Mechanical damping parameter

The loss tangent (tan 8) is a dimensionless term that describes the ratio of the loss modulus (G") to the storage modulus (G ), and this may be usefully employed to convey information concerning the structure of the polymeric system in question. This is frequently referred to as the mechanical damping parameter. To substantiate... 

Internal friction (IF), e.g. [102]. IF is a mechanical testing procedure which may be understood as a special technique of DMT A. The mechanical damping of the free oscillation is measured depending on the temperature at a constant frequency. The internal friction parameter is proportional to the natural logarithm of the ratio of two subsequent amplitudes of the oscillation and hence is also related to the damping factor tan (5, (see also section 12.1). 

Mechanical systems are usually considered to comprise of the linear lumped parameter elements of stiffness, damping and mass. 

Further extensions of the model are required to address the dynamical consequences of these additional regulatory loops and of the indirect nature of the negative feedback on gene expression. Such extended models have been proposed for Drosophila [112, 113] and mammals [113]. The model for the circadian clock mechanism in mammals is schematized in Fig. 3C. The presence of additional mRNA and protein species, as well as of multiple complexes formed between the various clock proteins, complicates the model, which is now governed by a system of 16 or 19 kinetic equations. Sustained or damped oscillations can occur in this model for parameter values corresponding to continuous darkness. As observed in the experiments on the mammalian clock. Email mRNA oscillates in opposite phase with respect to Per and Cry mRNAs [97]. The model displays the property of entrainment by the ED cycle... 

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