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The simultaneous determination of chemical vapor-generating elements involving derivatization is difficult even by inductively coupled plasma optical emission spectrometry or mass spectrometry. This study proposes a new direct liquid microsampling method for the simultaneous determination of As, Bi, Se, Te, Hg, Pb, and Sn, using a fully miniaturized set-up based on electrothermal vaporization capacitively coupled plasma microtorch optical emission spectrometry. The method is cost-effective, free from non-spectral interference, and easy to run by avoiding derivatization. The method involves the vaporization of analytes from the 10 µL sample and recording of episodic spectra generated in low-power (15 W) and low-Ar consumption (150 mL min−1) plasma microtorch interfaced with low-resolution microspectrometers. Selective vaporization at 1300 °C ensured the avoidance of non-spectral effects and allowed the use of external calibration. Several spectral lines for each element even in the range 180–210 nm could be selected. Generally, this spectral range is examined with large-scale instrumentation. Even in the absence of derivatization, the obtained detection limits were low (0.02–0.75 mg kg−1) and allowed analysis of environmental samples, such as cave and river sediments. The recovery was in the range of 86–116%, and the accuracy was better than 10%. The method is of general interest and could be implemented on any miniaturized or classical laboratory spectrometric instrumentation.
Simion Angyus; Erika Levei; Dorin Petreus; Radu Etz; Eniko Covaci; Oana Moldovan; Michaela Ponta; Eugen Darvasi; Tiberiu Frentiu. Simultaneous Determination of As, Bi, Sb, Se, Te, Hg, Pb and Sn by Small-Sized Electrothermal Vaporization Capacitively Coupled Plasma Microtorch Optical Emission Spectrometry Using Direct Liquid Microsampling. Molecules 2021, 26, 2642 .
AMA StyleSimion Angyus, Erika Levei, Dorin Petreus, Radu Etz, Eniko Covaci, Oana Moldovan, Michaela Ponta, Eugen Darvasi, Tiberiu Frentiu. Simultaneous Determination of As, Bi, Sb, Se, Te, Hg, Pb and Sn by Small-Sized Electrothermal Vaporization Capacitively Coupled Plasma Microtorch Optical Emission Spectrometry Using Direct Liquid Microsampling. Molecules. 2021; 26 (9):2642.
Chicago/Turabian StyleSimion Angyus; Erika Levei; Dorin Petreus; Radu Etz; Eniko Covaci; Oana Moldovan; Michaela Ponta; Eugen Darvasi; Tiberiu Frentiu. 2021. "Simultaneous Determination of As, Bi, Sb, Se, Te, Hg, Pb and Sn by Small-Sized Electrothermal Vaporization Capacitively Coupled Plasma Microtorch Optical Emission Spectrometry Using Direct Liquid Microsampling." Molecules 26, no. 9: 2642.
A phase-shift full bridge converter is analyzed in detail in continuous conduction mode for one switching cycle for both the leading and lagging legs of the primary bridge. The objective of the study is to determine how the stray capacitance of the transformer, and the capacitances of the diodes in the bridge rectifier affect the converter functionality. Starting from some experimental results, Laplace equivalent circuit models and describing equations are derived for each significant time interval during the switching cycle and are validated through simulations and experimental measurements. The resulting equations are of great interest in the high-power density domain because they can be used to design a clamping circuit for the output rectifier bridge accurately.
Dorin Petreus; Radu Etz; Toma Patarau; Ionut Ciocan. Comprehensive Analysis of a High-Power Density Phase-Shift Full Bridge Converter Highlighting the Effects of the Parasitic Capacitances. Energies 2020, 13, 1439 .
AMA StyleDorin Petreus, Radu Etz, Toma Patarau, Ionut Ciocan. Comprehensive Analysis of a High-Power Density Phase-Shift Full Bridge Converter Highlighting the Effects of the Parasitic Capacitances. Energies. 2020; 13 (6):1439.
Chicago/Turabian StyleDorin Petreus; Radu Etz; Toma Patarau; Ionut Ciocan. 2020. "Comprehensive Analysis of a High-Power Density Phase-Shift Full Bridge Converter Highlighting the Effects of the Parasitic Capacitances." Energies 13, no. 6: 1439.
The study provides a comparative analysis of the energy production of a 3 kW peak PV array connected in an islanded microgrid, in correlation with solar radiation and ambient temperature measurements. The experimental system is located in Cluj-Napoca Romania and was monitored during the year 2017, based on a graphical user interface. It was also evaluated the capability to predict the PV energy production by using the PV*SOL simulation software and an analytical model, developed at the Technical University of Cluj-Napoca. As input data in the analytical model was used the measured solar radiation and ambient temperature while in the simulations was used alternatively measured data and average meteorological data available in the software database. Besides energy production it was compared the solar radiation on the tilted plane of the PV panels, the PV panel's temperature and the system efficiency. For the predictions accuracy evaluation it was used the weighted mean absolute error based on total energy production, which was found to be lower than 1%, in good agreement with the values reported in literature. The outcomes of this study are valuable for expanding the PV installations in this area and for predictive energy management developments.
Dorin Petreuş; Mugur Bălan; Octavian Pop; Radu Etz; Toma Patărău. Evaluation of the PV energy production determined by measurements, simulation and analytical calculations. E3S Web of Conferences 2019, 85, 04002 .
AMA StyleDorin Petreuş, Mugur Bălan, Octavian Pop, Radu Etz, Toma Patărău. Evaluation of the PV energy production determined by measurements, simulation and analytical calculations. E3S Web of Conferences. 2019; 85 ():04002.
Chicago/Turabian StyleDorin Petreuş; Mugur Bălan; Octavian Pop; Radu Etz; Toma Patărău. 2019. "Evaluation of the PV energy production determined by measurements, simulation and analytical calculations." E3S Web of Conferences 85, no. : 04002.