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Operational Performance and Weld Bead Characteristics of Experimental Tubular-Wires for Underwater Welding
PublikacjaAiming to evaluate new formulations and their operational behavior underwater, two experimental tubular wires with different chemical compositions in their internal flux were initially manufactured, employing a pilot machine and a unique manufacturing process. Weld beads were deposited on a plate placed in a flat position inside a tank using a mechanized system and the IMC 300 welding power source. The work was done at a depth...
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Broadband Modeling of Motor Cable Impact on Common Mode Currents in VFD
PublikacjaExamination of conducted EMI generation and propagation in AC motor drives fed by frequency converter requires to consider parasitic capacitances in converters, motor windings and feeding cables to be taken into account. AC motor winding voltage transients and related common mode currents are significantly correlated with resonance effects occurring in converter's load circuits. Intensity levels of these phenomena depend...
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A measurement method for capacitive sensors based on a versatile direct sensor-to-microcontroller interface circuit
PublikacjaIn the paper, there is presented a new time-domain measurement method for determining the capacitance values of capacitive sensors, dedicated, among others, to capacitive relative humidity sensors. The method is based on a versatile direct sensor-to-microcontroller interface for microcontrollers with internal analog comparators (ACs) and with precision voltage reference sources, e.g. digital-to-analog converters (DACs). The reference...
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An Overview of Bidirectional EV Chargers: Empowering Traction Grid-Powered Chargers
PublikacjaIn recent years, the number of electric vehicles has been at least doubling year after year. As a result, today electric vehicles already account for approximately 10% of the global automotive market, which positively affects environment in urbanized areas. However, to take full advantage of the EV integration it is necessary to use renewable sources for their charging; optimally place charging stations/terminals; optimally manage...
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System of protection against electric shock for circuits with power electronics converters
PublikacjaModern low voltage circuits are very often equipped with power electronics converters, therefore in these circuits non-sinusoidal earth currents (touch currents) may occur. For non-sinusoidal currents safety criteria should be modified. This paper presents these modified criteria and a computer system of protection against electric shock which can be implemented in circuits with power electronics converters. The system is based...
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Study of Direct Methanol Fuel Cell Process Dynamics Using Dynamic Electrochemical Impedance Spectroscopy
PublikacjaA new technique, which was developed to characterize the direct methanol fuel cell under work conditions, has been presented in this paper. The impedance measurements were made using dynamic electrochemical impedance spectroscopy research technique in the galvanostatic mode, using multiple sinusoidal excitation. Obtained results show, that together with an increase of the temperature and working load, the global impedance...
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Modelling of MV and HV Cable Lines
PublikacjaOverhead and cable lines are fundamental elements of power systems. Participation of cable lines is smaller and their percentage decreases as voltage is increased. HV cable lines are often built with the use of cables which are composed of coaxial metallic sheaths. Such cables are also often used in MV networks. The sheath may operate in different confgurations. In the case of Polish MV network the sheaths are earthed at both ends....
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EMC disturbances in connection of driving system
PublikacjaIt is known the steep voltage changes caused by IGBT frequency inverters may cause some electromagnetic problems in driving system. Special dU/dt type as well as sinusoidal filters are used in order to limit the level of the disturbances. The paper presents investigation results of EMC disturbances in inverter supplied induction motor. Experiments have proved that disturbances in current connection differ essentially. Important...
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A predictive estimation based control strategy for a quasi-resonant dc-link inverter
PublikacjaIn this paper the predictive estimation based control strategy for a quasi-resonant dc link inverter (PQRDCLI) is developed. Instead of direct measurement of dc link input inverter current – its estimation with one step prediction is applied. The PQRDCLI fed induction motor, controlled with a predictive current estimation stabilized inverter output voltage slopes independently of load. Moreover, reduction of overvoltage spikes...
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Elctrochemical oxidation and corrosion resistance of the Ti13Nb13Zr alloy
PublikacjaThis paper presents the results of oxidation and corrosion tests carried out on titanium alloy Ti13Nb13Zr. The oxide film was prepared by electrochemical environment 2M H3PO4 for 30 min and 1 h, at a constant voltage 40V. The tests of corrosion resistance were performed by potentiostatic method in Ringer's solution at different pH values: 7, 5 and 3. The change in an appearance of surface and the increase in corrosion resistance...
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Intelligent turbogenerator controller based on artifical neural network
PublikacjaThe paper presents a desing of an intelligent controller based on neural network (ICNN). The ICNN ensures at the same time two fundamental functions : the maintaining of generator voltage at the desired value and the damping of the electromechanical oscillations. Its performance is evaluted on a single machine infinite bus power system through computer simulations. The dynamic and transient operation of the proposed controller...
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Magnetic field microsensor based on GaAs MESFET
PublikacjaA novel concept of the drain separation design in a horizontally-split-drain GaAs MAGFET sensor, based on epitaxial layer growth, was developed. Proper choice of GaAs/AlAs/GaAs epitaxial layer sequence provided good electrical isolation between the drain regions. The measured leakage current between the drain regions was in the range of nA for up to 2V drain voltage bias difference. Performed analytical and numerical calculations...
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Heat Dissipation from the Power Cable in the Casing Pipe
PublikacjaThe current carrying capacity of a power cable determines its ability to carry a specific current and is related to the efficiency of dissipation of heat generated in the cable laid in a specific environment. The studies were conducted in order to determine how the characteristics of the medium around the cable affected its temperature, and thus the ability of the cable to transmit electricity. The experimentation in the lab and...
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Preparation of nano-tubular oxide layers on titanium alloy Ti13Nb13Zr
PublikacjaThe article presents results of oxidation tests and corrosion investigations of titanium alloy Ti13Nb13Zr preformed at different conditions. The oxide layers have been formed using electrochemical method in 2M H3PO4 + 0,3% HF solution for 30 min. and 1h at 20V constant voltage. The corrosion tests heve been made with poteniodynamic method in Ringer's solution at pH ranged 3 and 7. It has been shown that the nano-oxide films, which...
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Experimental test results of the 150kVA 18-pulse diode rectifier with series active power filter
PublikacjaThe paper presents the control system and selected results of experimental tests of the ac/dc power converter consisting of 18-pulse diode rectifier on the basis of coupled reactors and a serial active power filter. Three configurations of the 150kVA converter were tested experimentally and compared: 18-pulse diode rectifier with and without additional grid reactor and the rectifier integrated with the active power filter. The...
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Control of induction machine supplied by a current source inverter using the multi-scalar transformation and backstepping approach
PublikacjaThe paper describes the voltage control technique of squire-cage induction machines supplied by a current source inverter. The control system is based on new transformation of the electric drive system (machine and inverter) state variables to the multi-scalar variables form. The backstepping approach is used to obtain the feedback control law. The control system contains the structure of the observer...
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Assessment of copper surface coverage with corrosion inhibitor using AFM-based local electrical measurements
PublikacjaThe paper presents a new method of assessment of metal surface coverage with corrosion inhibitor and thus of inhibitor protective performance. It is based on the atomic force microscopy measurement performed in a contact mode. Apart from topography images the proposed approach allows acquisition of local DC maps and local electrical impedance spectra via application of DC bias voltage or AC perturbation signal between the conductive...
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EHV transmission lines wires location on line operation issues - case studies
PublikacjaTransmission lines towers construction affects the line parameters and influences on its operation in the future. Misguided design of the tower can lead to serious problems such as overvoltages, electric arc extinction difficulties, voltage asymmetry, resonance phenomena or increasing of magnetic field near the line. The paper points out those threats on example of 400 kV double circuit overhead transmission line with shunt reactors....
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Remote current measurement with FPGA digital processing
PublikacjaThe work presents an implementation of a modular measurement and control systemthat controls variants of mains supply of 230V electrical equipment. The system allowsto supervise power consumption in the office electronic equipment. The system detectsthe instant of the reduced power consumption by a device and makes possible itsswitch-off in order to reduce energy cost. The current is measured with integratedcurrent/voltage converters....
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Assesment of (Mn,Co)3O4powders for possible coating material for SOFC/SOEC interconnects
PublikacjaIn this work (Mn,Co)3O4 spinel powders with different Mn:Co ratio (1:1 and 1:2) and from different commercial suppliers are evaluated for possible powder for production of interconnect coatings. Sinterability of the powders is evaluated on pressed pellets sintered in oxidizing and in reducing/oxidizing atmospheres. For selected powder, coatings are then prepared by the electrophoretic deposition method on Crofer 22 APU stainless...
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Diagnosis of bearing damage in induction motors by instantaneous power analysis
PublikacjaResearch of the machine with simulated bearing damages has been carried out, where variable load torque, simulating bearing damage, was introduced. The results show that components which can be used for bearings diagnosis appear in the spectrum of the product of current and supply voltage instantaneous values. These components are easier to identify than the components of current spectrum, which have been used so far in diagnostic...
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Potential changes in an electric field and electrolytic corrosion.
PublikacjaSources have been described of corrosively hazardous electric fields and methods of determination of the corrosion hazard to metal structures caused by electrolytic corrosion. Results of potential and impedance investigations in the field of stray currents flowing out of a tram traction and in the presence of a defined electric field of low frequency have been presented. Uncertainties have been indicated relating to the generally...
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Wireless Charging Station Design for Electric Scooters: Case Study Analysis
PublikacjaThis study proposes an example of a wireless charging station design for a small-scale vehicle available on the market. The article analyzes basic transmitter inverter topologies and their compensation methods in terms of flexibility of control, tolerance to uncertainty in positioning, and the possibility of decreasing the integration price. Our comprehensive analysis focuses on the battery voltage range, energy capacity, cost,...
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Using A Particular Sampling Method for Impedance Measurement
PublikacjaThe paper presents an impedance measurement method using a particular sampling method which is an alternative to DFT calculation. The method uses a sine excitation signal and sampling response signals proportional to current flowing through and voltage across the measured impedance. The object impedance is calculated without using Fourier transform. The method was first evaluated in MATLAB by means of simulation. The method was...
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Al-DIAMOND SCHOTTKY TUNNEL DIODES WITH BARRIER HEIGHT CONTROL
PublikacjaFew-nanometer-thick very highly boron-doped p-type layers were fabricated at metal-semiconductor interfaces of Schottky barrier diodes formed with aluminum on polycrystalline diamond. Preliminary results show that hermionically-assisted tunneling mechanism results in lower voltage drops at forward biasing of these diodes than expected for the Al-diamond metal-semiconductor potential barrier B. The effective barrier height Bpeff...
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Effect of underwater local cavity welding method conditions on diffusible hydrogen content in deposited metal
PublikacjaOne of the methods with great potential for applications in underwater repairs is local cavity welding. In local cavity method, cooling conditions and diffusible hydrogen amount in weld metal are nearly the same as those existed during welding in the air. This paper presents the results of literature survey and preliminary tests of the effect of local cavity welding conditions on diffusible hydrogen amount in a deposited metal....
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Switching Regulation in the Control of 5-Phase Permanent Magnet Synchronous Motor Fed by 3×5 Direct Matrix Converter
PublikacjaMatrix converter is an AC-AC direct power converter comprising of an array of bi- directional switches. It does not require an intermediate DC-link and allows sinusoidal output waveforms with varying amplitudes and frequencies. The configuration of these bi- directional switches decides the number of inputs and outputs...
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Polyarmonic model of synchronous generator for analysis of autonomous power generation systems
PublikacjaAbstract: This paper presents the polyharmonic modelling of synchronous generator (SG) in machine variables. The simple geometry and windings physical layout has been used for inductance calculations of a salient-pole SG. The main advantage of this model is the ease of describing an autonomous power generation system (APGS) in terms of its topology and thus providing effective analysis at the static and dynamic states, both for...
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Particle Image Velocimetry Measurements of Airflow in Electrohydrodynamic Device for Dust Particle Collection
PublikacjaIn this paper the electrohydrodynamic (EHD)device for gas pumping and cleaning is presented. To induce an airflow in this EHD device corona discharge was used. The discharge was generated between the one-sided spike electrodes and the plate electrodes. An asymmetric electric field and generated discharge result in unidirectional gas flow through the EHD device. The current-voltage characteristics were measured and the corona discharge...
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Implementation of DEIS for reliable fault monitoring and detection in PEMFC single cells and stacks
PublikacjaDynamic Electrochemical Impedance Spectroscopy (DEIS) was presented as novel method for diagnostic and monitoring of PEMFC stack and single cells operation. Impedance characteristics were obtained simultaneously with current - voltage characteristics for stack and each individual cell. Impedance measurements were performed in galvanodynamic mode. It allowed to compare performance of each cell and identification of faulty cell operation...
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Particle Image Velocimetry Measurements of Airflow in Electrohydrodynamic Device for Dust Particle Collection
PublikacjaIn this paper the pumping effect of air in the electrohydrodynamic (EHD) device for dust particle collection is presented. To induce an airflow in this EHD device corona discharge was used. The discharge was generated between the one-sided spike electrodes and the plate electrodes. The asymmetric electric field and generated discharge resulted in a unidirectional airflow through the EHD device. The current-voltage characteristics...
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Evaluation Of Single Pole Auto-Reclosing Effectiveness With Nonlinear Secondary Arc Model
PublikacjaThe paper discusses two evaluation methods of single pole auto-reclosing process effectiveness in HV transmission lines. Secondary arc current and recovery voltage results obtained by load flow calculation are compared to the results obtained by the time domain simulations. Moreover, a non-linear secondary arc implementation is presented. The authors indicate, that precise representation of secondary electric arc leads to more...
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Asymmetrical Modes in Polyphase Motors and Drives
PublikacjaThe effect of power supply and/or motor asymmetry on the phase-load distribution and the ripple of electromagnetic torque in a polyphase drive is studied by the method of symmetrical components. It is shown that the presence of asymmetry causes the mapping of all harmonics in the supply voltage into all planes of symmetrical components and eliminates the possibility of independent control of harmonics. The dynamic model of a five-phase...
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Effect of the let-through energy of overcurrent protective devices on the temperature of conductors during short-circuits
PublikacjaThe scope of the verification of low-voltage systems covers the earth fault loop impedance measurement. This measurement is usually performed with the use of low-value current meters, which force a current many times lower than the one occurring during a real short-circuit. Therefore, the international standard recommends consideration of the increase of resistance of conductors with the increase of temperature, which may occur...
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Application of Barkhausen effect in the impact assessment of welding to internal stress distribution in steel
PublikacjaThe paper presents identification method of internal stresses in plane steel elements in the chase of deliverance and welding assembly. The assessment was made by means of a non-destructive experimental method based on measurements incorporating local external magnetic field and the measurement of induced voltage, including Barkhausen noise. This method allows a degradation assessment due to internal and external actions, causing...
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Application of Barkhausen effect in the impact assessment of welding to internal stress distribution in steel
PublikacjaThe paper presents identification method of internal stresses in plane steel elements in the chase of deliverance and welding assembly. The assessment was made by means of a non-destructive experimental method based on measurements incorporating local external magnetic field and the measurement of induced voltage, including Barkhausen noise. This method allows a degradation assessment due to internal and external actions, causing...
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Automatic tuning of a resonant circuit in wireless power supply systems for biomedical sensors
PublikacjaIn this paper, a tuning method of a resonant circuit suited for wireless powering of miniature endoscopic capsules is presented and discussed. The method allows for an automatic tuning of the resonant frequency and matching impedance of a full wave rectifier loading the resonant circuit. Thereby, the receiver tunes so as to obtain the highest power efficiency under given conditions of transmission. A prototype receiver for wireless...
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Secondary arc modelling for single pole reclosing analyses
PublikacjaThe paper discusses two evaluation methods of single pole auto-reclosing process effectiveness in HV transmission lines. Secondary arc current and recovery voltage calculation results obtained by load flow calculation are compared to the results obtained by the time domain simulations. Moreover, a nonlinear secondary arc model implementation is presented. The paper presents the study results for the three types of EHV transmission...
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Filtering EBG Structures Implemented in Coplanar Waveguide Feedline of Planar Slot Antenna
PublikacjaA novel compact dual-band slot antenna fed by a coplanar waveguide (CPW) incorporating electromagnetic band gap (EBG) structures has been proposed. At first, a classic wideband slot antenna fed by a CPW, dedicated to work in 2 ÷ 18 GHz band, has been designed. Subsequently, by adding simple EBG filtering structures into a CPW feedline, a dual-band performance ranging from 2.5 to 5.3 GHz and from 13.5 to 16.3 GHz, with the voltage...
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Application of sliding switching functions in backstepping based speed observer of induction machine
PublikacjaThe paper presents an analysis of the speed observer which is based on the backstepping and sliding mode approach. The speed observer structure is based on the extended mathematical model of an induction machine. The observer structure is based on the measured phase stator currents and transformed to ( αβ ) coordinate system. The stator voltage vector components are treated as known values. Additionally, such an observer structure...
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Cross-Bonding of MV Cable Lines for Energy Losses Decrease
PublikacjaCurrently, almost all medium voltage cable lines (MV) operate with the return wires earthed at both ends of the cable. Such a way of operation causes that during normal states of operation as well as during disturbances, e.g. short-circuits, in the return wires induce currents whose values mainly depend on the currents flowing in the phase wires. These currents in normal operating states are a source of additional energy losses...
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Performance Analysis of the "Intelligent" Kirchhoff- Law - Johnson-Noise Secure Key Exchange
PublikacjaThe Kirchhoff-law - Johnson-noise (KLJN) secure key distribution system provides a way of exchanging theoretically secure keys by measuring random voltage and current through the wire connecting two different resistors at Alice’s and Bob’s ends. Recently new advanced protocols for the KLJN method have been proposed with enhanced performance. In this paper, we analyze the KLJN system and compare with the „intelligent” KLJN (iKLJN)...
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Photoelectrochemical properties of BIMEVOX (ME=Cu, Zn, Mn) electrodes in contact with aqueous electrolyte
PublikacjaLayered oxide Bi4O2O11 and mixed oxides of bismuth, vanadium and a third metal (ME = Cu, Zn, Mn) were synthesized and characterized using XRD, Raman and SEM. The energy band gap (Eg) of samples determined using UV–VIS reflectance spectra equals to 2.46, 2.34, 2.27 and 2.18 eV for Bi4V2O11, BICUVOX (Bi2V1 − xCuxO5.5 − 3x/2), BIZNVOX (Bi2V1 − xZnxO5.5 − 3x/2) and BIMNVOX (Bi2V1 − xMnxO5.5 − x/2) (x = 0.1), respectively. Open circuit...
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Self-Testing of Analog Parts Terminated by ADCs Based on Multiple Sampling of Time Responses
PublikacjaA new approach for self-testing of analog parts terminated by analog-to-digital converters in mixed-signal electronic microsystems controlled by microcontrollers is presented. It is based upon a new fault diagnosis method using a transformation of the set of voltage samples of the time response of a tested analog part to a square impulse into localization curves placed in a multidimensional measurement space. The method can be used...
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Time-current tripping characteristics of RCDs for sinusoidal testing current
PublikacjaLow-voltage electrical installations are verified initially – before being put into operation, as well as periodically – during their utilization. According to the IEC standards, the scope of the verification includes measurements of both the tripping current and the disconnection time of residual current devices (RCDs). Experiences in RCDs testing show that disconnection times of two or more similar RCDs can be quite different....
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The Impact of Wind Generation on the Transmission System
PublikacjaThis article has been published to investigate the im-pact of the wind power on the power system- this is a system dependent issue that requires to perform sys-tem specific impact study. This paper discusses the impact of power flow, short circuit current, power quali-ty, voltage stability and the power system during the connection of a wind farm into transmission system. W referacie omówiono wpływ farm wiatrowych na pracę systemu...
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Practical aspects of testing superconducting electromagnets by the capacitor discharge method taking into account the non-linearity of circuit parameters
PublikacjaThe article presents selected issues related to the development and testing of the diagnostics systems dedicated for superconducting electromagnets. The systems were constructed to assess the production quality of superconducting electromagnets of the SIS100 synchrotron, a new accelerator being built as part of the Facility of Antiproton and Ion Research (FAIR). One of the systems is used for automatic checking of electrical connection...
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Control Strategy of a Five-Phase Induction Machine Supplied by the Current Source Inverter With the Third Harmonic Injection
PublikacjaIn the five-phase induction machine (IM), it is possible to better use the electromagnetic circuit than in the three-phase IM. This requires the use of an adequate converter system which will be supplied by an induction machine. The electric drive system described, in this article, includes the five-phase induction machine supplied by the current source inverter (CSI). The proposed novelty—not presented previously—is the control...
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Identification of volatile compounds based on the electrocatalytic gas sensor responses
PublikacjaMeasured response in case of electrocatalytic gas sensors is in form of a voltamperometric characteristic. Current-voltage (I-V) response shape depends on the gas type and its concentration. Such response contains significantly more information comparing with typical electrochemical sensors, but is quite difficult to analyze. When I-V curve contains current peaks, position of such peaks can be used...
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Optical activity and electro-optic effect of l-arginine doped KDP single crystals
PublikacjaWe have used the modified polarimetric methods to study optical activity (OA) in the potassium dihydrogenphosphate (KDP) crystals doped with 0.7, 1.4 and 3.8 wt% L-arginine (L-arg) amino acid. Crystals were grown by the temperature reduction method. Small changes of the absolute eigen waves ellipticity and OA values in doped crystals were noted. We have experimentally determined the signs of OA in the [1 00] and [01 0] directions...