Dielectric permittivity and relaxation in aqueous solutions of alkali metal sulfates and nitrates in the temperature range 288–313 K

Лилеев, А. С.; Филимонова, З. А.; Lyashchenko, A. K.

doi:10.1016/s0167-7322(02)00148-4

Cited by 33 publications

(14 citation statements)

References 5 publications

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“…In this test, the introduction of nitrate-nitrogen dissolved as nitrate ion, which decrease the dielectric constant of the media. This result is in agreement with the study conducted by Lileev et al (2003), since they found the values of dielectric constant of the solution containing nitrate ion decreased with the increase of salt concentration. Figure 5 showed the sensor output for different batches as well as the profiles of different nitrogen along with the increasing moisture content treated by ammonium-hydroxide enriching.…”

Section: Influence Of Different Nitrogen Loadingsupporting

confidence: 93%

Monitoring moisture content of gas-phase biofilter based on impedance under different conditions

Zheng

Yang

Wang

2016

2016 ASABE International Meeting

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The woodchips-based gas phase biofilter is capable of mitigating airborne ammonia efficiently. The ability to monitor real-time moisture content of biofilter media is preferred for maintaining the ammonia mitigation efficiency. The focus of this study is to enhance the understanding of impedance-based moisture content measurement and improve methodologies to monitor the moisture content of gas phase ammonia mitigation biofilters more accurately. A proposed sensor consisting of a sensing unit (three parallel plates) and a circuit generating DC voltage outputs was used in the study. The sensor readings changed with step-wise increase of moisture content as well as different particle size distribution and nitrogen (ammonia-nitrogen, nitrate-nitrogen) concentrations of biofilter media. The results showed the particle size distribution and nitrogen concentrations have significant impacts on impedance-based moisture sensing. A mathematical model was established to correlate the sensor reading of the impedance-based moisture sensor with moisture content, ammonia-nitrogen concentration, and nitrate-nitrogen concentration based on experimental results. Further studies are needed to improve the performance of the sensor considering other potential factors.

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Section: Influence Of Different Nitrogen Loadingsupporting

confidence: 93%

Monitoring moisture content of gas-phase biofilter based on impedance under different conditions

Zheng

Yang

Wang

2016

2016 ASABE International Meeting

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“…In this test, the introduction of nitrate-nitrogen reduced to nitrate ions, which decreased the dielectric constant of the media. This result is consistent with the study carried out by Lileev et al (2003), who found that the values of the dielec-tric constant of a solution containing nitrate ions decreased with the increase in salt concentration, and the stronger the ion hydration, the less the dielectric constant.…”

Section: Sensor Response To Nitrogen Concentration With Changing Moissupporting

confidence: 93%

Impedance-Based Moisture Content Sensor Assessment for Gas-Phase Biofilter Media

Zhao

Yang

Gates

et al. 2017

Transactions of the ASABE

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Abstract. A woodchip-based gas-phase biofilter is capable of mitigating livestock airborne ammonia efficiently with low cost. Control of the moisture content (MC) of biofilter media is critical for ammonia mitigation and limiting nitrous oxide generation. It is important to monitor the real-time biofilter MC to maintain biofilter performance. The objectives of this study were to further develop and evaluate impedance-based MC measurement and to improve methodologies to monitor the MC of gas-phase biofilters. A sensor consisting of a sensing unit (three perforated parallel plates) and a circuit generating DC voltage output was used to measure MC. The sensor readings changed significantly with stepwise MC increases, particle size distribution, and nitrogen (ammonia-nitrogen, nitrate-nitrogen) concentrations in biofilter media. A mathematical model was developed for the relationship between the sensor reading and MC. A statistical model was established to predict the MC in biofilter media based on the sensor reading, ammonia-nitrogen concentration, and nitrate-nitrogen concentration. Keywords: Gas-phase biofilter, Impedance, Moisture sensor, Nitrogen compounds, Particle size distribution.

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“…Likewise, dielectric properties of A c c e p t e d M a n u s c r i p t nitrate-based aqueous solutions have been reported within the same concentration range in [12] and extended to higher concentrations up to 8.54 mol/L in [13]. Dielectric spectra of sulphate-based ions have also been studied for a moderate concentration range, from 0.05 mol/L to 3 mol/L [13,14]. The existing studies of dielectric properties of aqueous solutions, however, have been limited by the lack of available data in the literature for very low, agriculturally-relevant concentration levels.…”

Section: -mentioning

confidence: 80%

“…The Jacobian matrix comprises the first-order partial derivatives of the fitting equation ŷ(xi, a1, …, am) with respect to the fitting parameters a1, …, am. In order to include the uncertainties associated with the measured data uc(xi) in obtaining the uncertainties of the fitting parameters, the Jacobian matrix and the mean squared error are weighted as in equations (12) and (13), respectively. , , , )…”

Section: Covariance Matrix Methodsmentioning

confidence: 99%

Dielectric measurement of low-concentration aqueous solutions: assessment of uncertainty and ion-specific responses

Gorji

Bowler

2018

Meas. Sci. Technol.

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Excessive amounts of chemicals and ions flowing into water sources cause serious environmental and humanhealth related concerns. The lack of affordable and real-time monitoring systems for these contaminants limits effective conservation and management strategies. To establish a basis for developing an effective, fast, realtime, and affordable sensing system, dielectric spectroscopy method has been employed to characterize aqueous solutions of sodium chloride (NaCl), sodium nitrate (NaNO3), and sodium sulphate (Na2SO4) at environmentally-relevant (low) concentrations. Dielectric spectra were measured over the frequency range from 200 MHz to 20 GHz, at temperature 25 ± 0.01 °C and for concentrations 0 to 20 mmol/L. The measured spectra were fitted with a Debye model using a non-linear, weighted, least-squares analysis. A method of judiciously exploiting the resulting fitting parameters is proposed, that allows the concentration and type of ions to be uniquely determined. Uncertainties due to random and systematic errors that contribute to the measured dielectric spectra and become critical in the context of low concentration aqueous solutions have been assessed. Furthermore, two methods of calculating associated uncertainties of the indicator parameters, viz. covariance matrix and Monte Carlo methods have been performed. The results show the numerical approach taken by Monte Carlo method, while yielding the same estimates, reduces the tediousness accompanied by analytical covariance matrix method.

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Dielectric permittivity and relaxation in aqueous solutions of alkali metal sulfates and nitrates in the temperature range 288–313 K

Cited by 33 publications

References 5 publications

Monitoring moisture content of gas-phase biofilter based on impedance under different conditions

Monitoring moisture content of gas-phase biofilter based on impedance under different conditions

Impedance-Based Moisture Content Sensor Assessment for Gas-Phase Biofilter Media

Dielectric measurement of low-concentration aqueous solutions: assessment of uncertainty and ion-specific responses

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