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Bhim Bali Prasad - One of the best experts on this subject based on the ideXlab platform.
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Electrolytic Conductivity of crystal violet based quaternary ammonium polyelectrolytes in N,N′-dimethylformamide and dimethyl sulfoxide
Canadian Journal of Chemistry, 1997Co-Authors: Meenakshi Singh, Anil Kumar, Shirley Easo, Bhim Bali PrasadAbstract:Electrolytic conductivities of crystal violet based quaternary ammonium polyelectrolytes in very dilute solutions of dimethylformamide and dimethyl sulfoxide at 25 °C have been investigated. The Electrolytic Conductivity (κ) as a function of concentration for systems having a reduced charge density (ξ) greater than unity revealed a very narrow range of linearity in the dilute region. A modest correlation has been made with the counterion condensation and the polycation conformations in order to explain the relative magnitude of limiting equivalent conductivities. Keywords: conductance, polyelectrolyte, aprotic solvent, solvation, counterion condensation.
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Electrolytic Conductivity of the N-Chloranil- and N-Xylylene-Based Polyelectrolytes in Dimethylformamide and Dimethyl Sulfoxide
Journal of Chemical & Engineering Data, 1996Co-Authors: Meenakshi Singh, Bhim Bali PrasadAbstract:Electrolytic conductivities of four typical nitrogen-based polycations, where quaternary nitrogens in the molecular chain are attached with chloranil and xylylene moieties and are interspersed with ethylene, phenothiazine, and bipyridyl (viologen), linkages, have been investigated in dimethylformamide and dimethyl sulfoxide at 25 °C. The Electrolytic Conductivity as a function of concentration for systems with high charge density revealed a very narrow range of linearity in the dilute region. An empirical approach based on the Lattey equation is found suitable for the determination of the limiting mobilities of the polyions.
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Electrolytic Conductivity of Crystal Violet-Based Quaternary Ammonium Polyelectrolytes in Propylene Carbonate and Sulfolane
Journal of Chemical & Engineering Data, 1995Co-Authors: Bhim Bali Prasad, Meenakshi Singh, Anil Kumar, Sandhya SinghAbstract:The Electrolytic Conductivity of crystal violet-based quaternary ammonium polyelectrolytes in very dilute solutions of propylene carbonate at 25 o C and sulfolane at 30 o C has been measured. It was not possible to determine the limiting molar Conductivity, Λ 0 , from the nonlinear electrolyte Conductivity, κ, against concentration curves for the systems studied. An empirical approach based on the Lattey equation has been used to determine limiting mobilities of polycations. A modest correlation has been made with the counterion condensation and polycation conformations in order to explain the relative magnitude of limiting molar conductivities
Meenakshi Singh - One of the best experts on this subject based on the ideXlab platform.
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Electrolytic Conductivity of crystal violet based quaternary ammonium polyelectrolytes in N,N′-dimethylformamide and dimethyl sulfoxide
Canadian Journal of Chemistry, 1997Co-Authors: Meenakshi Singh, Anil Kumar, Shirley Easo, Bhim Bali PrasadAbstract:Electrolytic conductivities of crystal violet based quaternary ammonium polyelectrolytes in very dilute solutions of dimethylformamide and dimethyl sulfoxide at 25 °C have been investigated. The Electrolytic Conductivity (κ) as a function of concentration for systems having a reduced charge density (ξ) greater than unity revealed a very narrow range of linearity in the dilute region. A modest correlation has been made with the counterion condensation and the polycation conformations in order to explain the relative magnitude of limiting equivalent conductivities. Keywords: conductance, polyelectrolyte, aprotic solvent, solvation, counterion condensation.
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Electrolytic Conductivity of the N-Chloranil- and N-Xylylene-Based Polyelectrolytes in Dimethylformamide and Dimethyl Sulfoxide
Journal of Chemical & Engineering Data, 1996Co-Authors: Meenakshi Singh, Bhim Bali PrasadAbstract:Electrolytic conductivities of four typical nitrogen-based polycations, where quaternary nitrogens in the molecular chain are attached with chloranil and xylylene moieties and are interspersed with ethylene, phenothiazine, and bipyridyl (viologen), linkages, have been investigated in dimethylformamide and dimethyl sulfoxide at 25 °C. The Electrolytic Conductivity as a function of concentration for systems with high charge density revealed a very narrow range of linearity in the dilute region. An empirical approach based on the Lattey equation is found suitable for the determination of the limiting mobilities of the polyions.
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Electrolytic Conductivity of Crystal Violet-Based Quaternary Ammonium Polyelectrolytes in Propylene Carbonate and Sulfolane
Journal of Chemical & Engineering Data, 1995Co-Authors: Bhim Bali Prasad, Meenakshi Singh, Anil Kumar, Sandhya SinghAbstract:The Electrolytic Conductivity of crystal violet-based quaternary ammonium polyelectrolytes in very dilute solutions of propylene carbonate at 25 o C and sulfolane at 30 o C has been measured. It was not possible to determine the limiting molar Conductivity, Λ 0 , from the nonlinear electrolyte Conductivity, κ, against concentration curves for the systems studied. An empirical approach based on the Lattey equation has been used to determine limiting mobilities of polycations. A modest correlation has been made with the counterion condensation and polycation conformations in order to explain the relative magnitude of limiting molar conductivities
Sandhya Singh - One of the best experts on this subject based on the ideXlab platform.
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Electrolytic Conductivity of Crystal Violet-Based Quaternary Ammonium Polyelectrolytes in Propylene Carbonate and Sulfolane
Journal of Chemical & Engineering Data, 1995Co-Authors: Bhim Bali Prasad, Meenakshi Singh, Anil Kumar, Sandhya SinghAbstract:The Electrolytic Conductivity of crystal violet-based quaternary ammonium polyelectrolytes in very dilute solutions of propylene carbonate at 25 o C and sulfolane at 30 o C has been measured. It was not possible to determine the limiting molar Conductivity, Λ 0 , from the nonlinear electrolyte Conductivity, κ, against concentration curves for the systems studied. An empirical approach based on the Lattey equation has been used to determine limiting mobilities of polycations. A modest correlation has been made with the counterion condensation and polycation conformations in order to explain the relative magnitude of limiting molar conductivities
Hans Jensen - One of the best experts on this subject based on the ideXlab platform.
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Bridging the Gap Between Ultrapure Water and Reference Materials in Electrolytic Conductivity Measurements
IEEE Transactions on Instrumentation and Measurement, 2017Co-Authors: Carsten Thirstrup, Alan Snedden, Hans JensenAbstract:This paper reports a closed-flow-loop Electrolytic Conductivity measurement system enabling calibration of Conductivity sensors from the Conductivity level of ultrapure water (UPW) at $5.5~\mu \text{S}$ /m up till the range of 10 to 140 mS/m, where stable certified reference materials (CRMs) for Conductivity are available. The system is traceable to the SI unit system. A comparison made with another Electrolytic Conductivity measurement system, which is based on Jones-type Conductivity cells designed to be used primarily for conductivities larger than ~10 mS/m, shows an agreement better than 0.1%. The most commonly used calibration method of Conductivity sensors is based on CRMs and the extrapolation of the data to low Conductivity values ( $ /m). In contrast, the present closed-flow-loop Electrolytic Conductivity measurement system is based on the measurements made at Conductivity levels where the sensor is used; it is, therefore, a better alternative.
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Electrolytic Conductivity as a Quality Indicator for Bioethanol
ACTA IMEKO, 2014Co-Authors: Steffen Seitz, Petra Spitzer, Hans Jensen, E. Orrù, F. DurbianoAbstract:We present results of the European Metrology Research Project on the SI traceability of Electrolytic Conductivity measurements in bioethanol. As a first step to this aim secondary Conductivity measurements have been performed to characterize reproducibility, stability, measurement uncertainty and the significance of the measurement results. The relative standard measurement uncertainty is of the order 0.3%, while inter-laboratory reproducibility is around 6.9%. The measured conductivities of two samples from different sources show a relative difference of around 30%. These results show that Conductivity is an appropriate quality indicator for bioethanol. However, it also demonstrates that inter-laboratory reproducibility has to be improved, in particular with respect to SI traceability.
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traceability of Electrolytic Conductivity measurements to the international system of units in the sub ms m 1 region and review of models of Electrolytic Conductivity cells
Electrochimica Acta, 2010Co-Authors: Steffen Seitz, Pia Tønnes Jakobsen, Hans Jensen, Alessandra Manzin, Petra SpitzerAbstract:Abstract The present paper focuses on the currently available reliability of the results of Electrolytic Conductivity measurements in the low Conductivity range, emphasizing its weaknesses with respect to SI traceability. Electrochemical and physical effects at the electrode–solution interface influencing the measured impedance spectra are outlined, giving an overview of models that can be employed to investigate the frequency response of Electrolytic Conductivity cells to an applied AC voltage. Particular attention is devoted to the determination of the bulk resistance of the solution, which is necessary to derive the Electrolytic Conductivity of aqueous solutions traceable to the SI in the sub mS m −1 range.
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Traceability of Electrolytic Conductivity measurements to the International System of Units in the sub mS m−1 region and review of models of Electrolytic Conductivity cells
Electrochimica Acta, 2010Co-Authors: Steffen Seitz, Pia Tønnes Jakobsen, Hans Jensen, Alessandra Manzin, Petra SpitzerAbstract:Abstract The present paper focuses on the currently available reliability of the results of Electrolytic Conductivity measurements in the low Conductivity range, emphasizing its weaknesses with respect to SI traceability. Electrochemical and physical effects at the electrode–solution interface influencing the measured impedance spectra are outlined, giving an overview of models that can be employed to investigate the frequency response of Electrolytic Conductivity cells to an applied AC voltage. Particular attention is devoted to the determination of the bulk resistance of the solution, which is necessary to derive the Electrolytic Conductivity of aqueous solutions traceable to the SI in the sub mS m −1 range.
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Metrological Traceability Concept for Electrolytic Conductivity and pH
CHIMIA International Journal for Chemistry, 2009Co-Authors: Steffen Seitz, Petra Spitzer, Pia Tønnes Jakobsen, Hans JensenAbstract:The metrological traceability concept links measurement results by a chain of calibrations to the quantity values of primary standards, which are realised by primary measurement procedures. These procedures undergo periodical international comparison measurements, in order to guarantee worldwide comparability of measurement results. In this article we demonstrate how the metrological traceability concept applies to Electrolytic Conductivity and pH measurements. Furthermore we will outline promising activities in current metrological research to extend traceability of Electrolytic Conductivity measurements down to the low μS cm -1 level.
Petra Spitzer - One of the best experts on this subject based on the ideXlab platform.
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Electrolytic Conductivity as a Quality Indicator for Bioethanol
ACTA IMEKO, 2014Co-Authors: Steffen Seitz, Petra Spitzer, Hans Jensen, E. Orrù, F. DurbianoAbstract:We present results of the European Metrology Research Project on the SI traceability of Electrolytic Conductivity measurements in bioethanol. As a first step to this aim secondary Conductivity measurements have been performed to characterize reproducibility, stability, measurement uncertainty and the significance of the measurement results. The relative standard measurement uncertainty is of the order 0.3%, while inter-laboratory reproducibility is around 6.9%. The measured conductivities of two samples from different sources show a relative difference of around 30%. These results show that Conductivity is an appropriate quality indicator for bioethanol. However, it also demonstrates that inter-laboratory reproducibility has to be improved, in particular with respect to SI traceability.
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traceability of Electrolytic Conductivity measurements to the international system of units in the sub ms m 1 region and review of models of Electrolytic Conductivity cells
Electrochimica Acta, 2010Co-Authors: Steffen Seitz, Pia Tønnes Jakobsen, Hans Jensen, Alessandra Manzin, Petra SpitzerAbstract:Abstract The present paper focuses on the currently available reliability of the results of Electrolytic Conductivity measurements in the low Conductivity range, emphasizing its weaknesses with respect to SI traceability. Electrochemical and physical effects at the electrode–solution interface influencing the measured impedance spectra are outlined, giving an overview of models that can be employed to investigate the frequency response of Electrolytic Conductivity cells to an applied AC voltage. Particular attention is devoted to the determination of the bulk resistance of the solution, which is necessary to derive the Electrolytic Conductivity of aqueous solutions traceable to the SI in the sub mS m −1 range.
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Traceability of Electrolytic Conductivity measurements to the International System of Units in the sub mS m−1 region and review of models of Electrolytic Conductivity cells
Electrochimica Acta, 2010Co-Authors: Steffen Seitz, Pia Tønnes Jakobsen, Hans Jensen, Alessandra Manzin, Petra SpitzerAbstract:Abstract The present paper focuses on the currently available reliability of the results of Electrolytic Conductivity measurements in the low Conductivity range, emphasizing its weaknesses with respect to SI traceability. Electrochemical and physical effects at the electrode–solution interface influencing the measured impedance spectra are outlined, giving an overview of models that can be employed to investigate the frequency response of Electrolytic Conductivity cells to an applied AC voltage. Particular attention is devoted to the determination of the bulk resistance of the solution, which is necessary to derive the Electrolytic Conductivity of aqueous solutions traceable to the SI in the sub mS m −1 range.
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Metrological Traceability Concept for Electrolytic Conductivity and pH
CHIMIA International Journal for Chemistry, 2009Co-Authors: Steffen Seitz, Petra Spitzer, Pia Tønnes Jakobsen, Hans JensenAbstract:The metrological traceability concept links measurement results by a chain of calibrations to the quantity values of primary standards, which are realised by primary measurement procedures. These procedures undergo periodical international comparison measurements, in order to guarantee worldwide comparability of measurement results. In this article we demonstrate how the metrological traceability concept applies to Electrolytic Conductivity and pH measurements. Furthermore we will outline promising activities in current metrological research to extend traceability of Electrolytic Conductivity measurements down to the low μS cm -1 level.
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pH and Electrolytic Conductivity as parameters to characterize bioethanol
Accreditation and Quality Assurance, 2009Co-Authors: Petra Spitzer, Steffen Seitz, Paola Fisicaro, Rachel ChampionAbstract:To guarantee the quality of bioethanol and avoid damage to the fuel system in a car, the determination of acidity, water content, as well as chloride, sulfate, alkali metal and alkaline earth metal content are important. Electrochemical quantities like pH and Electrolytic Conductivity are frequently used in biofuel analysis as sum parameters mainly to indicate the risk of corrosion. Many standards and measurement methods used today in the analysis of biofuel are adopted from specifications and test methods originally developed for fossil-based fuels and commercial alcohol. This results from the rapid expansion of the biofuel production. There are efforts to solve remaining metrological and regulatory issues on a regional and international basis on a short term. In the following an overview on the fundamentals for the measurement of pH in bioethanol blends is given. It will be discussed if the Electrolytic Conductivity of the bioethanol could be a reliable measure of corrosion causing ionic contaminations in biofuel. State of the art, limitations and future tasks for metrology will be discussed.