Spring force constant

The resistance to plastic flow can be schematically illustrated by dashpots with characteristic viscosities. The resistance to deformations within the elastic regions can be characterized by elastic springs and spring force constants. In real fibers, in contrast to ideal fibers, the mechanical behavior is best characterized by simultaneous elastic and plastic deformations. Materials that undergo simultaneous elastic and plastic effects are said to be viscoelastic. Several models describing viscoelasticity in terms of springs and dashpots in various series and parallel combinations have been proposed. The concepts of elasticity, plasticity, and viscoelasticity have been the subjects of several excellent reviews (21,22). 

The determination of the rate constant ki requires estimation of the concentration of Q in the average enzyme plane. It may be estimated using the following expression of the concentration profile derived from a model in which the PEG chain is approximated by a spring (force constant yspi ) ... 

Xspr spring force constant of the polyethyleneglycol chains... 

It is proportional to the strength of the spring (force constant k of the bond in dynes per centimetre) and reciprocally proportional to both masses in grams (v is the wavenumber of frequency 1/A in cm", c is the velocity of light andp is the reduced mass). 

Dependence of parameters of proton transfer potentials (A and kcal/mol) upon the length of spring. Force constant k is equal to 8 mdyn/A. 

Substitution of W(A/ ,y) into the expression AA = —ksT lnlV(A/ ,y) for the elastic free energy change associated with the fluctuation AR,y leads to the harmonic potential k Ty ARfj, or the Hooke spring force constant of Ik Ty for the interaction between all residue pairs separated by / ,y < Kq. The single parameter y reflects the stiffness of nonbonded interactions in a given protein. We note that previous detailed... 

A molecular vibration involves motion of all of the atoms in the system. As such, there is usually no easy way to describe the motion. One convenient descriptor is to consider the equivalent vibration of a mass on a spring attached to an immovable point. The frequency of such a vibration is related to the mass and the spring force-constant as in equation (9). 

Consider a spring with a force constant k such that one end of the spring is attached to an immovable object such as a wall and the other is attached to a mass, m (see Figure 1-1). Hamiltonian mechanics will be used hence, the first step is to determine the Hamiltonian for the problem. The mass is confined to the x-axis and will have both kinetic and potential energy. The potential energy is the square of the distance the spring is displaced from its equilibrium position, xo, times one-half of the spring force constant, k (Hooke s Law). 

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