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Robert H Wood - One of the best experts on this subject based on the ideXlab platform.
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electrical Conductances of aqueous electrolytes at high temperatures limiting mobilities of several ions including the proton and hcl dissociation constant
Journal of Molecular Liquids, 2017Co-Authors: Victor N Balashov, Lubomir Hnedkovsky, Robert H WoodAbstract:The empirical equation of R.H. Wood for limiting Equivalent NaCl Conductance and a set of equations for a proton and other ions in the aqueous solutions HCl, LiCl, NaCl, KCl, Li2SO4, K2SO4 and mixtures H2SO4–Na2SO4–H2O are revisited and compared with equations of other authors. The Wood equation is unique in an accurate description of the region close to the critical point of water. In this region the decrease in limiting ion mobilities correlate with the increase in water compressibility. In a remarkable way this effect corresponds to the decisive drop in the limiting proton mobility making it similar to the other univalent ions mobilities. Probably, in this water region the critical decrease in the number of hydrogen bonds per water molecule takes place and finally impeding the jump mechanism of proton mobility. The new high temperature data on electrical Conductance of aqueous HCl are represented for molalities 10− 5–10− 3 mol kg− 1 at temperatures 298–673 K and pressures up to 28 MPa. The HCl conductivities have been fitted to the Turq, Blum, Bernard and Kunz equation using Wood mixing rule and mean spherical approximation activity coefficients. At 573–663 K the adjustable parameters are the proton limiting Equivalent Conductance and the HCl dissociation constant. At the measured state point of lowest water density (228.8 kg m− 3; 673 K) the additional account of ion triplets gives good fit to the data.
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Conductance of dilute sodium acetate solutions to 469 k and of acetic acid and sodium acetate acetic acid mixtures to 548 k and 20 mpa
Journal of Solution Chemistry, 2002Co-Authors: G H Zimmerman, Robert H WoodAbstract:In order to obtain accurate association constants for sodium acetate, a very precise flow method was used to measure the electrical conductivity of dilute aqueous solutions of sodium acetate at ambient conditions and 469 K and 20 MPa. Measurements at ambient conditions, 469 and 548 K and 20 MPa, were also made on sodium acetate/acetic acid mixtures and acetic acid. In order to determine the limiting the Equivalent Conductances and the association constant for sodium acetate, and dissociation constant for acetic acid, the results were fitted to two modern Conductance equations (Fuoss–Hsia–Fernandez–Prini and Turq–Blum–Bernard–Kunz) with accompanying activity coefficient models (mean spherical approximation and the Debye–Huckel with the Bjerrum distance). The choice of Conductance equation, activity coefficient model, assumed values for the limiting Equivalent Conductance for minor species, and assumed equilibrium constants for minor reactions, did not significantly change the resulting equilibrium constants. The insensitivity of the calculated equilibrium constants to these choices in conjunction with the inherent precision of the flow Conductance technique leads us to believe that the present results are the most accurate sodium acetate ion-pairing constants published to date. Our results for acetic acid are in good agreement with previously published results from other laboratories.
Andrzej Szromba - One of the best experts on this subject based on the ideXlab platform.
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The Unified Power Quality Conditioner Control Method Based on the Equivalent Conductance Signals of the Compensated Load
MDPI AG, 2020Co-Authors: Andrzej SzrombaAbstract:This paper proposes a new control method for a Unified Power Quality Conditioner (UPQC). This method is based on the load Equivalent Conductance approach, originally proposed by Fryze. It can be useful not only for compensation for nonactive current and for improving voltage quality, but it also allows one to perform some unconventional functions. This control method can be performed by extending the orthodox notion of ‘static’ load Equivalent Conductance into a time-variable signal. It may be used to characterize energy changes in the whole UPQC-and-load circuitry. The UPQC can regulate energy flow between all sources and loads being under compensation. They may be located as well for UPQC’s AC-side as DC-side. System works properly even if they switch their activity to work either as loads or generators. The UPQC can operate also as a buffer, which can store/share the in-load generated energy amongst other loads, or it can transmit this energy to the source. Therefore, in addition to performing the UPQC’s conventional compensation tasks, it can also serve as a local energy distribution center.
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unified power quality conditioner controlled with the use of load Equivalent Conductance signal
2019 15th Selected Issues of Electrical Engineering and Electronics (WZEE), 2019Co-Authors: Andrzej Szromba, B SysloAbstract:In the paper a new method of controlling of operation of series-parallel active filters UPQC has been presented. The idea of load Equivalent Conductance according to S. Fryze is exploited in the paper. The presented method allows conventional compensation for nonactive component of load current and harmonics in source voltage together with improving the quality of the supply voltage, including sags and swells. In addition a case of pulse distortion arising in source voltage has been analyzed.
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shunt active power filter control using signal of load Equivalent Conductance in asymmetrical three phase systems under nonsinusoidal conditions
International Conference on Signals and Electronic Systems, 2016Co-Authors: Andrzej SzrombaAbstract:Shunt active power filters (SAPF) can be controlled using Conductance signal related to the load active power. The distinctive feature of the considered control method is that certain changes of energy stored in the active filter's reactance elements are utilized as the source of information concerning the load power and then the reference signal for the SAPF action. Particularly difficult SAPF operating conditions can occur in systems with asymmetrical and distorted supply voltages. The paper deals with these problems.
Chunting Mi - One of the best experts on this subject based on the ideXlab platform.
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three level inverter based shunt active power filter in three phase three wire and four wire systems
IEEE Transactions on Power Electronics, 2009Co-Authors: O Vodyakho, Chunting MiAbstract:This paper presents a direct current-space-vector control of an active power filter (APF) based on a three-level neutral-point-clamped (NPC) voltage-source inverter. The proposed method indirectly generates the compensation current reference by using an Equivalent Conductance of the fundamental component using APF's dc-link voltage control. The proposed control can selectively choose harmonic current components by real-time fast Fourier transform to generate the compensation current. The compensation current is represented in a rotating coordinate system with chosen switching states from a switching table implemented in a field-programmable gate array. In addition, a three-phase four-wire APF based on a three-level neutral-point-clamped inverter is also presented. The proposed APF eliminates harmonics in all three phases as well as the neutral current. A three-phase three-wire NPC inverter system can be used as a three-phase four-wire system since the split dc capacitors provide a neutral connection. To regulate and balance the split dc-capacitor voltages, a new control method using a sign cubical hysteresis controller is proposed. The characteristics of the APF system with an LCL-ripple filter are investigated and compared with traditional current control strategies to evaluate the inherent advantages. The simulation and experimental results validated the feasibility of the proposed APF.
Brian J Teppen - One of the best experts on this subject based on the ideXlab platform.
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quantitation and measurement of Equivalent Conductance of unidentified analytes by suppressed ion chromatography using conductivity detection
Microchemical Journal, 1992Co-Authors: Tianjia Tang, David M Miller, Brian J TeppenAbstract:Abstract Suppressed ion chromatography with conductivity detection was used to quantify organic anions in solution. A procedure is described whereby the normality and the Equivalent Conductance of unidentified analyte ions can be determined with an accuracy of greater than 90% using two different regenerants but only a single eluent. The proposed method is based on the fact that the conductivity detector's response is directly proportional to the concentrations of both the analyte and its counterions, which in suppressed IC are supplied by the regenerant. While results for monoprotic acids were excellent, results for polyprotic acids were less satisfactory, perhaps due to incomplete dissociation of the analyte.
E S Kuh - One of the best experts on this subject based on the ideXlab platform.
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stepwise Equivalent Conductance circuit simulation technique
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 1993Co-Authors: Shen Lin, E S Kuh, Malgorzata MareksadowskaAbstract:A circuit simulation technique based on a stepwise Equivalent Conductance model of a nonlinear resistive device is introduced. The major advantage of this technique is that it eliminates the need to employ Newton-Raphson iterations for the implicit integration. The technique, when applicable, is consistent, absolutely stable, and convergent. It is demonstrated that a second order of accuracy (the local truncation error for integration is of the cubic order of the time step used) is achieved by solving linear equations for each integration step. When applied to digital MOS circuits, the technique takes advantage of the fact that voltage waveforms can be modeled to a good approximation as piecewise-linear functions and thus provides further speedup in the simulation. The program, called SWEC, has been implemented, and has proved to be accurate and efficient on a large number of circuit examples. The results are compared with those for Relax2.3.iSPLICE3.0 XPsim. and SPECS2. >
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pade approximation applied to transient simulation of lossy coupled transmission lines
IEEE Multi-Chip Module Conference, 1992Co-Authors: S Lin, E S KuhAbstract:A new approach for transient simulation of lossy coupled transmission lines terminated in arbitrary nonlinear elements is presented. The approach is based on convolution simulation. The multiconductor lines are first decoupled to obtain modal functions. Using the Pade approximations of each modal function, the authors derive a recursive convolution formulation, which greatly reduces the computation used to perform convolutions. The approach can handle general coupling situations; no assumption on the simulated circuits is introduced. The approach was implemented in the Stepwise Equivalent Conductance MOS timing simulator, SWEC. The key feature of SWEC is that Newton-Raphson iteration is not needed for the implicit integration of a circuit even with lossy lines terminated in nonlinear elements. The comparisons with SPICE3.e indicated that SWEC can be one to two orders of magnitude faster. >
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swec a step wise Equivalent Conductance timing simulator for cmos vlsi circuits
European Design Automation Conference, 1991Co-Authors: Shen Lin, Malgorzata Mareksadowska, E S KuhAbstract:Timing simulation has always been considered a crucial step in digital VLSI circuit designs. Many researchers have addressed the issues of time efficiency vs. accuracy by using simpler device models and by simplifying the numerical algorithms. StepWise Equivalent Conductance (SWEC) simulation technique, first proposed in [1], is an alternative which approximates the nonlinear transfer characteristic of the transistor with stepwise constant Conductances. In this paper we demonstrate that the time step can be controlled to provide the necessary accuracy in the implicit integration algorithm. A timing simulator has been built based on this principle. The simulator can handle very large CMOS designs. Comparisons have been made with XPsim [2] and SPECS2 [3] using several examples. The results indicate that SWEC exhibits far better efficiency and accuracy.