Elastic force storage

Presence of a Number of Flexible Loops for Potential Storage of Elastic Force... 

Evaluation of elastic energy in systems with surface energy needs special care, for besides external forces, there are forces due to molecular attraction that cause elastic deformation and lead to elastic energy storage. 

The mechanical properties of actin filament networks depend on the manner in which actin monomer is prepared and stored, as well as how they are polymerized conditions. Differences in mechanical properties are not the consequence of using two different types of forced oscillatory rheometers. Xu et aid found that filaments assembled in EGTA and Mg from fresh, gel-filtered ATP-actin monomer (1 mg/mL) have an elastic storage... 

Fibrin is a viscoelastic polymer, which means that it has both elastic and viscous properties (Ferry, 1988). Thus, the properties of fibrin may be characterized by stiffness or storage modulus (representing its elastic properties) and creep compliance or loss modulus/loss tangent (representing its inelastic properties). These parameters will determine how the clot responds to the forces applied to it in flowing blood. For example, a stiff clot will not deform as much as a less stiff one with applied stress. 

External forces applied to tissues lead to stretching of collagen, elastic fibers, and smooth muscle in the associated ECMs as well as proteoglycan deformation and fluid flow from within the matrix. The application of these forces ultimately leads to matrix remodeling and energy storage. The question arises as to how external mechanical events trigger cellular synthesis. 

Mechanical loads can be applied in a static or a dynamic way. For static loads, the modulus of elasticity is a real quantity like the spring constant in Hooke s law. It is called the storage modulus, because it stores the applied work as potential energy of deformation. For dynamic loads a phase shift between the driving force and the sample deformation is observed. This phase shift is related to the loss modulus, which describes the energy uptake and the associated sample heating [Elil]. Therefore, for dynamic deformations the distribution of strains, the phase shifts between stress and strain, and the resulting distribution of temperatures are quantities of interest for materials characterization. 

The viscosities of polymer melts, calculated from the storage modulus and the loss modulus, have to be within a range to resist the applied forces, which act against the rheological forces. But they should not be as large as to prevent the necessary deformation before the start of sodification. The elastic part of deformation has to be small since an elastic deformation happens more rapidly than a viscous one. Therefore, a considerable elastic deformation can lead to a cohesive fracture of the fiber in the molten state. The ratio of the viscous to the elastic energy of the polymer melt may be seen as one of the most important factors for the spinnability of polymers. For the usual commercially used spinnable polymers, such as, for example, poly(ethylene terephthalate), the ratio is about G"/G >10... 

Flocculated Systems. The viscoelastic responses of flocculated systems are strongly dependent on the suspension structure. The suspension starts to show an elastic response at a critical solid volume fraction of 0ct = 0.05 — 0.07, at which the particles form a continuous three-dimensional network (211-213). The magnitude of the elastic response for flocculated suspensions above 0ct depends on several parameters, such as the suspension structure, interparticle attraction forces and particle size, and shape and volume fraction. Buscall et al. (10) found that the volume fraction dependence of the storage modulus follows a power-law behavior. 

The effect of the fillers on the dynamic mechanical property of NR material was analysed by DMA in this work. The elastic modulus ( ") and the loss factor (tan 5) of the neat NR and NR composites were characterized as functions of temperature. Under an oscillating force, the resultant strain in specimen depends upon both elastic and viscous behaviour of materials. The storage modulus reflects the elastic modulus of the rubber materials which measures t recoverable strain energy in a deformed specimen, and the loss factor is related to the energy damped due to energy dissipation as heat. 

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