seville under contracts 2014/425 and 2014/758European Research Council under the European Unions Seventh Framework Programme (FP/2007- 2013)/ ERC Grant Agreement n. 30760

MPC for tracking periodic reference signals

This paper is devoted to the design of a predictive controller for constrained linear systems to track periodic references. The only assumption on the dynamics of the reference is that it is periodic and its period is known. It is also assumed that the reference signal is a priori known by the controller. Inspired in the hierarchical control scheme based on the trajectory planification, the ideas of the MPC for tracking [Limon et al., 2008] are extended to this case. The proposed predictive controller has the future sequence of inputs and an artificial reference as decision variables. The cost function is divided into two terms: one penalizes the tracking error with the artificial reference and other penalizes the deviation of the artificial reference to the reference to be tracked. Stability is ensured thanks to the addition of two constraints: a terminal constraint on the predicted trajectory and a constraint that enforces the artificial reference to be periodic. It is proved that the proposed controller is recursively feasible and the controlled system satisfies the hard constraints, is asymptotically stable and converges to the best possible reachable trajectory. The properties of the proposed controller are illustrated in an example.Spanish Ministry of Science and Innovation and FEDER DPI2008-05818Spanish Ministry of Science and Innovation and FEDER DPI2010-21589-C05-0

Electrochemical nanostructured biosensors for determination of ultra-trace anabolic drugs in bovine samples

Los anabólicos son drogas capaces de incrementar la retención de nitrógeno aumentando la acumulación de proteínas en los animales, son utilizados en producción agropecuaria y entrañan un serio problema para la salud pública (FAO/OMS, Roma, 1975). Entre estos compuestos se encuentran los β-agonistas, los cuales empleados en dosis bajas presentan usos terapéuticos, mientras que utilizados en altas dosis muestran su función anabolizante, generan residuos cuya acumulación representa un peligro para los consumidores. Debido al reporte de serias intoxicaciones, fue prohibida su utilización como promotores del crecimiento. El análisis de dichos residuos en muestras de origen animal requiere elevada sensibilidad y selectividad. Las metodologías usadas para su determinación son la cromatografía líquida y gaseosa con detección por espectroscopia de masas y técnicas inmunológicas como ELISA y RIA. Alternativamente, y debido a que los β-agonistas y otros anabólicos como el zeranol contienen grupos electroactivos, la detección electroquímica representa una estrategia para ser considerada. Esta detección combinada con el uso de electrodos de láminas impresas ofrece ventajas como sencillez, versatilidad, bajo precio, mínimo volumen de muestra requerido y portatibilidad del sistema, lo que permite realizar ensayos in situ. La incorporación de nanomateriales (nanopartículas metálicas, nanotubos de carbono, etc.) en la superficie de dichos electrodos posibilita mejorar la sensibilidad en comparación con los métodos tradicionales. Dichos materiales se emplean en la construcción de sensores, pues ofrecen un aumento en el área superficial, conductividad y propiedades electrocatalíticas, así como también una excelente biocompatibilidad por lo que pueden utilizarse como soportes para la inmovilización de biomoléculas en reacciones inmunológicas y/o enzimáticas.Anabolic, drugs able to increase nitrogen retention by increasing the accumulation of proteins in animals have been used in livestock production and involve a serious problem for public health (FAO/OMS, Rome 1975). Within these compounds include β-agonists, which have therapeutic uses, but to express its anabolic function require high doses, which generate waste whose accumulation represents a danger for consumers. Since the report of serious food poisoning their use as growth promoter was banned. The analysis of such residues in animal samples should be performed with high sensitivity and selectivity. The most widely used methods are techniques of liquid chromatography and gas chromatography with mass spectroscopy detection, but can also be used immunological techniques such as ELISA and RIA. Alternatively, and because the β-agonists containing electroactive groups, electrochemical detection should be considered. This detection combined with the use of screen printed carbon electrodes provides many advantages such as simplicity, versatility, low price, minimum sample volume required and portability system, which allows “in situ’’ determinations. Another strategy to improve sensitivity over traditional methods is the incorporation of nanomaterials (metal nanoparticles, carbon nanotubes, etc.). These materials represent a tool for sensors construction because they provide an increased surface area, high conductivity, electrocatalytic properties, as well as an excellent biocompatibility; therefore can be used as supports for biomolecule immobilization on immunological and/or enzymatic reactions.Fil: Regiart, Daniel Matias Gaston. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; ArgentinaFil: Pereira, Sirley Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; ArgentinaFil: Messina, Germán Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; ArgentinaFil: Fernández Baldo, Martín Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; ArgentinaFil: Spotorno, Viviana G.. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; ArgentinaFil: Bertolino, Franco Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; ArgentinaFil: Raba, Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; Argentin

Assessing acrylamide content in sterilized Californian-style black table olives using HPLC-MS-QQQ and a potentiometric electronic tongue

The study aimed to evaluate the effects of olive cultivar (cvs. Manzanilla Cacereña and Hojiblanca) and the sterilization intensity/time-period (F0 of 1025minat 121±3°C) on the formation of acrylamide in table olives and brine. Olive cultivar and thermal sterilization had a significant impact on the amount of acrylamide produced (varying from 228±94 to 286±110 and 336±126 to 373±159ngg1, for table olives and brine, respectively, determined by HPLC-MS-QQQ). Moreover, for both cultivars, linear positive relationships (0.931R20.994) were found between the acrylamide concentration in olives and respective brine solutions, allowing to foresee a non-destructive indirect methodology for quantifying acrylamide in table olives. Finally, a potentiometric E-tongue was used to quantify acrylamide in both matrices. The lipid sensor membranes comprised on the sensor device showed potentiometric semi-logarithmic responses (0.962R20.999) towards the acrylamide concentration for aqueous standard solutions, permitting the establishment of accurate multiple linear predictive models for the quantification of acrylamide in olives and brine solutions (repeated K-fold-CV: 0.97±0.03R20.99±0.01; 12±8RMSE 28±14ngg1) for both olive cultivars. E-tongue could be used as non-destructive indirect detection method of acrylamide, based on the brine solution evaluation, and so, a complementary analytical tool to the conventional chromatographic analysis.Daniel Martín-Vertedor thanks the mobility grant of the Consejeríade Educación y Empleo of the Junta de Extremadura to work with ascholarship at the Polytechnic Institute of Bragança for 4 months(Resolución de 18 de julio de 2019, DOE de 25 de julio de 2019, no143) (Expedient number A28). The authors are grateful to theFoundation for Science and Technology (FCT, Portugal) and FEDERunder Program PT2020 forfinancial support to CIMO (UIDB/00690/2020) and to CEB (UIDB/04469/2020) units and to BioTecNorte op-eration (NORTE-01-0145-FEDER-000004) funded by the EuropeanRegional Development Fund under the scope of Norte2020 - ProgramaOperacional Regional do Norte. Nuno Rodrigues thanks to Nationalfunding by FCT- Foundation for Science and Technology, P.I., throughthe institutional scientific employment program-contract. The authorswish to thank to the Elemental and Molecular Analysis Service be-longing to the Research Support Service of the University ofExtremadura by the development of acrylamide determination methodand MaDolores López Soto and Elena Rodríguez Paniagua for their helpin the performance of this study.info:eu-repo/semantics/publishedVersio

Screen-printed electrode based electrochemical detector coupled with ionic liquid dispersive liquid–liquid microextraction and microvolume back-extraction for determination of mercury in water samples

A novel approach is presented, whereby gold nanostructured screen-printed carbon electrodes (SPCnAuEs) are combined with in-situ ionic liquid formation dispersive liquid–liquid microextraction (in-situ IL-DLLME) and microvolume back-extraction for the determination of mercury in water samples. In-situ IL-DLLME is based on a simple metathesis reaction between a water-miscible IL and a salt to form a water-immiscible IL into sample solution. Mercury complex with ammonium pyrrolidinedithiocarbamate is extracted from sample solution into the water-immiscible IL formed in-situ. Then, an ultrasound-assisted procedure is employed to back-extract the mercury into 10 µL of a 4 M HCl aqueous solution, which is finally analyzed using SPCnAuEs. Sample preparation methodology was optimized using a multivariate optimization strategy. Under optimized conditions, a linear range between 0.5 and 10 µg L−1 was obtained with a correlation coefficient of 0.997 for six calibration points. The limit of detection obtained was 0.2 µg L−1, which is lower than the threshold value established by the Environmental Protection Agency and European Union (i.e., 2 µg L−1 and 1 µg L−1, respectively). The repeatability of the proposed method was evaluated at two different spiking levels (3 and 10 µg L−1) and a coefficient of variation of 13% was obtained in both cases. The performance of the proposed methodology was evaluated in real-world water samples including tap water, bottled water, river water and industrial wastewater. Relative recoveries between 95% and 108% were obtained.The authors would like to thank the Spanish Ministry of Science and Innovation (Project nos. CTQ2011-23968 and CTQ2011-24560), the Generalitat Valenciana (Spain) (Project nos. ACOMP/2013/072, PROMETEO/2013/038 and GV/2014/096) and the University of Alicante (Spain) (Project no. GRE12-45) for the financial support. E. Fernández and D. Martín-Yerga also thank Generalitat Valenciana and Ministry of Economy and Competitiveness, respectively, for their fellowships

Enhanced sensitivity subwavelength grating waveguides for silicon photonics sensing applications

OSA (Optical Society of America)In this work we will review the enormous potential of subwavelength grating waveguides for sensing applications in the near and mid-infrared bands, demonstrating the capability to engineer the mode profile to maximize the light-matter interaction.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Vigilancia ambiental de la calidad del aire realizada, en el distrito Pariñas, provincia Talara, departamento Piura en julio de 2019

Evalúa el comportamiento y la calidad ambiental del aire en el área de influencia de las operaciones de la Refinería de Talara, en el distrito de Pariñas, provincia de Talara, departamento de Piura en julio de 2019. Menciona como una de sus conclusiones que las concentraciones horarias y promedios móviles de 8 horas de monóxido de carbono (CO) registradas en la estación de vigilancia ambiental de la calidad del aire CA-TA-01 del 1 al 10 de julio de 2019, no excedieron los ECA para aire, aprobado mediante Decreto Supremo N.° 003-2017-MINAM