scholarly journals Open-Ended Coaxial Probe Measurements of Complex Dielectric Permittivity in Diesel-Contaminated Soil during Bioremediation

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6677
Author(s):  
Andrea Vergnano ◽  
Alberto Godio ◽  
Carla Maria Raffa ◽  
Fulvia Chiampo ◽  
Jorge A. Tobon Vasquez ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Moisture Content ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Complex Dielectric Permittivity ◽  
Imaginary Component ◽  
Real Component ◽  
The Real ◽  
Coaxial Probe

In the bioremediation field, geophysical techniques are commonly applied, at lab scale and field scale, to perform the characterization and the monitoring of contaminated soils. We propose a method for detecting the dielectric properties of contaminated soil during a process of bioremediation. An open-ended coaxial probe measured the complex dielectric permittivity (between 0.2 and 20 GHz) on a series of six soil microcosms contaminated by diesel oil (13.5% Voil/Vtot). The microcosms had different moisture content (13%, 19%, and 24% Vw/Vtot) and different salinity due to the addition of nutrients (22 and 15 g/L). The real and the imaginary component of the complex dielectric permittivity were evaluated at the initial stage of contamination and after 130 days. In almost all microcosms, the real component showed a significant decrease (up to 2 units) at all frequencies. The results revealed that the changes in the real part of the dielectric permittivity are related to the amount of degradation and loss in moisture content. The imaginary component, mainly linked to the electrical conductivity of the soil, shows a significant drop to almost 0 at low frequencies. This could be explained by a salt depletion during bioremediation. Despite a moderate accuracy reduction compared to measurements performed on liquid media, this technology can be successfully applied to granular materials such as soil. The open-ended coaxial probe is a promising instrument to check the dielectric properties of soil to characterize or monitor a bioremediation process.

Effect of compost in phytoremediation of diesel-contaminated soils

2001 ◽  
Vol 43 (2) ◽  
pp. 291-295 ◽  
Author(s):  
J. Vouillamoz ◽  
M. W. Milke
Keyword(s):  
Moisture Content ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Petroleum Hydrocarbons ◽  
Dilution Effect ◽  
Screening Tests ◽  
Total Petroleum Hydrocarbons ◽  
Controlled Environment ◽  
Grass Growth ◽  
The Impact

The effect of compost on phytoremediation of diesel-contaminated soils was investigated using 130 small (200 g) containers in two screening tests. The experiments were conducted in a controlled environment using ryegrass from seed. Containers were destructively sampled at various times and analyzed for plant mass and total petroleum hydrocarbons. The results indicate that the presence of diesel reduces grass growth, and that compost helps reduced the impact of diesel on grass growth. The addition of compost helps increase diesel loss from the soils both with and without grass, though the addition of grass leads to lower diesel levels compared with controls. A second set of experiments indicates that the compost helps in phytoremediation of diesel-contaminated soil independent of the dilution effect that compost addition has. The results indicate that the compost addition allowed diesel loss down to 200 mg TPH/kg even though the compost would be expected to hold the diesel more tightly in the soil/compost mixture. The simplicity of the screening tests led to difficulties in controlling moisture content and germination rates. The conclusion of the research is that the tilling of compost into soils combined with grass seeding appears to be a valuable option for treating petroleum-contaminated soils.

The Absorption and Reflection of Microwave Radiation by a Mercury-Vapour Discharge

1952 ◽  
Vol 5 (4) ◽  
pp. 592
Author(s):  
HA Prime
Keyword(s):  
Discharge Current ◽  
Power Transmission ◽  
Imaginary Component ◽  
Mercury Vapour ◽  
Ionized Gas ◽  
Real Component ◽  
The Real ◽  
Transmission And Reflection Coefficients ◽  
Rate Of Increase ◽  
Transmission And Reflection

The power transmission and reflection coefficients of a limited volume of ionized gas (a mercury-vapour discharge) located within a waveguide have been measured at a frequency of approximately 10,000 Mc/s. by a microwave method. From these coefficients the real and imaginary components of the complex conductivity of the discharge are evaluated. The results show that the real component of the conductivity бr is a linearly increasing function of the discharge current, whereas the rate of increase of the imaginary component бi, which is negative, decreases with increasing discharge current. The ratio бi/бr, decreases with increase in current, but is of the order of unit;- due to the fact that the gas pressure is sufficiently high (?1 atm.) to make бr comparable with бi. The theoretical basis of the work is presented in an appendix in which the particular case of high pressure conditions is discussed.

scholarly journals Development of a Resonant Microwave Sensor for Sediment Density Characterization

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1058 ◽  
Author(s):  
R. Mansour ◽  
S. Rioual ◽  
B. Lescop ◽  
P. Talbot ◽  
M. Abboud ◽  
...  
Keyword(s):  
Dielectric Permittivity ◽  
Water Content ◽  
Printed Circuit Board ◽  
Ionic Species ◽  
Bulk Water ◽  
Circuit Board ◽  
Complex Dielectric Permittivity ◽  
Polarization Sensitivity ◽  
Electrode Polarization ◽  
The Real

In this study, a sensor based on the development of a planar antenna immersed in sediments dedicated to water content monitoring in this type of material is proposed and experimentally validated. It is produced by a conventional Printed Circuit Board (PCB) manufacturing process on a double-sided metalized FR4 substrate. The sensitivity of the sensor is ensured by the variation of the real part of the complex dielectric permittivity of sediments with water content at around 1 GHz. As shown, in this frequency range, electrode polarization and Maxwell–Wagner polarization effects become negligible, leading to only a bulk water polarization sensitivity. The sensor operates in the reflection mode by monitoring the variation of the resonant frequency as a function of the sediment density through the S11 reflection measurements. An experimental sensitivity of 820   MHz . g − 1 . cm 3 was achieved. Despite the simplification of data interpretation at the considered frequency, the influence of ionic species such as NaCl in sediments on the real part of the relative complex dielectric permittivity is highlighted. This demonstrates the importance of considering a second parameter such as the S11 level at low frequency or the electrical conductivity to extract the density from the frequency measurements.

scholarly journals A Seven-Rod Dielectric Sensor for Determination of Soil Moisture in Well-Defined Sample Volumes

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1646 ◽  
Author(s):  
Justyna Szerement ◽  
Aleksandra Woszczyk ◽  
Agnieszka Szypłowska ◽  
Marcin Kafarski ◽  
Arkadiusz Lewandowski ◽  
...  
Keyword(s):  
Dielectric Permittivity ◽  
Water Content ◽  
Sandy Loam ◽  
Sample Volume ◽  
Time Domain Reflectometry ◽  
Complex Dielectric Permittivity ◽  
The Real ◽  
Electromagnetic Simulations ◽  
Different Diameters ◽  
Permittivity Spectrum

This paper presents a novel seven-rod sensor used for time-domain reflectometry (TDR) and frequency-domain reflectometry (FDR) measurements of soil water content in a well-defined sample volume. The probe directly measures the complex dielectric permittivity spectrum and for this purpose requires three calibration media: air, water, and ethanol. Firstly, electromagnetic simulations were used to study the influence of the diameter of a container on the sensitivity zone of the probe with respect to the measured calibration media and isopropanol as a verification liquid. Next, the probe was tested in three soils—sandy loam and two silt loams—with six water contents from air-dry to saturation. The conversion from S 11 parameters to complex dielectric permittivity from vector network analyzer (VNA) measurements was obtained using an open-ended liquid procedure. The simulation and measurement results for the real part of the isopropanol dielectric permittivity obtained from four containers with different diameters were in good agreement with literature data up to 200 MHz. The real part of the dielectric permittivity was extracted and related to the moisture of the tested soil samples. Relations between the volumetric water content and the real part of the dielectric permittivity (by FDR) and apparent dielectric permittivity (by TDR) were compared with Topp’s equation. It was concluded that the best fit to Topp’s equation was observed in the case of a sandy loam. Data calculated according to the equation proposed by Malicki, Plagge, and Roth gave results closer to Topp’s calibration. The obtained results indicated that the seven-rod probe can be used to accurately measure of the dielectric permittivity spectrum in a well-defined sample volume of about 8 cm3 in the frequency range from 20 MHz to 200 MHz.

Toxicity Assessment of some Crude Oil Contaminated Soils in the Niger Delta

2009 ◽  
Vol 62-64 ◽  
pp. 451-455 ◽  
Author(s):  
F.A. Aisien ◽  
J.C. Chiadikobi ◽  
E.T. Aisien
Keyword(s):  
Heavy Metals ◽  
Moisture Content ◽  
Crude Oil ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Niger Delta ◽  
Extraction Methods ◽  
Toxicity Assessment ◽  
Soil Samples ◽  
Physiochemical Parameters

This paper considered the toxicity assessment of some crude oil contaminated soils in Niger Delta areas. The soil samples were collected from different horizontal distances, vertical depths and contaminated soil of different ages. The heavy metals in the contaminated soils were digested and extracted using di-acid digested and DTPA extraction methods respectively. The physiochemical parameters (moisture content, pH, N, P and heavy metals (Ni, Pb and Cd) were analysed with APHA method. The heavy metals concentration was determined using atomic absorption spectrophotometer (AAS). The results show that the metals concentration decreased with the age of the contaminated soil and with increased vertical depths. However, the metals concentrations were almost constant at different horizontal distances. Similar trend was observed for the moisture content, pH, N, P and K.

scholarly journals Dielectric properties of Bi12SiO20 crystals doped with Al

2019 ◽  
Vol 27 (2) ◽  
pp. 85-88
Author(s):  
T. V. Panchenko ◽  
L. M. Karpova
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Electric Field ◽  
Hysteresis Loops ◽  
Complex Dielectric Permittivity ◽  
Temperature Range ◽  
Dielectric Matrix ◽  
Before And After ◽  
Frequency Dependences

The temperature-frequency dependences of the complex dielectric permittivity ε and the voltage-farad characteristics of undoped and aluminum doped Bi12SiO20 crystals are studied before and after their polarization. It is shown that Al ions in the Bi12SiO20 dielectric matrix provide a significant increase as well as nonlinearity of ε in the temperature range 300 – 800 K and electric field strengths Е = 103 – 104 V/cm. It is shown that polarization causes the appearance of dielectric hysteresis loops. Al impurity significantly affects the appearance and parameters of these loops. The role of Al ions in increasing the contribution of the quasi-dipole mechanism in the polarization processes is revealed.

scholarly journals Space–Time Spectral Analysis of the Moist Static Energy Budget Equation

2018 ◽  
Vol 32 (2) ◽  
pp. 501-529 ◽  
Author(s):  
Kazuaki Yasunaga ◽  
Satoru Yokoi ◽  
Kuniaki Inoue ◽  
Brian E. Mapes
Keyword(s):  
Positive Real Part ◽  
Radiative Heating ◽  
Imaginary Component ◽  
Moist Static Energy ◽  
Coherent Signals ◽  
Positive Real ◽  
Real Component ◽  
The Real ◽  
Budget Equation ◽  
Static Energy

Abstract The budget of column-integrated moist static energy (MSE) is examined in wavenumber–frequency transforms of longitude–time sections over the tropical belt. Cross-spectra with satellite-derived precipitation (TRMM-3B42) are used to emphasize precipitation-coherent signals in reanalysis [ERA-Interim (ERAI)] estimates of each term in the budget equation. Results reveal different budget balances in convectively coupled equatorial waves (CCEWs) as well as in the Madden–Julian oscillation (MJO) and tropical depression (TD)-type disturbances. The real component (expressing amplification or damping of amplitude) for horizontal advection is modest for most wave types but substantially damps the MJO. Its imaginary component is hugely positive (it acts to advance phase) in TD-type disturbances and is positive for MJO and equatorial Rossby (ERn1) wave disturbances (almost negligible for the other CCEWs). The real component of vertical advection is negatively correlated (damping effect) with precipitation with a magnitude of approximately 10% of total latent heat release for all disturbances except for TD-type disturbance. This effect is overestimated by a factor of 2 or more if advection is computed using the time–zonal mean MSE, suggesting that nonlinear correlations between ascent and humidity would be positive (amplification effect). ERAI-estimated radiative heating has a positive real part, reinforcing precipitation-correlated MSE excursions. The magnitude is up to 14% of latent heating for the MJO and much less for other waves. ERAI-estimated surface flux has a small effect but acts to amplify MJO and ERn1 waves. The imaginary component of budget residuals is large and systematically positive, suggesting that the reanalysis model’s physical MSE sources would not act to propagate the precipitation-associated MSE anomalies properly.

Dielectric Permittivity of Polymers Containing Conductive Inclusions

1990 ◽  
Vol 214 ◽  
Author(s):  
A.N. Kolesnicov ◽  
A.N. Lagar'kov ◽  
S.M. Matitsin ◽  
L.N. Novogrudskiy ◽  
K.N. Rozanov ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Frequency Dispersion ◽  
Point Of View ◽  
Microwave Properties ◽  
Complex Dielectric Permittivity ◽  
Filled Polymers ◽  
Physical Point ◽  
Effective Dielectric Permittivity

Filled polymers containing conductive inclusions possess a number of unique microwave properties. The effective values of real ε1 and imaginary ε2 parts of complex dielectric permittivity ε=ε1 + εz of these materials may be easily changed by variation of their composition. The values of ε1 may have high (up to several hundreds) as well as negative meanings [1]. Besides, the filled polymers containing conductive inclusions may possess strong frequency dispersion of the effective dielectric permittivity at wavelengths λ∼1, where 1 is a size of inclusion. The investigation of dielectric properties of these materials at microwaves is of great interest as from the physical point of view as for technical applications.

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