Kelvin body

The numerical description of the growth of strain in the Kelvin body is ... 

The Kelvin body is a combination of the spring and dashpot in parallel. When elements are in parallel the stress of each element is added. 

The key point in the rheological classification of substances is the question as to whether the substance has a preferred shape or a natural state or not [19]. If the answer is yes, then this substance is said to be solid-shaped otherwise it is referred to as fluid-shaped [508]. The simplest model of a viscoelastic solid-shaped substance is the Kelvin body [396] or the Voigt body [508], which consists of a Hooke and a Newton body connected in parallel. This model describes deformations with time-lag and elastic aftereffects. A classical model of viscoplastic fluid-shaped substance is the Maxwell body [396], which consists of a Hooke and a Newton body connected in series and describes stress relaxation. 

Maxwell bodies are obtained if Hookean and Newtonian bodies are connected in series (Figure 11-11). The Kelvin or Voigt model, on the other hand, contains Hookean and Newtonian bodies in a parallel arrangement (Figure 11-11). The Maxwell body is a model for relaxation phenomena and the Kelvin body is a model for retardation processes. 

Macromolecular materials usually possess entropy elasticity together with viscous and energy-elastic components. Such behavior was only partly comprehensible by use of the models discussed up to now. It can be described very satisfactorily, however, by a four-parameter model in which a Hooke body, a Kelvin body, and a Newton body are combined (see the lowest figure in Figure 11-11). With this model, the deformation must again be added, i.e., with Equations (11-49), (11-52), and (11-57),... 

A Kelvin body combined in series with a spring. 

Earlier in the theory of viscoelasticity many rheological models with combinations of the Maxwell and the Voigt - Kelvin bodies were considered (see Freudental and Geiringer [1]). These models have constitutive laws for stresses o j and strains eij which include time derivatives of arbitrary order. 

Wc see that the system of Fig 13 exhibits features both of the Maxwell liquid (Fig. 14) and of the Kelvin body (Fig. 17). The permanent deformation als occurs in Fig 14, the elastic after-effect only in Fig. 17 ... 

The wavelength of ripples on the surface of a deep body of liquid depends on the surface tension. According to a formula given by Lord Kelvin [97],... 

In general, therefore, there are three processes, prior to the kind of capillary condensation associated with the hysteresis loop of a Type IV isotherm, which may occur in a porous body containing micropores along with mesoporesia primary process taking place in very narrow micropores a secondary, cooperative process, taking place in wider micropores, succeeded by a tertiary process governed by a modified Kelvin equation. 

CCT refers to the appearance of the light generated by a very hot (i.e., incandescent) object, the temperature of which is measured in kelvins (K). As a body is heated, it begins to produce a reddish-yellow, and then a yellow-white light. As temperature increases, the apparent color of the light changes to blue-white. In astronomy, for example, older, cooler... 

The maximum amount of work obtainable from a given quantity of heat, called its motivity by Lord Kelvin (1852), is thus always less than the mechanical equivalent of the quantity of heat, except in the limiting case when the refrigerator is at absolute zero (T2 = 0). It cannot be specified in terms of the condition of the body from which the heat is taken, or into which the heat passes, but requires in addition a knowdedge of the lowest available temperature, T2. For if we had another body at temperature T0, where T0 < T2, which could be used as a refrigerator, the amount of work ... 

The full significance of these observations could not be appreciated in advance of the formulation of the second law of thermodynamics by Lord Kelvin and Clausius in the early 1850 s. In a paper published in 1857 that was probably the first to treat the thermodynamics of elastic deformation, Kelvin showed that the quantity of heat Q absorbed during the (reversible) elastic deformation of any body is related in the following manner to the change with temperature in the work — TFei required to produce the deformation ... 

SAQ 8.24 A person is ill. The rate at which their antibodies react needs to increase twofold. This rate increase is achieved by raising the body s temperature from 37 °C to 40 °C. What is the activation energy of the reaction [Hint first convert from Celsius to kelvin.]... 

We have developed the idea that we can describe linear viscoelastic materials by a sum of Maxwell models. These models are the most appropriate for describing the response of a body to an applied strain. The same ideas apply to a sum of Kelvin models, which are more appropriately applied to stress controlled experiments. A combination of these models enables us to predict the results of different experiments. If we were able to predict the form of the model from the chemical constituents of the system we could predict all the viscoelastic responses in shear. We know that when a strain is applied to a viscoelastic material the molecules and particles that form the system gradual diffuse to relax the applied strain. For example, consider a solution of polymer... 

The rate of radiant thermal energy transfer between two bodies is described by the Stefan-Boltzmann law. Originally proposed in 1879 by Joseph Stefan and verified in 1884 by Ludwig Boltzmann, the Stefan-Boltzmann law states thatthe emission of thermal radiative energy is proportional to the fourth power of the absolute temperature (Kelvin or Rankine) ... 

A measure of the energy content or thermal content of a body or entity. A parameter that determines the directional transfer of heat to or from other bodies or entities. The SI temperature unit is the kelvin (abbreviated as K, and not °K). 

In which element or model for a viscoelastic body will the elastic response be retarded by viscous resistance (a) Maxwell or (b) Voigt-Kelvin ... 

PROBLEM 1.7 The normal body temperature of a healthy adult is 98.6°F. What is this value on both Celsius and Kelvin scales ... 

Finlayson and Hordley (2001 a,b) have developed a method for color constancy at a pixel. They make two assumptions. One that the camera s sensors are sufficiently narrow band and that the illuminant can be approximated by a black-body radiator. If the sensor s response functions are not sufficiently narrow band, a sharpening technique can be used (Barnard et al. 2001 Finlayson and Funt 1996 Finlayson et al. 1994a,b). The power spectrum of a black-body radiator was described in Section 3.5. The radiance of a black-body radiator at a temperature T, measured in Kelvin, at wavelength /. is given by (Haken and Wolf 1990 ... 

As an example, what is body temperature (98.6°F) on the Kelvin scale ... 

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