Microwave Determination of Water Mole Fraction in Humid Gas Mixtures

Cuccaro, R.; Gavioso, R. M.; Benedetto, G.; Ripa, D. Madonna; Fernicola, Vito; Guianvarc'H, Cécile

doi:10.1007/s10765-011-1007-x

Cited by 20 publications

(18 citation statements)

References 23 publications

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“…The system simultaneously measures scattering parameters of the transmitted and reflected waves in the Q- frequency band (30 GHz to 50 GHz) centered at 40 GHz. The real part of the relative dielectric permittivity of air in the Q-band is approximately ε r ' ≈ 1.00058 [39]–[41]. This corresponds to a wavelength λ 0 ≈ 7.493 mm at the center frequency of 40 GHz.…”

Section: Resultsmentioning

confidence: 99%

“…At these nominal conditions the amount of water in air is about 8.6 g/m 3 of air or 1.45×10 −2 mole fraction ( mol H 2 O / mol air ). The corresponding relative dielectric constant of humid air ε r ' = 1.000580 [39]. We note that in the definition of the matrices Q air we neglected the real part of the propagation constant, α, which represents the attenuation due to the dielectric loss from the moisture in humid air.…”

Section: Uncertainty Analysismentioning

confidence: 99%

“…From the data in [39] we find that at RH of 75 % the mole fraction of water increases to about 1.7×10 −2 , yet the change in ε r ' is not significant, ε r ' ≈ 1.000582. The attenuation coefficient at 35 GHz, increases from 6×10 −5 dB/m to 1.5×10 −4 dB/m [40].…”

Section: Uncertainty Analysismentioning

confidence: 99%

“…Thus, the possible variations in temperature and humidity in the lab environment can lead to uncertainties in the order of ± 10 −5 dB in the magnitude of the measured scattering parameters which can be neglected with respect to the other uncertainties quantified in Table 1. Regarding the phase constant in air, references [39]–[41] show that in the Q-band frequency range, the phase constant for air varies slightly with temperature and humidity, between 1.00025 ω/ c 0 and 1.00035 ω/ c 0 . This leads to an uncertainty of 0.0001 ω/ c 0 × (225×10 −3 m) radians in the phase of the scattering parameters which corresponds to a maximum uncertainty of 0.0236 radians or 1.35° in the phase of the measured scattering parameters at the frequency of 50 GHz.…”

Section: Uncertainty Analysismentioning

confidence: 99%

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A $Q$ -Band Free-Space Characterization of Carbon Nanotube Composites

Hassan

Obrzut

Garboczi

2016

IEEE Trans. Microwave Theory Techn.

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We present a free-space measurement technique for non-destructive non-contact electrical and dielectric characterization of nano-carbon composites in the Q-band frequency range of 30 GHz to 50 GHz. The experimental system and error correction model accurately reconstruct the conductivity of composite materials that are either thicker than the wave penetration depth, and therefore exhibit negligible microwave transmission (less than −40 dB), or thinner than the wave penetration depth and, therefore, exhibit significant microwave transmission. This error correction model implements a fixed wave propagation distance between antennas and corrects the complex scattering parameters of the specimen from two references, an air slab having geometrical propagation length equal to that of the specimen under test, and a metallic conductor, such as an aluminum plate. Experimental results were validated by reconstructing the relative dielectric permittivity of known dielectric materials and then used to determine the conductivity of nano-carbon composite laminates. This error correction model can simplify routine characterization of thin conducting laminates to just one measurement of scattering parameters, making the method attractive for research, development, and for quality control in the manufacturing environment.

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Section: Resultsmentioning

confidence: 99%

Section: Uncertainty Analysismentioning

confidence: 99%

Section: Uncertainty Analysismentioning

confidence: 99%

Section: Uncertainty Analysismentioning

confidence: 99%

See 2 more Smart Citations

A $Q$ -Band Free-Space Characterization of Carbon Nanotube Composites

Hassan

Obrzut

Garboczi

2016

IEEE Trans. Microwave Theory Techn.

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“…To obtain focused dimensional targeting the laser is lead through a specially designed optic fiber, which allows also to collect the diffused reflected light. This makes it unique compared to other moisture sensing techniques [5,6,7,8].…”

Section: Introductionmentioning

confidence: 99%

Industrial Implementation of the New Nir Laser-Based Sensor for Measuring Surface Moisture in Polymers

Hudoklin

Lopez

Beges

et al. 2015

17th International Congress of Metrology

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Mise en oeuvre industrielle d'un nouveau capteur, utilisant le proche infra-rouge laser, pour mesurer l'humidité en surface des polymères Hudoklin D 1,a Abstract. In special applications, such as the transient adhesion process over small polymer components used in electric motors, electronic circuit coating or moisture transport in wood; moisture in the upper layers, close to the surface and at the surface, affects the processes more rapidly. Existing measuring principles, such as those based on nuclear magnetic resonance, are cumbersome to use and they are also less suitable for some parts of the moisture range. For this reason, a novel, non-contact, light-reflection type of moisture sensor was investigated, designed and developed (patent pending). It is based on a water molecule's light-absorbing characteristics in the near-infrared (NIR) spectrum. The light from a double laser diode is led through an optical fiber and reflected back from a sample to an InGaAs photodiode detector. The high stability of the relatively low-cost laser source was achieved through a constant-power laser-control circuit. The sensor was designed for measuring the surface and near-surface moisture on a polymer samples with complex geometry and thin walls, which proved to achieve an approximately 0.1% of effective resolution of bulk moisture content below 2 %. The tests showed that the mechanical set-up of the samples plays a significant role. For this reason the special measuring cell was designed in order to be able to use the sensor in an industrial process line, where every year several hundred thousands of polymer samples are manufactured. The advancements from first introduction of the sensor will be presented, together with the experience obtained with its industrial implementation. The later work is in close relation with the activities of the European metrology research programme (EMRP) joint research project Metefnet.

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Measuring Humidity in Methane and Natural Gas with a Microwave Technique

et al. 2014

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The results of microwave measurements with a quasi-spherical resonator in\ud humid methane samples realized under laboratory conditions at the Istituto Nazionale\ud di Ricerca Metrologica (INRiM) and under industrial conditions in a natural gas sample\ud made available at the facilities of the Technical Manager of the Spanish Gas System\ud and main supplier of natural gas in Spain (ENAGAS) are reported. Measurements at\ud INRiM included vapor phase and condensation tests on methane samples prepared with\ud amount fractions of water between 600ppm and 5000ppm at temperatures between\ud 273K and 295K and pressures between 150kPa and 1MPa. ENAGAS measurements\ud were performed at ambient temperature, 750kPa on natural gas sampled from the\ud pipeline and successively humidified at amount fractions of water between 140ppm\ud and 250ppm for completeness of the comparison with several humidity sensors and\ud instrumentation based on different technologies. To enhance the sensitivity of the\ud microwave method at low humidity, an experimental procedure based on the relative\ud comparison of the dielectric permittivity of the humid gas sample before and after being subject to a chemical drying process was conceived and implemented. The\ud uncertainty budget and the final sensitivity of this procedure are discussed

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Microwave Determination of Water Mole Fraction in Humid Gas Mixtures

Cited by 20 publications

References 23 publications

A $Q$ -Band Free-Space Characterization of Carbon Nanotube Composites

A $Q$ -Band Free-Space Characterization of Carbon Nanotube Composites

Industrial Implementation of the New Nir Laser-Based Sensor for Measuring Surface Moisture in Polymers

Measuring Humidity in Methane and Natural Gas with a Microwave Technique

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