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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.
A novel microgrid emulator used to test multiple microgrid configurations and energy management control strategies is presented. The system includes Hardware-In-the-Loop (HIL) emulators for geothermal and biogas energy sources. It also includes actual photovoltaic energy together with a lead acid battery bank for storage and it is controlled by a two level control system. The control system consists of a primary level voltage-reactive power and frequency-active power and a secondary level energy management algorithm based on the balance between the power produced by the renewable energy generators, state of charge of the battery bank and the loads. The energy management control strategy is based on cycle-charging the batteries at a reference value in order to efficiently use the available resources. The primary energy source is considered the geothermal energy, while the most cost effective one is the photovoltaic energy. A buffer zone is kept in the battery bank in order to store as much energy produced by the photovoltaic system as possible. The presented microgrid, used for testing the energy management strategies, employs emulators for the geothermal and biogas generators; however, the results are relevant and can be scaled for a real-life microgrid.
D. Petreus; R. Etz; T. Patarau; M. Cirstea. An islanded microgrid energy management controller validated by using hardware-in-the-loop emulators. International Journal of Electrical Power & Energy Systems 2018, 106, 346 -357.
AMA StyleD. Petreus, R. Etz, T. Patarau, M. Cirstea. An islanded microgrid energy management controller validated by using hardware-in-the-loop emulators. International Journal of Electrical Power & Energy Systems. 2018; 106 ():346-357.
Chicago/Turabian StyleD. Petreus; R. Etz; T. Patarau; M. Cirstea. 2018. "An islanded microgrid energy management controller validated by using hardware-in-the-loop emulators." International Journal of Electrical Power & Energy Systems 106, no. : 346-357.
This study presents an investigation concerning the conversion of solar radiation into heat, cold, and electricity on the facades of virtual buildings located in four different cities that correspond to different climatic conditions. Two of the cities are in Eastern Europe, Romania, one city is situated in Western Europe, Spain, and one city is on the western coast of the United States. Four different solar active applications integrated in the facades were investigated: heating based on flat solar collectors, cooling based on a LiBr-H2O absorption cycle, photovoltaic conversion of solar radiation in electricity, and conversion of heat into electricity based on an organic Rankine cycle. The facades most suitable for investments in the solar active applications were recommended and it was found that both location and the type of application were influencing such recommendations. For both locations in Romania the facade facing west was recommended for all types of applications. For the location in Spain, for both heating and cooling, the first recommendation is the facade facing east and the second recommendation is the facade facing south. Although for electrical applications, the first recommendation is the facade facing south, and the second recommendation is the facade facing east. For the location in the United States, for heating and cooling, the first recommendation is the facade facing west, and the second recommendation is the facade facing south. Although, for electrical applications, the first recommendation is the facade facing south, and the second recommendation is the facade facing west.
Paula V. Unguresan; Raluca A. Porumb; Dorin Petreus; Adrian G. Pocola; Octavian G. Pop; Mugur C. Balan. Orientation of Facades for Active Solar Energy Applications in Different Climatic Conditions. Journal of Energy Engineering 2017, 143, 04017059 .
AMA StylePaula V. Unguresan, Raluca A. Porumb, Dorin Petreus, Adrian G. Pocola, Octavian G. Pop, Mugur C. Balan. Orientation of Facades for Active Solar Energy Applications in Different Climatic Conditions. Journal of Energy Engineering. 2017; 143 (6):04017059.
Chicago/Turabian StylePaula V. Unguresan; Raluca A. Porumb; Dorin Petreus; Adrian G. Pocola; Octavian G. Pop; Mugur C. Balan. 2017. "Orientation of Facades for Active Solar Energy Applications in Different Climatic Conditions." Journal of Energy Engineering 143, no. 6: 04017059.
A new temperature control method for a metallic filament used at high temperature values is proposed by the authors in this paper. The filament used is heated by a switch mode power su ...
R. Etz; D. Petreus; T. Frentiu; T. Patarau; C. Orian. An Indirect Method and Equipment for Temperature Monitoring and Control. Advances in Electrical and Computer Engineering 2015, 15, 87 -94.
AMA StyleR. Etz, D. Petreus, T. Frentiu, T. Patarau, C. Orian. An Indirect Method and Equipment for Temperature Monitoring and Control. Advances in Electrical and Computer Engineering. 2015; 15 (4):87-94.
Chicago/Turabian StyleR. Etz; D. Petreus; T. Frentiu; T. Patarau; C. Orian. 2015. "An Indirect Method and Equipment for Temperature Monitoring and Control." Advances in Electrical and Computer Engineering 15, no. 4: 87-94.
This paper presents a novel control and modulation technique applied to a low cost single stage solar micro-inverter. Multiple modulation strategies are analysed and finally an optimal one is proposed and implemented in order to obtain a low total harmonic distortion factor and a power factor close to unity of the current supplied to the grid. The luminosity step time response of the system is improved using two analog control loops: a hysteresis current mode control loop and a voltage loop on the input solar panel voltage. A MPPT power loop is also implemented in order to harvest maximum energy from the solar panel. The simulation times of the entire system is improved by implementing an average model for the inverter. In this way multiple control strategies and MPPT algorithms can be tested and compared in a shorter time. The experimental results validate the theoretical and simulated ones.
Dorin Petreuş; Stefan Daraban; Ionut Ciocan; Toma Patarau; Cristina Morel; Mohamed Machmoum. Low cost single stage micro-inverter with MPPT for grid connected applications. Solar Energy 2013, 92, 241 -255.
AMA StyleDorin Petreuş, Stefan Daraban, Ionut Ciocan, Toma Patarau, Cristina Morel, Mohamed Machmoum. Low cost single stage micro-inverter with MPPT for grid connected applications. Solar Energy. 2013; 92 ():241-255.
Chicago/Turabian StyleDorin Petreuş; Stefan Daraban; Ionut Ciocan; Toma Patarau; Cristina Morel; Mohamed Machmoum. 2013. "Low cost single stage micro-inverter with MPPT for grid connected applications." Solar Energy 92, no. : 241-255.
This paper is focused on the digital implementation of a voltage and a current loop for a buck converter used in distributed maximum power point systems (DMPPT). It presents the importance of an additional control to help the maximum power point tracking (MPPT) algorithm. The paper gives a detailed small signal analysis and describes the method for compensating the current and voltage loop, making the stability of the system independent of the operating point on the power voltage (P-V) characteristic. The paper also proposes an original Perturb and Observe (P&O) algorithm with variable step size to search a local maximum. The calculation of the step size is independent from the slope of the solar panel's P-V characteristic, making the tracking performances independent of the PV module. Simulation and experimental results are finally provided to verify the performance of the system.
Stefan Daraban; Dorin Petreus; Daniel Moga. Novel Control for a Buck Converter used in a DMPPT System. IFAC Proceedings Volumes 2013, 46, 125 -130.
AMA StyleStefan Daraban, Dorin Petreus, Daniel Moga. Novel Control for a Buck Converter used in a DMPPT System. IFAC Proceedings Volumes. 2013; 46 (6):125-130.
Chicago/Turabian StyleStefan Daraban; Dorin Petreus; Daniel Moga. 2013. "Novel Control for a Buck Converter used in a DMPPT System." IFAC Proceedings Volumes 46, no. 6: 125-130.
This paper introduces a combined analytical and numerical approach in order to study the suitability of a coil array for contactless transfer of the energy needed for the charging of batteries in active transponders. The way in which the geometry of the coil system influences the efficiency of the transfer is analyzed based on flux computation. An array of planar, circularly shaped primary coils is proposed as a solution to transmit the energy to a secondary coil, contained in the active tag, for situations of random placement of the active tag above the coil array. Ill. 19, bibl. 13 (in English; abstracts in English and Lithuanian).DOI: http://dx.doi.org/10.5755/j01.eee.123.7.2372
F. A. Hrebenciuc; D. Moga; D. Petreus; Z. Barabas; R. Moga. Combined Analytical and Numerical Approach to Study Coil Arrays for Contactless Charging of Batteries in Active Transponders. Elektronika ir Elektrotechnika 2012, 123, 37-42 .
AMA StyleF. A. Hrebenciuc, D. Moga, D. Petreus, Z. Barabas, R. Moga. Combined Analytical and Numerical Approach to Study Coil Arrays for Contactless Charging of Batteries in Active Transponders. Elektronika ir Elektrotechnika. 2012; 123 (7):37-42.
Chicago/Turabian StyleF. A. Hrebenciuc; D. Moga; D. Petreus; Z. Barabas; R. Moga. 2012. "Combined Analytical and Numerical Approach to Study Coil Arrays for Contactless Charging of Batteries in Active Transponders." Elektronika ir Elektrotechnika 123, no. 7: 37-42.
This paper presents a digitally controlled step down converter using fuzzy technology designed to be used in renewable energy systems. The fuzzy controller is implemented based on the design of an analog controller and is implemented for verification in Simulink and Psim. After the validation of the model the controller is implemented on a Microchip DSC (Digital Signal Controller).
R. Etz; D. Petreus; D. Moga; M. Abrudean; T. Patarau. Fuzzy Digital Control for DC-DC Converters Used in Renewable Energy Systems. IFAC Proceedings Volumes 2012, 45, 91 -96.
AMA StyleR. Etz, D. Petreus, D. Moga, M. Abrudean, T. Patarau. Fuzzy Digital Control for DC-DC Converters Used in Renewable Energy Systems. IFAC Proceedings Volumes. 2012; 45 (21):91-96.
Chicago/Turabian StyleR. Etz; D. Petreus; D. Moga; M. Abrudean; T. Patarau. 2012. "Fuzzy Digital Control for DC-DC Converters Used in Renewable Energy Systems." IFAC Proceedings Volumes 45, no. 21: 91-96.
C. Morel; R. Vlad; J.-Y. Morel; D. Petreus. Generating chaotic attractors on a surface. Mathematics and Computers in Simulation 2011, 81, 2549 -2563.
AMA StyleC. Morel, R. Vlad, J.-Y. Morel, D. Petreus. Generating chaotic attractors on a surface. Mathematics and Computers in Simulation. 2011; 81 (11):2549-2563.
Chicago/Turabian StyleC. Morel; R. Vlad; J.-Y. Morel; D. Petreus. 2011. "Generating chaotic attractors on a surface." Mathematics and Computers in Simulation 81, no. 11: 2549-2563.
In this paper, a new maximum power point tracking (MPPT) system for photovoltaic applications is presented. The proposed system consists of two analog loops, a current and a voltage loop, built around a boost converter and a digital loop for the computation of the maximum power point. The analog loops provide a fast response to sudden changes of irradiance conditions while the digital loop, enhancing the accuracy, allows the implementation of various MPPT algorithms and facilitates the integration of additional control and monitoring features. Different existing systems are simulated and compared. A small signal model for the proposed system is developed and a novel compensation method is found. The compensation is designed in such a way that it makes the system independent of the input panel used and also of the load connected at the output. In order to have fast simulation results, a macromodel is developed allowing comparison between different algorithms. Furthermore the “perturb and observe” (P&O) algorithm is improved to obtain a better response for changing irradiance conditions.
Dorin Petreuş; Toma Pătărău; Stefan Dărăban; Cristina Morel; Brian Morley. A novel maximum power point tracker based on analog and digital control loops. Solar Energy 2011, 85, 588 -600.
AMA StyleDorin Petreuş, Toma Pătărău, Stefan Dărăban, Cristina Morel, Brian Morley. A novel maximum power point tracker based on analog and digital control loops. Solar Energy. 2011; 85 (3):588-600.
Chicago/Turabian StyleDorin Petreuş; Toma Pătărău; Stefan Dărăban; Cristina Morel; Brian Morley. 2011. "A novel maximum power point tracker based on analog and digital control loops." Solar Energy 85, no. 3: 588-600.
This paper describes bifurcation phenomena of a photovoltaic system. The studied photovoltaic (PV) system includes a solar panel, a boost converter, a maximum power point tracking (MPP ...
C. Morel; D. Petreus; A. Rusu. Application of the Filippov Method for the Stability Analysis of a Photovoltaic System. Advances in Electrical and Computer Engineering 2011, 11, 93 -98.
AMA StyleC. Morel, D. Petreus, A. Rusu. Application of the Filippov Method for the Stability Analysis of a Photovoltaic System. Advances in Electrical and Computer Engineering. 2011; 11 (4):93-98.
Chicago/Turabian StyleC. Morel; D. Petreus; A. Rusu. 2011. "Application of the Filippov Method for the Stability Analysis of a Photovoltaic System." Advances in Electrical and Computer Engineering 11, no. 4: 93-98.
The paper presents a low cost system for wireless monitoring of the progressive loading of lower limb. This system contains a smart device able to measure the plantar pressure, to compare it with predefined levels and to signal the patient in order to avoid excessive loading of the limb in case of patients following post-traumatic rehabilitation.
F. Neaga; D. Moga; D. Petreus; M. Munteanu; N. Stroia. A Wireless System for Monitoring the Progressive Loading of Lower Limb in Post-Traumatic Rehabilitation. VI Latin American Congress on Biomedical Engineering CLAIB 2014, Paraná, Argentina 29, 30 & 31 October 2014 2011, 36, 54 -59.
AMA StyleF. Neaga, D. Moga, D. Petreus, M. Munteanu, N. Stroia. A Wireless System for Monitoring the Progressive Loading of Lower Limb in Post-Traumatic Rehabilitation. VI Latin American Congress on Biomedical Engineering CLAIB 2014, Paraná, Argentina 29, 30 & 31 October 2014. 2011; 36 ():54-59.
Chicago/Turabian StyleF. Neaga; D. Moga; D. Petreus; M. Munteanu; N. Stroia. 2011. "A Wireless System for Monitoring the Progressive Loading of Lower Limb in Post-Traumatic Rehabilitation." VI Latin American Congress on Biomedical Engineering CLAIB 2014, Paraná, Argentina 29, 30 & 31 October 2014 36, no. : 54-59.
A photovoltaic (PV) system, based on a Maximum Power Point Tracking (MPPT) controller that extracts the maximum possible output power from the solar panel is described. Output efficiency of a PV energy system can be achieved only if the system working point is brought near the maximum power point (MPP). The proposed system, making use of several MPPT control algorithms (Perturb and Observe, Incremental conductance, Fuzzy Logic), demonstrates in simulations as well as in real experiments good tracking of the optimal working point
D. Petreus; D. Moga; A. Rusu; T. Patarau; M. Munteanu. Photovoltaic System with Smart Tracking of the Optimal Working Point. Advances in Electrical and Computer Engineering 2010, 10, 40 -47.
AMA StyleD. Petreus, D. Moga, A. Rusu, T. Patarau, M. Munteanu. Photovoltaic System with Smart Tracking of the Optimal Working Point. Advances in Electrical and Computer Engineering. 2010; 10 (3):40-47.
Chicago/Turabian StyleD. Petreus; D. Moga; A. Rusu; T. Patarau; M. Munteanu. 2010. "Photovoltaic System with Smart Tracking of the Optimal Working Point." Advances in Electrical and Computer Engineering 10, no. 3: 40-47.
Faced with numerous challenges raised by the requirements of the modern industries for higher power and higher energy, supercapacitors study started playing an important role in offering viable solutions for some of these requirements. This paper presents the surface redox reactions based modeling in order to study the origin of high capacity of EDLC (electrical double-layer capacitor) for better understanding the working principles of supercapacitors. Some application-dependent sizing methods are also presented since proper sizing can increase the efficiency and the life cycle of the supercapacitor based systems
D. Petreus; D. Moga; R. Galatus; R. A. Munteanu. Modeling and Sizing of Supercapacitors. Advances in Electrical and Computer Engineering 2008, 8, 15 -22.
AMA StyleD. Petreus, D. Moga, R. Galatus, R. A. Munteanu. Modeling and Sizing of Supercapacitors. Advances in Electrical and Computer Engineering. 2008; 8 (2):15-22.
Chicago/Turabian StyleD. Petreus; D. Moga; R. Galatus; R. A. Munteanu. 2008. "Modeling and Sizing of Supercapacitors." Advances in Electrical and Computer Engineering 8, no. 2: 15-22.
In this paper we present the design of electronic ballast for a specific type of fluorescent lamp (Osram 36W) which incorporates dimming control. The achieved results give some new ideas for electronic ballast for 12V operation. A class D inverter is used to provide a dominant characteristic for the proposed topology. Another notable aspect is the use of a single magnetic component (a transformer with leakage inductance). The design and performances are intended to provide a low cost concept suitable for the lamp control
D. Petreus; C. Fărcaș; N. Palaghita; Z. Juhos; I. Ciocan. Electronic Ballast for a Fluorescent Lamp Supplied from a Battery. 2006 1st Electronic Systemintegration Technology Conference 2006, 1, 648 -654.
AMA StyleD. Petreus, C. Fărcaș, N. Palaghita, Z. Juhos, I. Ciocan. Electronic Ballast for a Fluorescent Lamp Supplied from a Battery. 2006 1st Electronic Systemintegration Technology Conference. 2006; 1 ():648-654.
Chicago/Turabian StyleD. Petreus; C. Fărcaș; N. Palaghita; Z. Juhos; I. Ciocan. 2006. "Electronic Ballast for a Fluorescent Lamp Supplied from a Battery." 2006 1st Electronic Systemintegration Technology Conference 1, no. : 648-654.