Rafael Masot

Achieving Maximum Efficiency in Three-Phase Systems With a Shunt Active Power Compensator Based on IEEE Std. 1459

IEEE Standard 1459-2000 establishes that in an efficient electrical system, only the fundamental positive-sequence active power must be present. This paper proposes a new set of reference currents based on the IEEE Standard 1459-2000 for the control of a three-branch four-wire shunt active power compensator. Reactive, unbalance, and harmonic distortion phenomena can be cancelled out upstream from the point of connection, achieving maximum efficiency of the three-phase four-wire electrical system. In addition, a new current control and a three-dimensional space vector pulsewidth-modulation technique are proposed to develop a shunt active power compensator. Simulation and experimental results demonstrate that the proposed shunt active power compensator improves the upstream electrical quality of the power network, achieving maximum efficiency according to IEEE Standard 1459-2000 specifications.

Quantification of organic acids using voltammetric tongues

Recently, electronic tongues (ET) have appeared as an excellent alternative to traditional techniques for the evaluation of food quality and processes. ET systems are based on arrays of low selectivity sensors that are simultaneously sensitive to several components in a measured sample (cross-sensitivity). The aim of this study was to determine the ability of an ET based on pulse voltammetry to quantify organic acids (ascorbic, citric and malic acids) in simple (SS) and binary solutions (BS) using different electrodes. The most significant electrodes for ascorbic acid prediction were Ni and Ag for SS, and Ag and Ir for BS where positive pulses were more suitable than negative ones. The prediction of citric and malic acids in SS and BS were suitable using Ir, Rh, Pt, Ag and Cu electrodes, using both positive and negative pulses.

Classification of unaltered and altered dry-cured ham by impedance spectroscopy: a preliminary study.

The aims of this work were characterized by the physicochemical and microbiological features of dried-cured hams classified by the manufacturer as altered (deep spoilage and swollen) and unaltered, as well as, correlated these results with the electronic measurements of impedance spectroscopy, in order to lay the groundwork to design a suitable electrode to be used for checking in line all dry-cured ham elaborated. Double electrode and coaxial needle electrode were used in a frequency range of 100Hz to 1MHz. The electronic measurements of the two electrodes were able undoubtedly to discriminate between altered and unaltered dry-cured hams; moreover a tendency to classify between deep spoilage and swollen hams was shown. The values into the range of frequencies between 100Hz-1000Hz, for both electrodes, showed the best clustering results. More studies are needed to select the best electrode which can be transformed in a robust and versatile electrode which could be used for checking in line all dry-cured ham elaborated.

Teaching Electronics to Aeronautical Engineering Students by Developing Projects

Teaching electronics to an aerospace engineer with a very limited number of credits has been a major challenge for us. This goal has been achieved through a teaching method based on real projects that are closely related to aerospace engineering. Throughout this paper, the process of teaching electronics through two subjects, one compulsory and one elective, is described. Subsequently, a description of the major projects that have been implemented in the last years is given. The academic results have been very satisfactory, and project development has proved a widely accepted method of teaching by students.

Assessing heat treatment of chicken breast cuts by impedance spectroscopy

The aim of this work was to develop a new system based on impedance spectroscopy to assess the heat treatment of previously cooked chicken meat by two experiments; in the first, samples were cooked at different temperatures (from 60 to 90 ℃) until core temperature of the meat reached the water bath temperature. In the second approach, temperature was 80 ℃ and the samples were cooked for different times (from 5 to 55 min). Impedance was measured once samples had cooled. The examined processing parameters were the maximum temperature reached in thermal centre of the samples, weight loss, moisture and the integral of the temperature profile during the cooking–cooling process. The correlation between the processing parameters and impedance was studied by partial least square regressions. The models were able to predict the studied parameters. Our results are essential for developing a new system to control the technological, sensory and safety aspects of cooked meat products on the whole meat processing line.

Embedded pattern recognition systems for liquids classification: A comparison study

A comparative study among a Fuzzy ARTMAP, a Multi-Layer Feed-Forward network (MLFF) and a Linear Discriminant Analysis (LDA) has been done in a liquids classification system in order to obtain the best implementation on a microcontroller based system. These algorithms are initially trained with a multi-electrode array on a Personal Computer (PC) using several samples of waters to obtain the optimum architecture of the networks. Once it is trained, the computed data are programmed into the microcontroller, which then gives the water classification directly for new unknown water samples. The multi-electrode has been developed using thick-film technology

Design and Implementation of an Electronic Nose System for the Determination of Fish Freshness

An electronic nose has been designed to evaluate fish freshness. The e‐nose consists of 15 commercial sensors, a home‐made data acquisition system and a PC application that communicates with the data acquisition system. The equipment has been conceived so that the sensors can be configured in non‐standard operation modes in order to improve the sensors discrimination capabilities.

Gold Nanostars Coated with Mesoporous Silica Are Effective and Nontoxic Photothermal Agents Capable of Gate Keeping and Laser-Induced Drug Release

Herein, a novel drug photorelease system based on gold nanostars (AuNSts), coated with a mesoporous silica shell and capped with paraffin as thermosensitive molecular gate, is reported. Direct measurements of the surface temperature of a single gold nanostar irradiated using a tightly focused laser beam are performed via a heat-sensitive biological matrix. The surface temperature of a AuNSt increases by hundreds of degrees (°C) even at low laser powers. AuNSts coated with a mesoporous silica shell using a surfactant-templated synthesis are used as chemotherapeutic nanocarriers. Synthetic parameters are optimized to avoid AuNSt reshaping, and thus to obtain nanoparticles with suitable and stable plasmonic properties for near-infrared (NIR) laser-triggered cargo delivery. The mesoporous silica-coated nanostars are loaded with doxorubicin (Dox) and coated with octadecyltrimethoxysilane and the paraffin heneicosane. The paraffin molecules formed a hydrophobic layer that blocks the pores, impeding the release of the cargo. This hybrid nanosystem exhibits a well-defined photodelivery profile using NIR radiation, even at low power density, whereas the nonirradiated sample shows a negligible payload release. Dox-loaded nanoparticles displayed no cytotoxicity toward HeLa cells, until they are irradiated with 808 nm laser, provoking paraffin melting and drug release. Hence, these novel, functional, and biocompatible nanoparticles display adequate plasmonic properties for NIR-triggered drug photorelease applications.

Design and Implementation of a Low‐Cost Non‐Destructive System for Measurements of Water and Salt Levels in Food Products Using Impedance Spectroscopy

The IQMA and the DTA have developed a low‐cost system to determinate the contents of water and salt in food products as cured ham or pork loin using non‐destructive methods. The system includes an electronic equipment that allows the implementation of impedance spectroscopy and an electrode. The electrode is a concentric needle which allows carrying out tests in a non‐destructive way. Preliminary results indicate that there is a correlation between the water and salt contents and the module and phase of the impedance of the food sample in the range of 1 Hz to 1 MHz.