A compact model of the ZARC for circuit simulators in the frequency and time domains

Equivalent-circuit models containing fractional-order elements are often employed to make use of fractionalorder calculus in the frequency and time domains in a variety of applications. Many of these circuits contain constant-phase elements that appear in parallel with a resistor in a configuration called ZARC. But to avoid fractional order derivatives and include it in circuit simulators, the ZARC itself can also be replaced by equivalent circuit models that only contain integer order elements, such as resistors and capacitors. In this article, a novel compact model is presented to substitute the ZARC by a multiple-RC network. This model is valid for a continuous value of the order exponent and is applicable over a very wide range of frequencies, making it useful in both the frequency and time domains. Since it uses only basic functions and operators, it has been easily implemented as a subcircuit in circuit simulators. The validity of the model has been verified and it has been compared with some previously proposed passive circuit models. The model has also been discussed in relation to the initialization problem, which is an often overlooked challenge in fractional-order circuits.Universidad de Granada/CBU

Prevalencia de artritis séptica neonatal en un hospital universitario

Introducción: La artritis séptica neonatal es un padecimiento poco común que se ha relacionado con recién nacidos internados en la unidad de cuidados intensivos neonatal, cuyo principal factor de riesgo es el uso previo de catéter central. Objetivo: establecer la prevalencia de la artritis séptica neonatal en nuestro Hospital. Material y método: estudio observacional descriptivo de prevalencia. Se incluyeron todos los recién nacidos con diagnostico de artritis séptica neonatal internados un la unidad de cuidados intermedios e intensivos neonatal del Hospital Universitario Dr. José Eleuterio González del año 2003 al 2007. Se revisaron los expedientes y se registraron variables generales, factores de riesgo, bacteriología y mortalidad. Resultados: Se diagnosticaron 26 casos de artritis séptica neonatal durante el periodo de tiempo estudiado, solo 20 casos lograron criterios de inclusión: la prevalencia fue de 1.2 casos por cada 1,000 nacidos. La edad gestacional fue 39.2 ± 1.3 semanas, con peso 3193 ± 709 g. El factor de riesgo que se presento con mas frecuencia fue el antecedente de uso previo de catéter en 75% de los casos. Se aisló microorganismo en 80% de los casos, los bacterias grampositivas se aislaron en 80% de los casos; el Staphylococcus aureus fue el microorganismo aislado predominantemente en 75% de los casos. La presentación poliarticular fue en 40% de los casos. La mortalidad fue de 0%. Conclusiones: La prevalencia fue menor a lo reportado en la literatura. Los microorganismos grampositivos continúan siendo los microorganismos predominantes en la artritis séptica neonatal. La mortalidad es baja

Do one‐step mechanisms always involve simultaneous evolution of electron density? QTAIM/IQA analysis of the Curtius rearrangement

The Curtius rearrangement reaction is studied by using quantum theory of atoms in molecules (QTAIM) analysis of the electron density and the interacting quantum atoms (IQA) formalism. Although the rearrangements take place in one stage, two phases are distinguished when the rearranged atom is H: the first one corresponds to the separation of N2, and the second one to the N‐H/C‐H bond rearrangement. The transition state (TS) for the reaction does not represent an intermediate between reagent and product for the migration but for the isolation of the N2 molecule. When the migration is undergone by a fluorine atom, no electronic phases can be distinguished and the process is really concerted. As the migration happens closer to the TS, the TS is more similar to the product. The IQA analysis reveals different electron density evolutions for H and F migrations, and the scarce relevance (in terms of energy) of the point where BCPs appear or disappear.Xunta de Galicia | Ref. ED431C 2019/2

Drivers and Impact of ICT adoptation in the European Transport and Logistic Services

The availability of high quality transport and logistics services (TLS) is of paramount importance for growth and competitiveness of the European economy. The objective of this paper is to describe, from the continuous innovation perspective, how companies in this industry use ICT for conducting business and to assess the impact of this development for firms and for the industry as a whole. Using the SCP model and the bi-directional relationships of its elements the paper identifies the links between ICT adoption and innovation dynamics. Moreover, the analysis allows identifying the driving forces of ICT and its impact on selected business dimensions. On the driver’s side, there are three points that are worth mentioning: increasing market competition, the relationships of firms interacting with each other and the availability and quality of complementary assets such as employee skills and IT know-how. On the impacts’ side, firms advanced in terms of ICT usage are more likely to have outsourced business activities. Finally, a set of recommendations on how to further improve the continuous innovation factors in the TLS industry is presented

In-fiber Mach-Zehnder interferometer inscribed with femtosecond laser for high temperature sensing

In this work, an In-fiber Mach-Zehnder Interferometer has been manufactured within a standard optical fiber using direct inscription with a femtosecond laser. Different geometries have been tested in order to enhance the sensitivity of manufactured devices to high temperature sensing, reducing the total device up to 300µm. The achieved results exhibit a remarkably good response for temperature sensing up to 650°C.This work has been supported by the projects TEC2013-47264-C2-1-R, TEC2016-76021-C2-2-R and grant BES-2014-069736 of the Spanish government and by the Parliament of Cantabria postdoc grant

Smart material using fiber Bragg grating transducers and shape memory alloy actuators

A structure based on a smart material and a PID control loop is presented in this paper. A glass fiber reinforced plastic material is instrumented with Fiber Bragg Gratings (FBG) and Shape Memory Alloy (SMA) actuators. The smart material and the smart structure are both successfully checked by being subjected to different operational conditions at the laboratory. Very good responses are obtained under both slow and quicker varying conditions.This work has been supported by the Spanish TEC2010-20224-C02-02 project and grant AP2009-140

Curvature sensor based on In-fiber Mach-Zehnder interferometer inscribed with femtosecond laser

In this paper, an In-fiber Mach-Zehnder interferometer inscribed by femtosecond laser for curvature sensing has been designed and manufactured. Its operating principle consists of a secondary waveguide inscription working as a sensing arm. This waveguide has been manufactured using asymmetric structures with an average refractive index change of 1.1 × 10-2 in its guiding section measured by refracted near-field profilometry. The overall arm/cladding index difference is higher than its core/cladding counterpart, which is a suggested condition for device operation following preliminary simulations. The manufactured Mach-Zehnder interferometer exhibits a linear response to bending radius that is also dependent on an established bending axis. Sensitivity has been measured up to 9.49 nm/m-1 for curvature ranges from 0 to 14 m-1. Simulation results using the beam propagation method and conformal mapping transformation to convert bending action into a tilt refractive index agree with experimental results for the same index parameters. Preliminary temperature test shows a remarkable cross sensitivity of 0.0024(3)m-1/-C up to 180 -C.This work has been supported by the pro-jects TEC2013-47264-C2-1-R, TEC2016-76021-C2-2-R (AEI/FEDER, UE) financed with FEDER funds, and grant BES-2014-069736 of the Spanish government and by the Parliament of Cantabria postdoc grant

Time- and Amplitude-Controlled Power Noise Generator against SPA Attacks for FPGA-Based IoT Devices

Power noise generation for masking power traces is a powerful countermeasure against Simple Power Analysis (SPA), and it has also been used against Differential Power Analysis (DPA) or Correlation Power Analysis (CPA) in the case of cryptographic circuits. This technique makes use of power consumption generators as basic modules, which are usually based on ring oscillators when implemented on FPGAs. These modules can be used to generate power noise and to also extract digital signatures through the power side channel for Intellectual Property (IP) protection purposes. In this paper, a new power consumption generator, named Xored High Consuming Module (XHCM), is proposed. XHCM improves, when compared to others proposals in the literature, the amount of current consumption per LUT when implemented on FPGAs. Experimental results show that these modules can achieve current increments in the range from 2.4 mA (with only 16 LUTs on Artix-7 devices with a power consumption density of 0.75 mW/LUT when using a single HCM) to 11.1 mA (with 67 LUTs when using 8 XHCMs, with a power consumption density of 0.83 mW/LUT). Moreover, a version controlled by Pulse-Width Modulation (PWM) has been developed, named PWM-XHCM, which is, as XHCM, suitable for power watermarking. In order to build countermeasures against SPA attacks, a multi-level XHCM (ML-XHCM) is also presented, which is capable of generating different power consumption levels with minimal area overhead (27 six-input LUTS for generating 16 different amplitude levels on Artix-7 devices). Finally, a randomized version, named RML-XHCM, has also been developed using two True Random Number Generators (TRNGs) to generate current consumption peaks with random amplitudes at random times. RML-XHCM requires less than 150 LUTs on Artix-7 devices. Taking into account these characteristics, two main contributions have been carried out in this article: first, XHCM and PWM-XHCM provide an efficient power consumption generator for extracting digital signatures through the power side channel, and on the other hand, ML-XHCM and RML-XHCM are powerful tools for the protection of processing units against SPA attacks in IoT devices implemented on FPGAs.Junta de AndaluciaEuropean Commission B-TIC-588-UGR2

Quasidistributed fiber sensor for precast concrete structures monitoring

The prestressing force is transferred to the concrete during the slack period of precast concrete structures fabrication. To contribute to a better understanding of the armor compliant behaviors during the mentioned process, a custom quasidistributed Bragg Grating optical fiber sensor system is designed, fabricated and embedded into a prestressed concrete prismatic beam. The experimental works, the results, their discussion and finally the obtained conclusions are presented in this paper.This work has been supported by the the project TEC2010-20224-C02- 02 and the grant AP2009-140