WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

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Publisher: search.filters.publisher.Taylor and Francis Ltd.Subject: search.filters.subject.Diffusion

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  • Article
    Citation - WoS: 21
    Citation - Scopus: 23
    Determination of Octane Number of Gasoline Using Near Infrared Spectroscopy and Genetic Multivariate Calibration Methods
    (Taylor and Francis Ltd., 2005) Özdemir, Durmuş
    The feasibility of rating the octane number of gasoline using near infrared (NIR) spectroscopy and three different genetic algorithm-based multivariate calibration methods was demonstrated. The three genetic multivariate calibration methods are genetic regression (GR), genetic classical least squares (GCLS), and genetic inverse least squares (GILS). The sample data set was obtained from the ftp address (ftp://ftp.clarkson.edu/pub/hopkepk/Chemdata/) with the permission of Professor. J. H. Kalivas. This data set contains the NIR spectra of 60 gasoline samples collected using diffuse reflectance as log (I / R) with known octane numbers and covers the range from 900 to 1700 nm in 2 nm intervals. Of these 60 spectra, 20 were used as the calibration set, 20 were used as the prediction set, and 20 were reserved for the validation purposes. Several calibration models were built with the three genetic algorithm-based methods, and the results were compared with the partial least squares (PLS) prediction errors reported in the literature. Overall, the standard error of calibration (SEC), standard error of prediction (SEP), and standard error of validation (SEV) values were in the range of 0.15-0.32 (in the units of motor octane number) for the GR and GILS, which are comparable with the literature. However, GCLS produced relatively large results (0.36 for SEC, 0.39 for SEP and 0.52 for SEV) when compared with the other two methods.
  • Article
    Citation - WoS: 4
    Citation - Scopus: 4
    A Chromatographic Study of Carbon Monoxide Adsorption on a Clinoptilolite-Containing Natural Zeolitic Material
    (Taylor and Francis Ltd., 2004) Narin, Güler; Yılmaz, Selahattin; Ülkü, Semra
    In this study, the equilibrium and kinetic parameters for CO adsorption on clinoptilolite-rich natural zeolitic material were determined by the concentration pulse chromatography technique. Experiments were carried out at different column temperatures (60-120°C) and interstitial carrier gas velocities (3.1-16.3 cm/s) using a clinoptilolite-rich natural zeolitic material packed column. The equilibrium and kinetic parameters were determined by matching the moments of the experimentally obtained response curves to the parameters in the mathematical model. The Henry's Law constants were found to decrease from 700 to 49 with increasing temperature. The heat of adsorption at low coverage was found to be 50.73 kJ/molK. The contributions from external film, macropore, and micropore diffusion resistances to mass transfer were determined, and the micropore diffusion resistance was found to be the major contributor. The micropore diffusivity as a function of crystal radius (Dc/rc 2) was determined and found to change between 5.72 × 10-4 and 1.34 × 10-2 s-1 in the temperature range studied.