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The linear viscoelastic relaxation of liquids and mixtures in the frequency range 5-450 MHz
Başlık:
The linear viscoelastic relaxation of liquids and mixtures in the frequency range 5-450 MHz
Yazar:
Erginsav, Aynur, author.
ISBN:
9780438052468
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (284 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Advisors: A. J. Barlow.
Özet:
The linear viscoelastic behaviour of a wide range of pure supercooled liquids and mixtures has been studied in the frequency range 5 - 450 MHz. In all cases, the dependence of steady-flow viscosity upon temperature follows the equation lneta = A + B/(T-T0 )which is derived from the free volume equation with a linear dependence of density upon temperature. For all liquids investigated, the limiting shear rigidity modulus, Goo varies with temperature according to the relationship [mathematical equation]. Measurements have been made of the viscoelastic properties of binary mixtures of pure liquids which separately conform to the prediction of the empirical equation. In all cases, it is found that viscoelastic relaxation in these systems can be accounted for by the introduction of a single additional constant, K, into the equation for the complex compliance such that For binary mixtures in which the two components have either closely similar molecular weights or are isomers, the value K = 1 applies for all concentrations investigated. However if the components of the mixture differ appreciably in molecular weight, a systematic variation of K with mole fraction is found. K varies between 0.25 to 1.80 and a single curve of K against mole fraction of the lower molecular weight components represents the results obtained on four such mixtures of liquids which differ significantly in molecular composition. Greater values of K are found for more complex mixtures, e.g. for castor oil K = 2.90. Detailed analysis of results showed that the empirical equation is valid only over a limited frequency and hence viscosity range. It was found that the results for the viscoelastic relaxation in liquids and mixtures can be interpreted in terms of Glarum's defect-diffusion model which corresponds to a non-exponential correlation function for molecular reorientation. The linear viscoelastic behaviour of a wide range of pure supercooled liquids and mixtures has been studied in the frequency range 5 - 450 MHz.
Notlar:
School code: 0547
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(684392.1) | 684392-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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