Determination of the water content in petroleum products using terahertz transmission spectroscopy

Gorenflo, Stefan; Tauer, Ulrike; Hinkov, I.; Lambrecht, A.; Helm, H.

doi:10.1117/12.644495

Cited by 12 publications

(6 citation statements)

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“…While at higher frequencies the data become noisier due to the dynamic range of the system which is limited at approximately 2.0THz [18] . Accordingly, in the analysis procedure, the absorption spectra between 0.2 and 2.0 THz are selected as the feature to classify them.…”

Section: Resultsmentioning

confidence: 98%

Classification of tea based on terahertz time domain spectroscopy

Cao

Zhang

Ze-kui

2008

Photonics and Optoelectronics Meetings (POEM) 2008: Terahertz Science and Technology

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Terahertz time-domain spectroscopy (THz-TDS) is a newly developed technique in the last decade. A new method to classify tea is proposed based on THz-TDS and pattern recognition method. Four kinds of tea are investigated to study its feasibility. Their absorption spectra are measured using the THz-TDS system. Then a pattern recognition method, support vector machine (SVM), is employed to differentiate the investigated tea based on their terahertz data. The absorption spectra between 0.2 and 2.0 THz of the investigated tea samples are selected as the feature to classify them.The correct rate of recognition for the SVM classifier is 96.88%. The results give evidence that different tea varieties can be distinguished based on their terahertz spectra. In this respect, the spectral method provides enough information to differentiate different kinds of tea.

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Section: Resultsmentioning

confidence: 98%

Classification of tea based on terahertz time domain spectroscopy

Cao

Zhang

Ze-kui

2008

Photonics and Optoelectronics Meetings (POEM) 2008: Terahertz Science and Technology

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“…This behavior is considered as inclusions with the dielectric function ei (water droplets) in a host medium ch (oil) forming an effective medium with the dielectric constant 8eff. For a further evaluation we use the Maxwell-Garnett effective medium approximation (MG-EMA) 8eff h ei-C eff +t2hh 8i±2hh (1) where f denotes the volume fraction of inclusions. The experiments demonstrate that for water concentrations f>1% the model is in good agreement with the experimental data.…”

Section: Methodsmentioning

confidence: 99%

“…The measurements have been performed with the THz-TDS setup described in [1]. For polar oils the water is dissolved via hydrogen bonds [2].…”

Section: Methodsmentioning

confidence: 99%

Analysis Methods of Oil Contamination for Terahertz Frequencies

Gorenflo

Tauer

Hinkov

et al. 2006

2006 Joint 31st International Conference on Infrared Millimeter Waves and 14th International Conference on Teraherz Electronics

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Terahertz Time-Domain Spectroscopy (THz-TDS) is used to investigate water and soot contaminations in oils, exhibiting different dilution modes. For synthetic polyglycol oils, the water is dissolved due to the polar behavior of the oil, whereas in non polar mineral oils the water-oil compound forms an emulsion. This behavior is modeled with an effective medium approximation (EMA) formalism. Small soot agglomerates are remaining in suspension when mineral oils are polluted with soot particles. In this case, the absorption spectrum is dominated by scattering effects. Due to the small particle size of the soot agglomerates compared to the THz wavelength, coherent scattering is the dominant process.

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“…The analyzed data of Figure From this result we can estimate that on the basis of the fit, a water concentration within the examined region determined by THz-TDS differs less than 0.1 % from the value derived by the Karl Fischer method. The sensitivity we achieve with the THz-Experiment is in the same range like it is applying Fourier Transform Infrared (FTIR) spectroscopy to determine the water concentration in petroleum products, 16 where the area below an OH-band (e.g. 3598-3732 cm -1 ) is used to determine water contamination.…”

Section: Dissolved Water-in-oil Compoundmentioning

confidence: 99%