1,115 research outputs found

    A Voltage Calibration Chain for Meters Used in Measurements of EV Inductive Power Charging

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    The inductive charging of electric vehicles requires specific measurement and calibration systems. In fact, the measurement of power on board involves DC signals, which are superimposed to a significant AC ripple up to or over 150 kHz, depending on the type of charging system. A calibration method that makes use of a phantom power, based on two independent but synchronized circuits, is considered, simulating the charging voltage and current. This paper describes in detail a solution in the realization of the voltage calibration chain, based on the use of a DC voltage calibrator, an injector and a voltage divider.Comment: 2 pages, Conference on Precision Electromagnetic Measurements (CPEM 2018), Paris

    A Method for the Measurement of Digitizers’ Absolute Phase Error

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    A lot of engineering applications, from telecommunications to power systems, require accurate measurement of phase angles. Some of them, like synchrophasor measurement and calibration of instrument transformers with digital output, in order to reach high phase measurement accuracy, require the knowledge of phase error of digitizers. Therefore, in this paper a method for the measurement of digitizers’ absolute phase errors is proposed. It adopts a sinewave and two square waves, that are the digitizer sample clock and a phase reference signal. Combining the measurements of the relative phase differences between the adopted signals it is possible to accurately evaluate the absolute phase error of a digitize

    One-pot multi-enzymatic synthesis of the four stereoisomers of 4-methylheptan-3-ol

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    The use of pheromones in the integrated pest management of insects is currently considered a sustainable and environmentally benign alternative to hazardous insecticides. 4-Methylheptan-3-ol is an interesting example of an insect pheromone, because its stereoisomers are active towards different species. All four possible stereoisomers of this compd. were prepd. from 4-methylhept-4-en-3-one by a one-pot procedure in which the two stereogenic centers were created during two sequential redns. catalyzed by an ene-reductase (ER) and an alc. dehydrogenase (ADH), resp

    FPGA-based real time compensation method for medium voltage transducers

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    open5noSince the increase of the distributed power connected to the medium voltage networks, a capillary monitoring of the power quality becomes essential. This entails the spread of transducers with suitable frequency bandwidths, as required by the relevant standards. The paper describes a real time compensation method for the extension of the frequency bandwidth of medium voltage dividers whose performances do not allow to perform measurements over a wide frequency range. This approach will contribute to keep the costs of this innovation lowopenCrotti, Gabriella; Gallo, Daniele; Giordano, Domenico; Landi, Carmine; Inrim, Mario Luiso2 1Crotti, Gabriella; Gallo, Daniele; Giordano, Domenico; Landi, Carmine; Inrim, Mario Luiso2

    Calibration of Current Transformers in distorted conditions

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    In the context of modern power systems, where there are lots of non-linear loads and generators based on switching power electronics, the accurate measurement of voltage and current harmonics is a key task for the knowledge of the actual state of the network. Voltage and current transducers play a crucial role since they are always the first part of the measurement chain. Currently, classical voltage and current instrument transformers are the most installed transducers, but their performance not always is fully characterized in the presence of distorted waveforms. Therefore, in this paper a calibration setup for the accurate characterization of current transformers with distorted waveforms is presented. System implementation and characterization is presented; then it is employed for the evaluation of the performance of a commercial current transformer in distorted conditions

    SOT-MRAM 300mm integration for low power and ultrafast embedded memories

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    We demonstrate for the first time full-scale integration of top-pinned perpendicular MTJ on 300 mm wafer using CMOS-compatible processes for spin-orbit torque (SOT)-MRAM architectures. We show that 62 nm devices with a W-based SOT underlayer have very large endurance (> 5x10^10), sub-ns switching time of 210 ps, and operate with power as low as 300 pJ.Comment: presented at VLSI2018 session C8-

    Application of computational quantum chemistry to chemical processes involved in mass spectrometry

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    The field of application of mass spectrometry (MS) has increased considerably due to the development of ionization techniques. Other factors that have stimulated the use of MS are the tandem mass spectrometry (MS/MS) and sequential mass spectrometry (MSn) techniques. However, the interpretation of the MS/MS and MSn data may lead to speculative conclusions. Thus, various quantum chemical methods have been applied for obtaining high quality thermochemical data in gas phase. In this review, we show some applications of computational quantum chemistry to understand the formation and fragmentation of gaseous ions of organic compounds in a MS analysis.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)FAPESPCNP

    Asaia, a versatile acetic acid bacterial symbiont, capable of cross-colonizing insects of phylogenetically-distant genera and orders

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    Bacterial symbionts of insects have been proposed for blocking transmission of vector-borne pathogens. However, in many vector models the ecology of symbionts and their capability of cross-colonizing different hosts, an important feature in the symbiotic control approach, is poorly known. Here we show that the acetic acid bacterium Asaia, previously found in the malaria mosquito vector Anopheles stephensi, is also present in and capable of cross-colonizing other sugar-feeding insects of phylogenetically distant genera and orders. PCR, real-time PCR and in situ-hybridization experiments showed Asaia in the body of the mosquito Aedes aegypti and the leafhopper Scaphoideus titanus, vectors of human viruses and a grapevine phytoplasma, respectively. Cross colonization patterns of the body of Ae. aegypti, An. stephensi and S. titanus have been documented with Asaia strains isolated from An. stephensi or Ae. aegypti, and labelled with plasmid- or chromosome-encoded fluorescent proteins (Gfp and DsRed, respectively). Fluorescence and confocal microscopy showed that Asaia, administered with the sugar meal, efficiently colonized guts, male and female reproductive systems and the salivary glands. The ability in cross-colonizing insects of phylogenetically distant orders indicates that Asaia adopts body invasion mechanisms independent from the host biological characteristics. This versatility is an important property for the development of symbiont-based therapies of different vector-borne diseases
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