1,113 research outputs found
A Voltage Calibration Chain for Meters Used in Measurements of EV Inductive Power Charging
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
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
Impact of DC Transient Disturbances on Harmonic Performance of Voltage Transformers for AC Railway Applications
This paper analyzes the impact of typical DC transient events occurring in railway grids on the frequency performance of instrument transformers (ITs) installed onboard trains and in AC substations for power quality (PQ) applications. PQ monitoring in railway systems is an issue of great interest because it plays a key role in the improvement of energy efficiency. The measurement chain for the PQ measurements, at 15 kV at 16.7 Hz and 25 kV at 50/60 Hz, commonly includes ITs to scale the voltage to levels fitting the input of the measurement units. Nevertheless, the behavior of ITs in the presence of PQ phenomena represents an open issue from a normative point of view, even for those installed in conventional AC power supply systems. In this context, the paper presents a possible definition of DC transient disturbances test waveforms, a measurement procedure, and a setup to assess the impact of these disturbances on the harmonic performances of ITs for railway systems. Preliminary experimental tests carried out on two commercial ITs under wide ranges of variation for the amplitude and the time duration of DC disturbances show that, in some cases, the error introduced in harmonic measurements can exceed 100%
Novel perspectives in redox biology and pathophysiology of failing myocytes: modulation of the intramyocardial redox milieu for therapeutic interventions - A review article from the Working Group of Cardiac Cell Biology, Italian Society of Cardiology
The prevalence of heart failure (HF) is still increasing worldwide, with enormous human, social, and economic costs, in spite of
huge efforts in understanding pathogeneticmechanisms and in developing effective therapies that have transformed this syndrome
into a chronic disease. Myocardial redox imbalance is a hallmark of this syndrome, since excessive reactive oxygen and nitrogen
species can behave as signaling molecules in the pathogenesis of hypertrophy and heart failure, leading to dysregulation of cellular
calcium handling, of the contractile machinery, of myocardial energetics and metabolism, and of extracellular matrix deposition.
Recently, following new interesting advances in understanding myocardial ROS and RNS signaling pathways, new promising
therapeutical approaches with antioxidant properties are being developed, keeping in mind that scavenging ROS and RNS tout
court is detrimental as well, since these molecules also play a role in physiological myocardial homeostasis
Carba-D,L-allal- and -D,L-galactal-derived vinyl N-nosyl aziridines as useful tools for the synthesis of 4-deoxy-4-(N-nosylamino)-2,3-unsaturated-5a-carbasugars
The novel carba-D,L-allal- and carba-D,L-galactal-derived vinyl N-nosyl aziridines were prepared and the regio- and stereoselective behavior in opening reactions with O- and N-nucleophiles examined. The carbaglycosylating ability of the novel aziridines, as deduced by the amount of 1,4-addition products (1,4-regioselectivity) obtained in the acid-catalyzed methanolysis taken as a model reaction, is similar or superior to that observed with the corresponding carba-D,L-allal- and -D,L-galactal-derived vinyl epoxides, respectively. In all 1,2- and 1,4-addition products obtained, a –(N-nosylamino) group is regio- and stereoselectively introduced at the C(4) carbon of a 1,2- or 2,3-unsaturated carbasugar, susceptible to further elaborations toward aminocyclitol derivatives. The stereoselective synthesis of the corresponding, enantiomerically pure carba-D,L-allal- and -D,L-galactal-derived vinyl N-acetyl aziridines is also described
FPGA-based real time compensation method for medium voltage transducers
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
One-pot multi-enzymatic synthesis of the four stereoisomers of 4-methylheptan-3-ol
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
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