Wavelength-dependent excess permittivity as indicator of kerosene in diesel oil

Kanyathare, Boniphace; Peiponen, Kai–Erik

doi:10.1364/ao.57.002997

Cited by 12 publications

(17 citation statements)

References 16 publications

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“…The interaction of molecules in binary mixture, i.e. chemical activity of liquids, manifests in the optical properties of the binary mixture that is reflected in properties such as the refractive index and extinction coefficient of the binary mixture [17]. We have also shown the failure of the common Lorentz-Lorenz law, typically used for the description of optical properties of binary mixture, for adulterated diesel oils [18].…”

Section: Methodsmentioning

confidence: 84%

“…2. The presence of the kerosene in the diesel oil, therefore, influences the spreading of the liquids on the rough surface due to the interaction of the molecules of the different liquids [16][17][18]27]. However, the change in the internal interaction of the adulterated diesel is less evident in the refractive indices of the liquids as illustrated in Table 1.…”

Section: Resultsmentioning

confidence: 99%

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Table model and portable optical sensors for the monitoring of time-dependent liquid spreading over rough surfaces

Asamoah

Kanyathare

Peiponen

2018

J. Eur. Opt. Soc.-Rapid Publ.

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Background: Many applications require liquids to efficiently wet required surfaces as it denotes better performance. The dynamics of pure and complex liquid is known to influence the spreading properties; however, this influence is less understood and solicits other measuring techniques to elucidate the grey area. In this work, we demonstrate the use of simple yet novel optical methods in the monitoring of liquid spreading of pure diesel and kerosene and their binary (complex) mixtures. Methods: The optical devices are a table model and portable optical sensors which use a diffractive optical element for filtering the specular reflection from a laser speckle pattern obtained from the liquid spreading on the rough surface-liquid-air system. The surfaces used in this study were metal surface roughness standards and roughened glass surface. The viability of the devices was demonstrated using two liquids, namely diesel oil and kerosene, that have a wide difference in their contact angles. The performance of the devices was further tested using binary mixtures of the diesel oil and kerosene. Based on the scattering properties of the spreading liquids and the surfaces, the time-dependent signal was measured with the optical devices. Results: It was observed that the spreading was influenced by the surface roughness. The magnitude of the signal decreased with increased surface roughness indicating less variation in the spreading of the liquid drop with the increased surface roughness. The nature of the detected signal for the kerosene on the surface with roughness values below the wavelength of the device follows the Tanner's law of drop spreading. However, the diesel spreads at a lower rate. Additionally, the complexity of the internal interaction of the diesel-kerosene binary mixtures leads to a complex spreading mechanism on the solid surfaces allowing us to screen the adulterated liquids from the authentic diesel oil with high reliability. Conclusion: We have introduced two novel optical sensors (table model and portable) for the detection of the changes in liquid drop spreading over rough surfaces. The spreading of the liquid drops over a rough surface causes a local contact angle that experiences hysteresis during the spreading process. The spreading depends on the complexity of the liquid and the magnitude of the surface roughness. The unique configuration of the devices makes the portable sensor suitable for longer duration measurements and for field applications, whilst the table model is best suited for monitoring the first transient moments of liquid spreading and for laboratory applications. Such spreading techniques can also be utilized in the detection of wine and strong alcohol, such as vodka, adulterations with glycol and water, respectively.

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Section: Methodsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 99%

Table model and portable optical sensors for the monitoring of time-dependent liquid spreading over rough surfaces

Asamoah

Kanyathare

Peiponen

2018

J. Eur. Opt. Soc.-Rapid Publ.

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“…The imaginary excess permittivity can be derived from the equation for the excess permittivity of binary mixtures. If we denote the complex relative permittivity of diesel oil by ε D and the corresponding permittivity of kerosene by ε K , we can express the complex excess relative permittivity (here after we use the expression for permittivity, meaning that it is the dimensionless relative permittivity) as [9] (1)…”

Section: Theorymentioning

confidence: 99%

“…In our recent studies of adulterated diesel oils, we have learned that when using either an Abbe refractometer or a spectrophotometer, there are cases when one may need additional complementary methods to reliably confirm diesel oil adulteration. To circumvent this issue, we have proposed a combination of both refractive index and NIR transmittance measurements, along with exploitation of the so-called excess permittivity of a binary mixture to obtain a more comprehensive picture of adulterated diesel oils [9]. In other words, we have shown that the real part of the complex excess permittivity of adulterated diesel oil reveals fine structures of spectral fingerprints that can be used to screen adulterated diesel oil.…”

Section: Introductionmentioning

confidence: 99%

“…In other words, we have shown that the real part of the complex excess permittivity of adulterated diesel oil reveals fine structures of spectral fingerprints that can be used to screen adulterated diesel oil. The study reported in this paper is a continuation of [9], namely, we have investigated the imaginary part of the complex excess permittivity of authentic and adulterated diesel oils. It is shown that the combination of the real part of the refractive index, the imaginary part of the refractive index (obtained from the absorption coefficient of the fuel), and the imaginary part of the excess permittivity of adulterated diesel oils, provides a plausible means of deciding with confidence the relative amounts of kerosene adulteration in diesel oils.…”

Section: Introductionmentioning

confidence: 99%

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Imaginary optical constants in near-infrared (NIR) spectral range for the separation and discrimination of adulterated diesel oil binary mixtures

Kanyathare

Asamoah

Peiponen

2018

Opt Rev

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Fuel adulteration is a major factor contributing to environmental pollution. The tendency to adulterate diesel oil with kerosene is becoming prevalent in many countries, which is particularly driven by the lower cost of kerosene than of diesel oil. The objective of this study is to develop a method of separating and discriminating between different compositions of kerosene in binary liquid fuel mixtures. In this study, we have utilized refractive indices of binary fuel mixtures measured using an Abbe refractometer, and the inversion of measured transmittance spectra in the visible and near-infrared (NIR) spectral range by a general method based on Kramers-Kronig dispersion analysis, where the singly subtractive Kramers-Kronig relations have been used to obtain the wavelength-dependent imaginary excess permittivity of a binary liquid mixture. The excess permittivity has considerable importance in the interpretation of different liquid molecule interactions in binary liquid mixtures. It is herein demonstrated that the problematic cases of relatively low adulterations of 5% and 10% can be detected and distinguished from 15% adulteration using imaginary optical properties in the NIR spectral range. We show that imaginary optical constants such as excess imaginary permittivity and the extinction coefficient are useful for not only screening for adulteration, but also discriminating and separating low from high kerosene compositions in mixtures. Moreover, these quantities can also be exploited for the development of practical sensors, especially for sensing diesel oil adulteration under field conditions.

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